CN106297814A - Speech signal processing apparatus and speech signal processing method - Google Patents

Abstract

The invention provides a voice signal processing device and a voice signal processing method. The first sampling point in the mth original frequency-down signal frame, which is phase-matched with the sampling point corresponding to the phase reference sampling point number, is determined according to the phase reference sampling point number corresponding to the middle sampling point of the (m-1) th updated frequency-down signal frame in the (m-1) th original frequency-down signal frame. The continuous q sampling points from the first sampling point are used as the sampling points of the mth updated down-converted signal frame, so that when the sampled voice signal is further down-converted (for example, the frequency is reduced to one fourth), the signal distortion caused by phase mismatch when the signal frames are overlapped can be effectively improved.

Description

Speech signal processing device and speech signal processing method

technical field

The present invention relates to a signal processing device, and in particular to a voice signal processing device and a voice signal processing method.

Background technique

Generally, hearing-impaired people often cannot clearly receive higher-frequency speech signals, such as consonant signals, but can clearly hear low-frequency signals. Generally, the prior art solves this problem by reducing the frequency of the high-frequency voice signal and overlapping the signal frames. After the signal is down-frequency, since the time length becomes longer, the signal value between two consecutive sampling signals needs to be obtained by means of interpolation. Since the characteristics of the sound signal are relatively close to the sine wave, if the interpolated signal value is obtained by the general arithmetic mean method, the signal after frequency reduction will often be distorted. In addition, the existing technology does not consider whether the phases of the signal frames are matched when performing the overlapping action of the signal frame. Therefore, a part of the signal will be added and a part of the signal will be subtracted at the overlap, which will cause signal distortion. The greater the frequency reduction, the more serious the distortion will be.

Contents of the invention

The present invention provides a speech signal processing device and a speech signal processing method, which can effectively improve signal distortion caused by phase mismatch when signal frames overlap when further down-converting the sampled speech signal.

The speech signal processing device of the present invention includes a processing unit, which is used to down-sample the speech signal to generate a down-frequency signal including a sequence of original down-frequency signal frames, and generate corresponding updated down-frequency signal frames according to the original down-frequency signal frames , wherein each original down-frequency signal frame includes p sampling points. The processing unit also determines the m-th original down-frequency signal frame according to the phase reference sampling point number corresponding to the middle sampling point of the m-1th update down-frequency signal frame in the m-1th original down-frequency signal frame The first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number, and the continuous q sampling points from the first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number are taken as the mth Update the sampling point of the down-frequency signal frame, and alias the adjacent updated down-frequency signal frame to generate an overlapping voice signal, wherein the phase reference sampling point number is in the m-1th original down-frequency signal frame and the mth -1 serial number of the sampling point corresponding to the middle sampling point of the update down-frequency signal frame, p and q are positive integers, and m is a positive integer greater than 1.

In an embodiment of the present invention, the frequency of the above-mentioned down-frequency signal is 1/4 of the sampled speech signal, and the length of each updated down-frequency signal frame is equal to 1/2 of the length of each original down-frequency signal frame.

In an embodiment of the present invention, the two adjacent updated down-frequency signal frames respectively have 50% overlapping sections.

In an embodiment of the present invention, the above-mentioned processing unit also accumulates the first count value and the second count value according to the sampling value of the sampling point in the m-th original down-frequency signal frame, wherein when counting to a sample whose corresponding sampling value is 0 point or at least one sampling point adjacent to the sampling point whose sampling value is 0, reset the first count value or the second count value to zero. The processing unit takes the first count value or the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame as a reference value, and determines the m-th original down-frequency signal according to the reference value The first sample point in the frame that matches the phase of the sample point corresponding to the phase reference sample point number.

In an embodiment of the present invention, the processing unit further judges whether the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the m-1th The second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the original down-frequency signal frame. If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is less than or equal to the value corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame For the second count value corresponding to the sampling point, the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is used as a reference value, and the m-th original down-frequency When the first count value in the down-frequency signal frame is equal to the reference value, the earliest sampled sample point is used as the first sample of the phase matching of the sample point corresponding to the phase reference sample point number in the m-th original down-frequency signal frame point, if the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is not less than or equal to the phase reference sampling point in the m-1th original down-frequency signal frame For the second count value corresponding to the sampling point corresponding to the serial number, the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is used as a reference value, and the m-th The earliest sampled sampling point among the corresponding sampling points when the second count value in the first down-frequency signal frame is equal to the reference value is used as the phase-matched sampling point corresponding to the phase reference sampling point number in the m-th original down-frequency signal frame. a sampling point.

In an embodiment of the present invention, the processing unit further multiplies the down-frequency signal by a Hamming window.

In an embodiment of the present invention, the above-mentioned processing unit calculates the value of the interpolation parameter function corresponding to each original down-frequency signal frame according to three consecutive sampling values in each original down-frequency signal frame, and calculates the value of the interpolation parameter function corresponding to each original down-frequency signal frame, and The value of the interpolation parameter function corresponding to the signal frame calculates the interpolation value between two adjacent sampling points in each original down-frequency signal frame.

In an embodiment of the present invention, the processing unit further judges whether the value of the interpolation parameter function is less than the upper limit and greater than or equal to the lower limit, if the value of the interpolation parameter function is not less than the upper limit or not greater than or equal to the lower limit Value, modify the value of the interpolation parameter function, if the value of the interpolation parameter function is greater than or equal to the upper limit value, the value of the interpolation parameter function will be corrected to the upper limit value, if the value of the interpolation parameter function is less than the lower limit value, it will be The value of the interpolation parameter function is corrected to the lower limit value.

In an embodiment of the present invention, the above-mentioned sampled speech signal is generated by sampling the original speech signal, and the upper limit and the lower limit are associated with the frequency of the original speech signal and the sampling frequency of sampling the original speech signal.

