JP2002043874A - Electronic volume with automatic adjustment function - Google Patents

Abstract

(57) [Problem] To provide an electronic volume with an automatic adjustment function capable of appropriately controlling a volume value according to a bit shift operation. SOLUTION: A volume control means 4 operated by a user via a microcomputer to control a volume value of an electronic volume main body 1, and audio data to be applied to the electronic volume main body 1 are inputted to perform a bit shift operation of the audio data. Bit shifter to perform (gain adjustment unit)
And a compensation control input for compensating for a gain variation due to the bit shift operation of the bit shift means 8 in accordance with the bit shift operation of the bit shift means 8 from the bit shift means 8 to the volume control means 4. I did it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an "electronic volume with an automatic adjustment function" that can control a volume value according to a signal level value in audio equipment such as a home (stationary type) and a vehicle. Things.

[0002]

2. Description of the Related Art An existing electronic volume is controlled via a dedicated serial interface every time a microcomputer in a system reads a volume value set by a user once and updates the set value.

FIG. 6 is a block diagram showing the overall configuration of an electronic volume according to the prior art. In the figure, 1 is an electronic volume main body, 2 is a microcomputer, and 3 is a key switch. When a control input as a volume operation by a user is applied to the key switch 3, a serial signal for volume value control is applied to the electronic volume main body 1 via the microcomputer 2 which receives information on the key switch 3.

As described above, the conventional device lacks real-time performance / applicability to the system due to the following problems (1) and (2) because it is a device that operates passively waiting for control from the microcomputer. . (1) Time is required for control. (2) I am not good at complicated control.

Conventionally, in digital audio,
Audio Digital Signal Processor (Digi
When operating frequency characteristics such as an equalizer using a tal signal processor (hereinafter referred to as a DSP), since an increase in gain causes an overflow, gain attenuation (scaling) is performed by a bit shift operation from the beginning and audio data is processed. Had a margin of several bits on the upper side.

However, in the above-described method, scaling is performed regardless of ON / OFF of an audio function such as an equalizer, so that the effective bit length of audio data is reduced, causing deterioration of S / N performance. .
DSP and D / A having a bit length larger than the bit length of input data in order to guarantee the accuracy of audio data
A converter (hereinafter, referred to as DAC) had to be prepared.

[0007]

In order to solve such a situation, it is conceivable to secure valid bits by a bit shift operation when an audio function such as an equalizer is in an OFF state. However, since the bit shift operation performed here involves a change in gain,
It is necessary to prevent gain fluctuation due to the bit shift operation and appropriately control the volume value.

An object of the present invention is to provide an electronic volume with an automatic adjustment function that can appropriately control a volume value according to a bit shift operation.

[0009]

According to the first aspect of the present invention, there is provided an electronic volume with an automatic adjustment function, wherein the volume is controlled by a user through a microcomputer to control a volume value of the electronic volume main body; Bit shift means for inputting audio data applied thereto and performing a bit shift operation of the audio data, and compensating for a gain variation due to the bit shift operation of the bit shift means according to the bit shift operation of the bit shift means. The compensation control input is applied from the bit shift means to the volume control means.

In an electronic volume with an automatic adjustment function according to a second aspect of the present invention, a volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and a digital audio applied to the electronic volume main body. Bit shift means for inputting data and performing a bit shift operation of the digital audio data, a digital signal processor for processing digital audio data input to the bit shift means, and converting an output of the bit shift means into an analog signal D / A converted and applied to the electronic volume body
A digital signal processor, a bit shift means, a D / A converter, and a volume control means are integrally integrated as an integrated circuit, and the bit shift is performed in accordance with a bit shift operation of the bit shift means. A compensation control input for compensating for a gain variation due to a bit shift operation of the means is applied from the bit shift means to the volume control means.

In the electronic volume with an automatic adjustment function according to a third aspect of the present invention, a volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and audio data applied to the electronic volume main body. And a bit shift means for performing a bit shift operation for gaining effective bits of audio data, wherein a gain variation due to the bit shift operation of the bit shift means is increased in accordance with an increase in gain due to the bit shift operation of the bit shift means. The compensation control input for compensation is applied from the bit shift means to the volume control means.