In an embodiment of the present invention, the above-mentioned processing unit also calculates the interpolation parameter function corresponding to each original down-frequency signal frame according to the trigonometric function relationship between three consecutive sampling values in each original down-frequency signal frame, wherein the interpolation parameter The function is a trigonometric function.

The speech signal processing method of the present invention includes the following steps. The speech signal is down-sampled to generate a down-frequency signal including a sequence of original down-frequency signal frames, wherein each original down-frequency signal frame includes p sampling points, where p is a positive integer. According to the phase reference sampling point number corresponding to the middle sampling point in the m-1th original down-frequency signal frame and the m-1th updated down-frequency signal frame The first sampling point of the phase matching of the sampling point corresponding to the sampling point number, where m is a positive integer greater than 1, and the phase reference sampling point number is in the m-1th original down-frequency signal frame and the m-1th update The number of the sampling point corresponding to the middle sampling point of the down-frequency signal frame. The continuous q sampling points starting from the first sampling point phase-matched with the sampling point number corresponding to the phase reference sampling point number are taken as the sampling points of the mth update down-frequency signal frame, where q is a positive integer. Adjacent frames of the updated down-converted signal are aliased to produce an overlapping speech signal.

In an embodiment of the present invention, the frequency of the above-mentioned down-frequency signal is 1/4 of the sampled speech signal, and the length of each updated down-frequency signal frame is equal to 1/2 of the length of each original down-frequency signal frame.

In an embodiment of the present invention, the two adjacent updated down-frequency signal frames respectively have 50% overlapping sections.

In an embodiment of the present invention, the m-th is determined based on the phase reference sampling point number corresponding to the middle sampling point of the (m-1)th updated down-frequency signal frame in the (m-1)th original down-frequency signal frame. The step of the first sampling point phase-matched with the sampling point corresponding to the phase reference sampling point number in the first down-frequency signal frame comprises the following steps: accumulating the first count according to the sampling value of the sampling point in the m-th original down-frequency signal frame value and a second count value, wherein when counting to a sampling point corresponding to a sampling value of 0 or at least one sampling point adjacent to a sampling point with a sampling value of 0, the corresponding first counting value or second counting value is reset to zero value. The first count value or the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame is used as the reference value. The first sampling point of the phase matching of the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame is determined according to the reference value.

In an embodiment of the present invention, the above-mentioned step of using the first count value or the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame as a reference value includes the following steps : Determine whether the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the phase reference sampling point number in the m-1th original down-frequency signal frame The second count value corresponding to the corresponding sampling point. If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is less than or equal to the value corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame For the second count value corresponding to the sampling point, the first count value corresponding to the sampling point corresponding to the number of the phase reference sampling point in the m-1th original down-frequency signal frame is used as a reference value. If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is not less than or equal to the phase reference sampling point number corresponding to the m-1th original down-frequency signal frame The second count value corresponding to the sampling point of , the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is used as the reference value.

In an embodiment of the present invention, if the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the m-1th original down-frequency signal frame In the second count value corresponding to the sampling point corresponding to the phase reference sampling point number, the above-mentioned speech signal processing method includes: in the sampling point corresponding to the first count value in the mth original down-frequency signal frame when it is equal to the reference value The earliest sampled sampling point is used as the first sampling point for phase matching of the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame.

In an embodiment of the present invention, if the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame is not less than or equal to the phase number in the m-th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the reference sampling point number, the above-mentioned speech signal processing method includes: the earliest sampled value in the sampling point corresponding to the second count value in the mth original down-frequency signal frame when it is equal to the reference value The sampling point is used as the first sampling point phase-matched with the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame.

In an embodiment of the present invention, the speech signal processing method includes multiplying the down-frequency signal by a Hamming window.

In one embodiment of the present invention, the above-mentioned voice signal processing method includes the following steps: calculating the value of the interpolation parameter function corresponding to each original frequency-reduction signal frame according to three consecutive sampling values in each original frequency-reduction signal frame; judging Whether the value of the interpolation parameter function is less than the upper limit value and greater than or equal to the lower limit value, if the value of the interpolation parameter function is not less than the upper limit value or not greater than or equal to the lower limit value, the value of the interpolation parameter function is corrected; The value of the interpolation parameter function corresponding to the signal frame calculates the interpolation value between two adjacent sampling points in each down-frequency signal frame.

In one embodiment of the present invention, if the value of the interpolation parameter function is greater than or equal to the upper limit value, the value of the interpolation parameter function is corrected to the upper limit value, and if the value of the interpolation parameter function is smaller than the lower limit value, the value of the interpolation parameter function is changed to The value of the interpolation parameter function is modified to a lower limit value, wherein the sampled speech signal is generated by sampling the original speech signal, and the upper limit value and the lower limit value are related to the frequency of the original speech signal and the sampling frequency of the original speech signal.

In an embodiment of the present invention, the above speech signal processing method includes calculating the interpolation parameter function corresponding to each original down-frequency signal frame according to the trigonometric function relationship between three consecutive sampling values in each original down-frequency signal frame, wherein The interpolation parameter functions are trigonometric functions.

Based on the above, the embodiments of the present invention determine the m-th original The first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number in the down-frequency signal frame, and the continuous q samples from the first sampling point phase matching of the sampling point corresponding to the phase reference sampling point number The point is used as the sampling point of the mth update down-frequency signal frame, so that when the sampled speech signal is further down-frequency (for example, the frequency is reduced to a quarter), it can still effectively improve the phase mismatch when the signal frame overlaps resulting signal distortion.

Description of drawings

FIG. 1 is a schematic structural diagram of a speech signal processing device according to an embodiment of the present invention;

FIG. 2 shows a schematic diagram of signal processing of a sampled speech signal according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a down-frequency signal according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of an original down-frequency signal frame WL3 according to an embodiment of the present invention;

FIG. 5 is a schematic flow diagram of a voice signal processing method according to an embodiment of the present invention;

FIG. 6 is a schematic flow diagram of a voice signal processing method according to another embodiment of the present invention;

Fig. 7 is a schematic flowchart of a speech signal processing method according to another embodiment of the present invention.

Explanation of reference signs:

102: processing unit;

104: sampling unit;

S1: original voice signal;

S2: Sampling the voice signal;

W1～W4: Sampling signal frame;

WL1～WL4: Original down-frequency signal frame;

WL1'～WL4': update the down-frequency signal frame;

WH1～WH4: update down-frequency signal frame after multiplying by Hamming window;

SL, SL', SH: down-frequency signal;

s _m (4n), s _m (4n+4), s _m (4n+8): sampling points;

s _m (4n+1), s _m (4n+2), s _m (4n+3), s _m (4n+5), s _m (4n+6), s _m (4n+7): interpolation point;

SO: overlapping speech signal;

first count value;

n: sampling point number;

Wm: the mth original down-frequency signal frame;

S502-S510, S602-S608, S702-S712: Steps in the voice signal processing method.

detailed description

FIG. 1 is a schematic structural diagram of a speech signal processing device according to an embodiment of the present invention, please refer to FIG. 1 . The speech signal processing device includes a processing unit 102 and a sampling unit 104, the processing unit 102 is coupled to the sampling unit 104, wherein the processing unit 102 can be implemented as a central processing unit, and the sampling unit 104 can be implemented as a logic circuit, otherwise This is the limit. The sampling unit 104 can sample the original speech signal S1 to generate a sampled speech signal S2. The processing unit 102 can down-sample the voice signal S2 to generate a down-frequency signal comprising a sequence of down-frequency signal frames. FIG. 2 shows a schematic diagram of signal processing of a sampled voice signal according to an embodiment of the present invention. As shown in FIG. 2 , The sampled speech signal S2 may include a sequence of sampled signal frames. For simplicity of description, only 4 sampled signal frames W1 - W4 are shown in the embodiment of FIG. 2 , but it is not limited thereto. The down-frequency signal SL includes a plurality of original down-frequency signal frames WL1-WL4. Since the down-frequency signal SL is obtained by down-sampling the voice signal S2, the length of the original down-frequency signal frame is greater than the length of the sampling signal frame of the sampled voice signal S2. , in the present embodiment, the frequency of the down-frequency signal SL is 1/4 of the sampled speech signal S2 (therefore the length of each original down-frequency signal frame is 4 times the length of its corresponding sampled signal frame), but not limit.

The processing unit 102 can select some sampling points from the original down-frequency signal frame to obtain an updated down-frequency signal frame (for example, the updated down-frequency signal frames WL1'˜WL4' in FIG. 2, in this embodiment, each updated down-frequency signal frame The length of the signal frame is equal to 1/2 of the length of each original down-frequency signal frame), and the phase matching between the intermediate sampling point of each update down-frequency signal frame and the initial sampling point of the next update down-frequency signal frame, thereby improving Signal distortion caused by phase mismatch when signal frames overlap.

In detail, part of the sampling points in the frame of the original down-converted signal can be obtained, for example, by performing an interpolation operation. The processing unit 102 can first calculate the value of the interpolation parameter function corresponding to each original down-frequency signal frame based on the known three consecutive sampling values in each original down-frequency signal frame, and then calculate the value of the interpolation parameter function corresponding to each original down-frequency signal frame. The value of the interpolation parameter function is used to calculate the interpolation value between two adjacent known sampling points in each original down-frequency signal frame, wherein the interpolation parameter function is a trigonometric function, such as a sine function or a cosine function, but not limited thereto.

For example, FIG. 3 shows a schematic diagram of a down-frequency signal according to an embodiment of the present invention, please refer to FIG. 3 . In FIG. 3 , the solid circles are the known sampling points in the original down-frequency signal frame, and the hollow circles are the interpolation points calculated by the processing unit 102 based on the known sampling points. The part of the square point is the interpolation point calculated by the processing unit 102 by performing an interpolation operation based on the known sampling point and the calculated interpolation point. The processing unit 102 can calculate the interpolation parameter function corresponding to each original down-frequency signal frame according to the sampling values of three consecutive known sampling points in each original down-frequency signal frame, for example, the mth original down-frequency signal frame Wm The corresponding interpolation parameter function C _m (g) can be based on the three sampling points s _m (4n), s _m (4n+4) and s _m (4n+8) continuously sampled in the original down-frequency signal frame In the time range of the original down-frequency signal frame Wm, its corresponding interpolation parameter function can be shown in the following formula:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 4</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Where g is 0 or a positive integer, C _m (g) is the function value of the interpolation parameter function at time point g, and the interpolation parameter function C _m (g) is a trigonometric function.

Since the speech signal processing device may generate noise during the signal processing, the calculated value of the interpolation parameter function contains noise components, which will affect the accuracy of the interpolation value obtained by the processing unit 102 . The processing unit 102 can monitor whether the value of the interpolation parameter function is disturbed by noise by judging whether the value of the interpolation parameter function falls within a preset range, for example, it can judge whether the value of the interpolation parameter function is less than the upper limit and greater than or equal to Lower limit value, if the value of the interpolation parameter function is not less than the upper limit value or not greater than or equal to the lower limit value, it means that the value of the parameter function is disturbed by noise, and the processing unit 102 can correct the value of the interpolation parameter function to remove the interpolation The noise component included in the value of the parametric function. For example, if the value of the interpolation parameter function is greater than or equal to the upper limit value, the processing unit 102 can modify the value of the interpolation parameter function to the upper limit value; The value of the interpolation parameter function is corrected to the lower limit value, and if the value of the interpolation parameter function is less than the upper limit value and greater than or equal to the lower limit value, then the value of the interpolation parameter function does not need to be corrected. For example, in the embodiment shown in FIG. 3 , the method of correcting the value of the interpolation parameter function C _m (g) can be represented by the following formula:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

That is to say, the above- _mentioned upper limit and lower limit are respectively 1 and 0.5 in the embodiment of FIG. ) is greater than or equal to 1, then the processing unit 102 will modify the value of the interpolation parameter function C _m (g) to 1, and if the value of the interpolation parameter function C _m (g) is less than 0.5, the processing unit 102 will interpolate The value of the parametric function C _m (g) is corrected to 0.5. It should be noted that the upper limit and lower limit of the formula (3) are only exemplary embodiments, and are not limited thereto. The upper limit and the lower limit can be adjusted according to the actual noise interference, for example, the upper limit and the lower limit can be adjusted according to the frequency of the original voice signal and the sampling frequency of the sampling unit.