According to a fourth aspect of the present invention, there is provided an electronic volume with an automatic adjustment function, the volume control means being operated by a user via a microcomputer to control a volume value of the electronic volume main body, and audio data applied to the electronic volume main body. And a bit shift means for performing a bit shift operation of the audio data, wherein an ON / O of an audio function for performing a gain operation according to a frequency from a use state of upper bits in the audio data is provided.
A confirmation means for confirming the FF state is provided, and when the bit shift means performs the bit shift operation in the audio function OFF state confirmed by the confirmation means, the bit is transmitted in accordance with the bit shift operation of the bit shift means. A compensation control input for compensating for a gain variation due to a bit shift operation of the shift means is applied from the bit shift means to the volume control means.

In the electronic volume with an automatic adjusting function according to a fifth aspect of the present invention, a volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and audio data applied to the electronic volume main body. And a bit shift means for performing a bit shift operation of the audio data, and performing an ON / OFF of an audio function for performing a gain operation according to a frequency.
A detection means for detecting the F state by the microcomputer based on key switch information input by a user is provided, and the bit shift means performs a bit shift operation in an OFF state of the audio function detected by the detection means. And a compensation control input for compensating for a gain variation caused by the bit shift operation of the bit shift means in response to the bit shift operation of the bit shift means. .

In an electronic volume with an automatic adjusting function according to a sixth aspect of the present invention, a volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and audio data applied to the electronic volume main body. And a bit shift means for performing a bit shift operation of the audio data, wherein when the audio data value is at full scale, the bit shift operation of the bit shift means lowers the gain, and the bit shift means A compensation control input for compensating for a gain change caused by the bit shift operation of the bit shift means in response to the bit shift operation is applied from the bit shift means to the volume control means.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An embodiment according to the present invention will be described with reference to FIGS. Figure 1
FIG. 1 is a block diagram showing an overall configuration of an electronic volume according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing the necessity of auto scaling. FIG. 3 is an explanatory diagram showing a configuration related to auto scaling in the embodiment according to the present invention. FIG. 4 is an explanatory diagram showing an overflow limiter according to an embodiment of the present invention in comparison with a conventional technology. FIG. 5 is an explanatory diagram showing the volume switching operation at the time of zero crossing in the embodiment according to the present invention in comparison with the related art.

According to the embodiment of the present invention, there is provided a checking means for checking the presence or absence of scaling by monitoring audio data, and a bit shift means having a gain adjustment function (bit shifter) for digital data, so that an analog signal is directly provided. This realizes a system in which the volume for use can be controlled by volume control means for controlling the volume value of the electronic volume body (see FIG. 1). This system has made it possible to realize "adaptability to the system" and "real-time control" in which the volume can be controlled according to the value of audio data.

In FIG. 1, 1 is an electronic volume main body,
2 is a microcomputer, 3 is a key switch, 4 is a volume control means, 5 is a digital data input terminal, 6 is an audio DSP, 7 is a confirmation means comprising a data value monitor, and 8 is a bit shifter comprising a bit shifter (gain adjustment unit). Means 9 is an audio DAC, and 10 is an audio data output terminal. Then, audio DSP: 6, data value monitor 7, bit shift means 8, audio DAC:
9, the electronic volume main body 1, the volume control means 4, and the microcomputer 2 are all integrated into a single-chip integrated circuit.

Digital data consisting of a PCM signal is applied to a digital data input terminal 5, and this digital data is subjected to signal processing by an audio DSP 6 and passed through a check means 7 consisting of a data value monitor to a bit shifter (gain adjusting section). ) Is supplied to the bit shift means 8. The output of the bit shift means 8 is converted into an analog signal by the audio DAC 9 and is derived as analog audio data from the audio data output terminal 10 via the electronic volume main unit 1.