After obtaining the value of the interpolation parameter function, the processing unit 102 can calculate the interpolation value between two adjacent sampling points in the original down-frequency signal frame according to the interpolation parameter function. Taking the embodiment of Fig. 3 as an example, the interpolation point s m (4n+2) between the sampling points s _m (4n) and s _m (4n+4) in the original down-frequency signal frame Wm and the interpolation point s _m (4n+2) between the sampling points The interpolation point s _m (4n+6) between the points s _m (4n+4) and s _m (4n+8) can be expressed as follows:

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In formula (3) and formula (4), n is 0 or a positive even number.

Similarly, the part of square dots in Fig. 3 can also be obtained by interpolation operation of hollow circle dots. For example, the processing unit 102 can calculate according to the trigonometric function relationship between the sampling point s _m (4n), the interpolation point s _m (4n+2) and the sampling point s _m (4n+4) in the original down-frequency signal frame The interpolation parameter function C' _m (n) is obtained, and its corresponding interpolation parameter function C' _m (n) can be shown in the following formula within the time range of the original down-frequency signal frame Wm:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 4</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Where n is 0 or a positive even number, the correction method of the value of the interpolation parameter function C' _m (n) can be expressed by the following formula:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 0.85</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0.85</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0.85</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

The interpolation point s _m (4n+1) between the sampling point s _m (4n) and the interpolation point s _m (4n+2) and the interpolation point s _m ( The interpolation point s _m (4n+3) between 4n+2) and the sampling point s _m (4n+4) can be expressed as follows:

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In addition, the processing unit 102 can be based on the trigonometric function between the sampling point s _m (4n+4), the interpolation point s _m (4n+6) and the sampling point s _m (4n+8) in the original down-converted signal frame relationship to obtain the interpolation parameter function C" _m (n), and its corresponding interpolation parameter function C " _m (n) in the time range of the original down-frequency signal frame Wm can be shown in the following formula:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 4</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

Wherein n is 0 or a positive even number. In addition, the correction mode of the value of the interpolation parameter function C" _m (n) can be expressed by the following formula:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 0.85</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0.85</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0.85</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

In the original down-frequency signal frame Wm, the interpolation point s _m (4n+5) between the sampling point s _m (4n+4), the interpolation point s _m (4n+6) and the interpolation point s _m (4n+6), the interpolation point s _m (4n+7) between the sampling point s _m (4n+8) can be shown in the following formula respectively:

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

By analogy, the interpolation value between the sampling points or the interpolation value between the sampling point and the interpolation point in other original down-frequency signal frames can also be obtained in the same way, and those skilled in the art should be able to follow the teachings of the above-mentioned embodiments Its implementation manner is deduced, so it will not be repeated here.

As mentioned above, the present embodiment uses trigonometric functions to estimate the interpolation value between the sampling points (or the interpolation value between the sampling point and the interpolation point), and calculates the values of two adjacent samples in the original down-frequency signal frame according to the interpolation parameter function. The interpolation value between points (or the interpolation value between adjacent sampling points and interpolation points) is used as the sampling value of a new sampling point between known sampling points in the down-frequency signal. Since the characteristics of the trigonometric function are similar to the characteristics of the sound signal, compared with the prior art that simply uses the arithmetic mean to calculate the interpolation value, the calculation method of this embodiment can obtain a more accurate interpolation value, and can effectively Avoid signal distortion in the voice signal after frequency reduction.

In addition, each of the above-mentioned original down-frequency signal frames may include p sampling points (wherein p is a positive integer, and in this embodiment, P may be equal to 4N-3, and N is a positive integer greater than 1), and the processing unit 102 may convert the The sampling point number corresponding to the middle sampling point of the m-1 updated down-frequency signal frame in the m-1 original down-frequency signal frame is used as the phase reference sampling point number, and is determined according to the phase reference sampling point number in the m-th The first sampling point in the original down-frequency signal frame that matches the phase of the sampling point corresponding to the phase reference sampling point number, and the q consecutive sampling points from this first sampling point are taken as the mth updated down-frequency signal frame (wherein q is a positive integer, in this embodiment q can be equal to 2N-1, and N is a positive integer greater than 1), so that the middle sampling point of the m-1th update down-frequency signal frame is the same as the mth The phase matching of the initial sampling points of the updated down-frequency signal frame, where m is a positive integer greater than 1. In this way, when the m-1th update down-frequency signal frame and the m-th update down-frequency signal frame perform 50% signal frame aliasing (that is, the m-1th update down-frequency signal frame and the mth update The down-converted signal frames respectively have 50% overlap), the phase mismatch can be greatly reduced, and the signal distortion can be improved.

In detail, the processing unit 102 may accumulate the first count value and the second count value according to the sampling value of the sampling point in the m-th original down-frequency signal frame, wherein when the processing unit 102 counts to a sampling point whose corresponding sampling value is 0 or When there is at least one sampling point adjacent to the sampling point with a sampling value of 0 (for example, the adjacent previous and subsequent sampling points, but not limited thereto), the corresponding first count value or the second count value is reset to zero. Specifically, the method of accumulating the count value above can be expressed according to the following formulas (13)-(16):

${\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; or</span>}\mathrm{<span\; class="notranslate">\; 7</span>}\\ {\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; else</span>}\end{array}\right.-<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; PN</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; or</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 3</span>}\\ {\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; else</span>}\end{array}\right.-<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 16</span>}<span\; class="notranslate">\; )</span>$

Where m is a positive integer greater than 1, n=0,1,2,...,4N-4, N is a positive integer greater than 1, s _m (n) is the sampling number n in the mth original down-frequency signal frame The sampling value of the point, PN _m (n) is to convert the sampling value s _m (n) into a value represented by "10", "3" or "0", where PN _m (-1)=PN _m (0) . is the first count value corresponding to the sampling point numbered n in the mth original down-frequency signal frame, and Be the second count value corresponding to the sampling point numbered n in the mth original down-frequency signal frame, wherein and From formula (1), (2) we can know For the cumulative count value corresponding to the down-frequency signal in the positive half cycle, and It is the accumulative count value corresponding to the down-frequency signal in the negative half cycle. As shown in formulas (1) to (4), in this embodiment, the sampling values when the sampling value s _m (n) is greater than 0, when s _m (n) is equal to 0, and when s _m (n) is less than 0 are respectively set as 10, 3, 0, counting the first count value time When it is equal to 10 or 7, the corresponding first count value is reset to zero, and in addition, the second count value is counted time When it is equal to -10 or -3, the corresponding second count value is reset to zero. Since the sampling value when the sampling value s _m (n) is equal to 0 is set to 3, so A position equal to 10, 7, -10 or -3 will appear at the sampling point adjacent to the sampling point corresponding to when the sampling value s _m (n) is equal to 0.

The processing unit 102 may calculate the first count value or the second count corresponding to the sampling point corresponding to the phase reference sampling point number obtained in the m-1th original down-frequency signal frame in the m-th original down-frequency signal frame value (which is obtained by counting by the processing unit 102 in the m-1th original down-frequency signal frame, and its counting method is the same as the counting method of the above-mentioned processing unit 102 in the m-th original down-frequency signal frame) as a reference value, And according to this reference value, determine the first sampling point of the phase matching of the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame. For example, the processing unit 102 may determine whether the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the phase number in the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the reference sampling point number can be represented by the following formula (17):

${\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; COt</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 17</span>}<span\; class="notranslate">\; )</span>$

in is the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame, and is the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame.

If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame is less than or equal to the corresponding sampling point corresponding to the phase reference sampling point number in the m-th original down-frequency signal frame The processing unit 102 takes the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame as a reference value, and takes the m-th original down-frequency The first sampling point in the corresponding sampling points when the first count value in the signal frame is equal to the reference value is taken as the first sampling point, which can be represented by the following formulas (18), (19):

${\mathrm{<span\; class="notranslate">\; no</span>}}_{{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; S</span>}}\\ \mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; else</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 18</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; no</span>}}_{{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; min</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 19</span>}<span\; class="notranslate">\; )</span>$

By formula (18), (19), when the first counter value corresponding to the sampling point of number n in the mth original down-frequency signal frame is equal to the phase reference sampling point in the m-1th original down-frequency signal frame When the first count value corresponding to the sampling point corresponding to the serial number, equal to the number n corresponding to the sampling point, otherwise It is equal to 4N-4. and then in all The minimum value in , which represents the number of the first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number in the m-th original down-frequency signal frame, and this sampling point is used as the m-th update down-frequency The initial sampling point of the frequency signal frame.

Conversely, if the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is not less than or equal to the phase reference sampling point in the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the point number (that is, the formula (17) is not established), then the processing unit 102 will correspond to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame The second count value of the second count value is used as the reference value, and the first sampled sampling point in the corresponding sampling points when the second count value in the mth original down-frequency signal frame is equal to the reference value is taken as the first sampling point, which can be as follows Formulas (20), (21) express:

${\mathrm{<span\; class="notranslate">\; no</span>}}_{{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; S</span>}\\ \mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; else</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; no</span>}}_{{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; min</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{{\mathrm{<span\; class="notranslate">\; Cot</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; one</span>}<span\; class="notranslate">\; )</span>$

By formula (20), (21), when the second count value corresponding to the sampling point of number n in the mth original down-frequency signal frame is equal to the phase reference sampling point in the m-1th original down-frequency signal frame When the second count value corresponding to the sampling point corresponding to the serial number, equal to the number n corresponding to the sampling point, otherwise It is equal to 4N-4. and then in all The minimum value in , which represents the number of the first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number in the m-th original down-frequency signal frame, and this sampling point is used as the m-th update down-frequency The initial sampling point of the frequency signal frame.

For example, assume that each original down-frequency signal frame WL1~WL4 in FIG. 2 includes 401 sampling points respectively, that is, each original down-frequency signal frame WL1~WL4 includes 401 sampling points such as 0, 1, 2, ..., 400, etc. a sampling point. The first count value corresponding to the phase reference sampling point number (which is 188) corresponding to the intermediate sampling point of the update down-frequency signal frame WL2' in the original down-frequency signal frame WL2 Less than or equal to the second count value corresponding to the phase reference sampling point number sampling point corresponding to the intermediate sampling point of the update down-frequency signal frame WL2' in the original down-frequency signal frame WL2 And the first count value corresponding to the middle sampling point of the original down-frequency signal frame WL2 (that is, the sampling point numbered 188 in the original down-frequency signal frame WL2) for 18.

In order to find the initial sampling point for updating the down-frequency signal frame WL3', the processing unit 102 can count the first count value in the original down-frequency signal frame WL3 When it is equal to 18, the numbering of the corresponding sampling point (due to the first counter value corresponding to the sampling point numbered as 188 in the original down-frequency signal frame WL2 less than the corresponding second count value So with the first count value as a base value). Fig. 4 shows the schematic diagram of the original down-frequency signal frame WL3 of an embodiment of the present invention, as shown in Fig. 4, in the embodiment of Fig. 4, the first count value in the original down-frequency signal frame WL3 When equal to 18, the number of the corresponding sampling point (that is, not equal to 0 value) includes sampling points numbered 20, 40, 63, 79, ..., 300, 325, 342, 363, 392, etc., wherein the sampling point numbered 20 is the first count value in the original down-frequency signal frame WL3 Equal to the sampling point of the earliest sampling in the corresponding sampling points when the reference value (its value is 18) in the original down-frequency signal frame WL2, so equal to 20, the processing unit 102 takes it as the initial sampling point for updating the down-frequency signal frame WL3', and takes the continuous 201 sampling points from the sampling point number 20 in the original down-frequency signal frame WL3 as the update down-frequency signal frame WL3 'The sampling point. As shown in Figure 2, the update down-frequency signal frame WL3' includes sampling points numbered 20 to 220 in the original down-frequency signal frame WL3, wherein number 120 (which is the mid-sample point of the update down-frequency signal frame WL3' in the original down-frequency signal frame WL3 The corresponding sampling point number in the signal frame WL3 ) can be used as the phase reference sampling point number, which is used as a basis for finding and updating the initial sampling point of the down-frequency signal frame WL4 ′. Similarly, the initial sampling point for updating the down-frequency signal frame WL4' can also be obtained in a similar manner, so details will not be repeated here.

It is worth noting that since the original down-frequency signal frame WL1 is the first original down-frequency signal frame, the sampling points for updating the down-frequency signal frame WL1' can be 201 consecutive samples randomly selected from the original down-frequency signal frame WL1 Sampling points (in this embodiment, sampling points numbered 100 to 300), and according to the number corresponding to the intermediate sampling point in the original down-frequency signal frame WL1 and the updated down-frequency signal frame WL1' as the phase reference sampling point number ( In this embodiment, it is the sampling point numbered 200). In this embodiment, the number corresponding to the first sampling point in the original down-frequency signal frame WL2 that matches the phase of the middle sampling point of the original down-frequency signal frame WL1 is 188, wherein the first sampling point (number 188 The method of obtaining the sampling point) is similar to the above-mentioned embodiment, and those skilled in the art should be able to deduce its implementation method based on the above content, so it is not repeated here.

After obtaining the updated down-frequency signal frame, the processing unit 102 can perform 50% aliasing on the adjacent updated down-frequency signal frame to generate an overlapping voice signal, because the intermediate sampling points of each updated down-frequency signal frame The phase is matched with the initial sampling point of the next updated down-frequency signal frame, so the signal distortion caused by the phase mismatch when the signal frames overlap will be greatly improved. In addition, in some embodiments, after obtaining the updated down-frequency signal frame corresponding to each original down-frequency signal frame, the down-frequency signal can be multiplied by a Hamming window (Hamming Window), so as to increase the left and right ends of the updated down-frequency signal frame. continuity. As shown in Figure 2, after multiplying the down-frequency signal SL' including the updated down-frequency signal frames WL1'～WL4' by the Hamming window, the updated down-frequency signal SH including the down-frequency signal frames WH1～WH4 can be obtained, and then Then, aliasing is performed on the updated down-frequency signal frames WH1-WH4 to obtain the overlapping voice signal SO.

FIG. 5 is a schematic flowchart of a voice signal processing method according to an embodiment of the present invention, please refer to FIG. 5 . It can be known from the above embodiments that the speech signal processing method of the speech signal processing device may include the following steps. First, the original speech signal is sampled to generate a sampled speech signal (step S502). Next, the speech signal is down-sampled to generate a down-converted signal including a sequence of original down-converted signal frames (step S504 ), wherein the frequency of the down-converted signal can be, for example, a quarter of the sampled speech signal. Wherein, some sampling points in the down-frequency signal can be obtained through interpolation. FIG. 6 is a schematic flowchart of a voice signal processing method according to another embodiment of the present invention. As shown in FIG. 6 , it can be seen from the above embodiment that the method for calculating an interpolation point by a voice signal processing device may include the following steps. First, calculate the value of the interpolation parameter function corresponding to each original down-frequency signal frame according to three consecutive sampling values in each original down-frequency signal frame (step S602), wherein the interpolation parameter function can be based on the values in each original down-frequency signal frame It is calculated from the trigonometric function relationship between three consecutive sampling values, and the interpolation parameter function can be a trigonometric function. Afterwards, it can then be judged whether the value of the interpolation parameter function is less than the upper limit value and greater than or equal to the lower limit value (step S604), if the value of the interpolation parameter function is not less than the upper limit value or not greater than or equal to the lower limit value, then the correction internal Interpolate the value of the parameter function (step S606) to remove unnecessary noise. Wherein the upper limit and the lower limit can be adjusted according to the situation of actual noise interference, for example, the upper limit and the lower limit can be adjusted according to the frequency of the original speech signal and the sampling frequency of the sampling unit, and the value of the interpolation parameter function The correction method can be, for example, when the value of the interpolation parameter function is greater than or equal to the upper limit value, the value of the interpolation parameter function is corrected to the upper limit value, and when the value of the interpolation parameter function is less than the lower limit value, the value of the interpolation parameter function is The value of the function is corrected to the lower limit value. After the value of the interpolation parameter function is corrected, the interpolation value between two adjacent sampling points in each original down-frequency signal frame can be calculated according to the value of the interpolation parameter function corresponding to each original down-frequency signal frame (step S608 ). On the contrary, if the value of the interpolation parameter function is less than the upper limit and greater than or equal to the lower limit, then go directly to step S608 to calculate the interpolation value between two adjacent sampling points in each original down-frequency signal frame.

Please refer to Fig. 5 again, after step S504, it can be determined according to the phase reference sampling point number corresponding to the middle sampling point of the m-1th update down-frequency signal frame in the m-1th original down-frequency signal frame and the m-1th update down-frequency signal frame The first sampling point (step S506) of the phase matching of the sampling point corresponding to the phase reference sampling point number in the m original down-frequency signal frame, wherein the length of each updated down-frequency signal frame is equal to the length of each original down-frequency signal frame One-half of the phase reference sampling point number is the number of the sampling point corresponding to the middle sampling point in the m-1th original down-frequency signal frame and the m-1th updated down-frequency signal frame, and m is greater than A positive integer of 1. Afterwards, the continuous q sampling points from the first sampling point phase-matched with the phase reference sampling point number are used as the sampling points of the mth update down-frequency signal frame (step S508), where q is a positive integer. Finally, the adjacent updated down-frequency signal frames are aliased again to generate an overlapping speech signal (step S510 ), wherein two adjacent updated down-frequency signal frames may respectively have a 50% overlapping section, for example.

FIG. 7 is a schematic flowchart of a voice signal processing method according to another embodiment of the present invention, please refer to FIG. 7 . In detail, step S506 of the embodiment in FIG. 5 may include steps S702 to S706 in this embodiment, that is, to first accumulate the first count value and the second count value according to the sampling value of the sampling point in the mth original down-frequency signal frame. When counting to a sampling point corresponding to a sampling value of 0 or at least one sampling point adjacent to a sampling point with a sampling value of 0, the corresponding first counting value or second counting value is reset to zero (step S702) , then the first count value or the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame is used as the reference value (step S704), and then the mth value is determined according to the reference value The first sampling point of the phase matching of the sampling point corresponding to the phase reference sampling point number in the original down-frequency signal frame (step S706). Furthermore, step S704 may include firstly determining whether the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the frequency signal frame (step S708). If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is less than or equal to the value corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame The second count value corresponding to the sampling point, the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is used as a reference value (step S710), in this case Next, in step S706, the earliest sampled sampling point among the corresponding sampling points when the first count value in the mth original down-frequency signal frame is equal to the reference value can be used as the phase reference sampling point in the m-th original down-frequency signal frame The first sample point whose number corresponds to the phase match of the sample point. Conversely, if the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is not less than or equal to the phase reference sampling point in the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the point number, the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is used as a reference value (step S712) , in this case, in step S706, the earliest sampled sampling point among the sampling points corresponding to when the second count value in the mth original down-frequency signal frame is equal to the reference value can be used as the first sampling point in the m-th original down-frequency signal frame and The first sampling point of the phase matching of the sampling point corresponding to the phase reference sampling point number.

To sum up, in the embodiment of the present invention, the m-1th original down-frequency signal frame is determined based on the phase reference sampling point number corresponding to the middle sampling point of the m-1th updated down-frequency signal frame. The first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number in the original down-frequency signal frame, and the continuous q from the first sampling point phase matching of the sampling point corresponding to the phase reference sampling point number The sampling point is used as the sampling point of the mth update down-frequency signal frame, so that when the sampled speech signal is further down-frequency (for example, the frequency is reduced to a quarter), the phase when the signal frame overlaps can still be effectively improved Signal distortion caused by mismatch.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (17)

1. A voice signal processing device, characterized in that, comprising: A processing unit for down-sampling a speech signal to generate a down-frequency signal comprising a sequence of original down-frequency signal frames, and generating corresponding updated down-frequency signal frames according to the original down-frequency signal frames, wherein each of the original down-frequency signal frames The down-frequency signal frame includes p sampling points, and the processing unit is based on a phase reference sampling point corresponding to the middle sampling point of the m-1th updated down-frequency signal frame in the m-1th original down-frequency signal frame The number determines the first sampling point phase-matched with the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame, and the first sampling point phase-matching from the sampling point corresponding to the phase reference sampling point number The q consecutive sampling points from the first sampling point are used as the sampling points of the m-th update down-frequency signal frame, and the adjacent update down-frequency signal frames are aliased to generate an overlapping voice signal, wherein the phase The reference sampling point number is the numbering of the sampling point corresponding to the middle sampling point of the m-1th update down-frequency signal frame in the m-1 original down-frequency signal frame, p, q are positive integers, m is a positive integer greater than 1. 2. The speech signal processing device according to claim 1, wherein the frequency of the down-frequency signal is 1/4 of the sampled speech signal, and the length of each of the updated down-frequency signal frames is equal to each of the down-frequency signal frames. half of the length of the original down-frequency signal frame. 3 . The speech signal processing device according to claim 1 , wherein the two adjacent update down-frequency signal frames each have a 50% overlapping section. 4 . 4. The speech signal processing device according to claim 3, wherein the processing unit also accumulates a first count value and a second count value according to the sampling value of the sampling point in the mth original down-frequency signal frame. A counting value, wherein when counting to a sampling point corresponding to a sampling value of 0 or at least one sampling point adjacent to a sampling point having a sampling value of 0, the corresponding first counting value or the second counting value is reset to zero , using the first count value or the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame as a reference value, and according to the The reference value determines the first sampling point whose phase matches the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame. 5. The speech signal processing device according to claim 4, characterized in that, the processing unit also judges the position of the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame Whether the corresponding first count value is less than or equal to the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame, if the The first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is less than or equal to the phase in the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the reference sampling point number is the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame A count value is used as the reference value, and the earliest sampled sampling point among the sampling points corresponding to when the first count value in the mth original down-frequency signal frame is equal to the reference value is used as the mth The first sampling point that matches the phase of the sampling point corresponding to the phase reference sampling point number in the original down-frequency signal frame, if the m-1th original down-frequency signal frame matches the phase reference sampling point The first count value corresponding to the sampling point corresponding to the point number is not less than or equal to the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame. Count value, the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 original down-frequency signal frame is used as the reference value, and the m-th The earliest sampled sampling point among the sampling points corresponding to when the second count value in the original down-frequency signal frame is equal to the reference value is used as the number corresponding to the phase reference sampling point number in the mth original down-frequency signal frame The sampling point phase matches the first sampling point. 6. The speech signal processing device according to claim 1, wherein the processing unit further multiplies the down-frequency signal by a Hamming window. 7. The speech signal processing device according to claim 1, wherein the processing unit is also calculated according to three consecutive sampling values corresponding to each of the original down-frequency signal frames in each of the original down-frequency signal frames. value of the interpolation parameter function, and calculate the interpolation value between two adjacent sampling points in each of the original down-frequency signal frames according to the value of the interpolation parameter function corresponding to each of the original down-frequency signal frames. 8. The speech signal processing device according to claim 7, wherein the processing unit further judges whether the value of the interpolation parameter function is less than an upper limit and greater than or equal to a lower limit, if the interpolation The value of the parameter function is not less than the upper limit value or not greater than or equal to the lower limit value, and the value of the interpolation parameter function is corrected, wherein if the value of the interpolation parameter function is greater than or equal to the upper limit value, the The value of the interpolation parameter function is corrected to the upper limit value, and if the value of the interpolation parameter function is smaller than the lower limit value, the value of the interpolation parameter function is corrected to the lower limit value. 9. The speech signal processing device according to claim 8, wherein the sampled speech signal is generated by sampling an original speech signal, and the upper limit and the lower limit are associated with the original speech The frequency of the signal is related to the sampling frequency at which the original speech signal is sampled. 10. The speech signal processing device according to claim 7, characterized in that, the processing unit also calculates each of the original down-frequency signals according to the trigonometric relationship between the three consecutive sampling values in each of the original down-frequency signal frames. An interpolation parameter function corresponding to the frequency signal frame, wherein the interpolation parameter function is a trigonometric function. 11. A voice signal processing method, characterized in that, comprising: down-sampling the speech signal to generate a down-converted signal comprising a sequence of original down-converted signal frames, wherein each of the original down-converted signal frames comprises p sampling points, where p is a positive integer; According to a phase reference sampling point number corresponding to the middle sampling point in the m-1th original down-frequency signal frame and the m-1th updated down-frequency signal frame The first sampling point of the phase matching of the sampling point corresponding to the phase reference sampling point number, wherein m is a positive integer greater than 1, and the phase reference sampling point number is in the m-1th original down-frequency signal frame The serial number of the sampling point corresponding to the middle sampling point of the m-1th updated down-frequency signal frame; and Taking the continuous q sampling points from the first sampling point phase-matched with the phase reference sampling point number as the sampling point of the mth update down-frequency signal frame, where q is a positive integer; as well as Adjacent frames of the updated down-converted signal are aliased to generate an overlapping speech signal. 12. The speech signal processing method according to claim 11, characterized in that, the basis corresponds to the middle sampling point of the m-1th update down-frequency signal frame in the m-1th original down-frequency signal frame A phase reference sampling point number determines the first sampling point phase-matched with the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame, including: Accumulate a first count value and a second count value according to the sampling value of the sampling point in the mth original down-frequency signal frame, wherein when counting to a sampling point corresponding to a sampling value of 0 or a sampling value corresponding to a sampling value of 0 When at least one sampling point adjacent to the point is selected, the corresponding first count value or the second count value is reset to zero; using the first count value or the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame as a reference value; and The first sampling point for phase matching of the sampling point corresponding to the phase reference sampling point number in the m th original down-frequency signal frame is determined according to the reference value. 13. The speech signal processing method according to claim 12, characterized in that, the said mth original down-frequency signal frame corresponding to the sampling point corresponding to the phase reference sampling point number The step of using a count value or the second count value as the reference value includes: Judging whether the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the phase reference sampling point number; If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame is less than or equal to the number in the m-1th original down-frequency signal frame The second count value corresponding to the sampling point corresponding to the phase reference sampling point number is the corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame The first count value is used as the reference value; and If the first count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1 th original down-frequency signal frame is not less than or equal to the m-1 th original down-frequency signal frame In the second count value corresponding to the sampling point corresponding to the phase reference sampling point number, the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame The corresponding second count value is used as the reference value. 14. The speech signal processing method according to claim 13, wherein, if the said m-1th original down-frequency signal frame is corresponding to the sampling point corresponding to the phase reference sampling point number The first count value is less than or equal to the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the m-1th original down-frequency signal frame, and the voice signal processing method includes: Taking the earliest sampled sampling point among the sampling points corresponding to when the first count value in the mth original down-frequency signal frame is equal to the reference value as the first sampling point in the m-th original down-frequency signal frame and the The sampling point number corresponding to the phase reference sampling point matches the first sampling point in phase. 15. The speech signal processing method according to claim 13, wherein, if the mth original down-frequency signal frame is corresponding to the sampling point corresponding to the phase reference sampling point number A count value is not less than or equal to the second count value corresponding to the sampling point corresponding to the phase reference sampling point number in the mth original down-frequency signal frame, and the speech signal processing method includes: Taking the earliest sampled sampling point among the sampling points corresponding to when the second count value in the mth original down-frequency signal frame is equal to the reference value as the first sampling point in the m-th original down-frequency signal frame and the The sampling point number corresponding to the phase reference sampling point matches the first sampling point in phase. 16. The speech signal processing method according to claim 11, characterized in that, comprising: Calculate the value of the interpolation parameter function corresponding to each of the original down-frequency signal frames according to three consecutive sampling values in each of the original down-frequency signal frames; judging whether the value of the interpolation parameter function is less than an upper limit and greater than or equal to a lower limit, if the value of the interpolation parameter function is not less than the upper limit or not greater than or equal to the lower limit, modify the the value of the interpolation parameter function; and An interpolation value between two adjacent sampling points in each down-frequency signal frame is calculated according to the value of the interpolation parameter function corresponding to each down-frequency signal frame. 17. The speech signal processing method according to claim 16, wherein if the value of the interpolation parameter function is greater than or equal to the upper limit value, the value of the interpolation parameter function is corrected to the Upper limit value, if the value of the interpolation parameter function is less than the lower limit value, modify the value of the interpolation parameter function to the lower limit value, wherein the sampled speech signal is obtained by sampling an original speech signal Therefore, the upper limit value and the lower limit value are related to the frequency of the original speech signal and the sampling frequency for sampling the original speech signal.