The volume operation by the user is executed by performing an input operation on the key switch 3 and giving desired information. The information of the key switch 3 is read by the microcomputer 2, and a control signal is applied to the volume control means 4 based on this information, and the volume value in the electronic volume main body 1 is set to a desired value required by the user.

Also, when an equalizer operation is performed by the user and the equalizer function is turned on, the key switch 3 is given the desired information and is executed under the processing of the microcomputer 2. The microcomputer 2
Audio DSP: 6 based on information of key switch 3
And perform the equalizer function.

Here, the necessity of auto scaling is
FIG. 2 will be described. FIG. 2A is a curve diagram illustrating a gain setting corresponding to a frequency in a three-band graphic equalizer. FIG. 2B is an explanatory diagram showing a bit shift operation on audio data. FIG.
As shown in (a), when the gain amplification in the equalizer is a maximum of +12 dB, the audio DS
The audio data as the output of P: 6 is shown in FIG.
As shown in ( ² ), the "actual value" is shifted downward by 2 bits from the "original value" to be -12 dB (= 2 ^-2 times). This shift operation is performed when the equalizer function is turned ON / OF.
Actually, it is performed irrespective of the F state. In the OFF state of the equalizer function, the actual use bits of the audio data are such that the “actual value” is n−2 bits with respect to n bits of “original value” And the S / N performance deteriorates.
Therefore, in the OFF state of the equalizer function, so-called auto scaling, in which the shift operation to the lower bits is returned to the original state by the shift operation to the upper bits, is useful.

The bit shift operation in the embodiment of the present invention shown in FIG. 1 is as follows. The checking means 7 comprising a data value monitor performs a monitoring operation on digital data output from the audio DSP 6, and performs an equalizer function for performing a gain operation according to the frequency from the use state (degree of data change) of the upper bits. Check the ON / OFF status of the audio function [Figure 1:
Function (1)]. If the audio function such as the equalizer function is ON, the upper bits are used reliably,
If the audio function such as the equalizer function is in the OFF state, the upper bits are not used.

When it is confirmed by the confirmation means 7 comprising a data value monitor that the audio function such as the equalizer function is in the OFF state, as shown in FIGS. 3A and 3B, the bit shifter (gain adjustment unit) By the bit shift operation of the bit shift means 8, a return operation is performed in which the audio data whose upper bits are blank is shifted upward by 2 bits. Since the gain is set to +12 dB (2 bit shift) by this bit shift (return) operation, the bit shift means 8 composed of a bit shifter (gain adjustment unit) must be connected to the microcomputer 2 in synchronization with the bit shift (return) operation. Instead, the control signal is directly sent to the volume control means 4 of the electronic volume main body 1 to adjust the volume value to -12 dB.
Therefore, the gain in the path between the input of the bit shift means 8 composed of a bit shifter (gain adjusting unit) and the output of the electronic volume main body 1 becomes constant irrespective of the bit shift (return) operation of the bit shift means 8, The gain does not change due to the bit shift (return) operation of the means 8.

Here, a control signal for compensating for the gain fluctuation is sent from the bit shift means 8 to the microcomputer 2,
If the microcomputer 2 attempts to control the volume control means 4, not only does the control system in the microcomputer 2 become complicated, but also the control response speed decreases. In the embodiment according to the present invention, audio DSP: 6, data value monitor 7, bit shift means 8, audio DA
C: 9, the electronic volume main body 1, the volume control means 4, and the microcomputer 2 are all integrally integrated as a one-chip integrated circuit.
As described above, the control signal for compensating the gain fluctuation is directly sent from the bit shift means 8 to the volume control means 4 without passing through the microcomputer 2.
The control system in the microcomputer 2 can be simplified, and the control of the volume value can be performed instantaneously.

Japanese Patent Application Laid-Open No. 9-102719 discloses a prior art of this invention as a publication. In this prior art, the above-described control elements are integrally integrated as a one-chip integrated circuit. Not a thing,
In addition, the signal level is corrected by the microcomputer, the time delay cannot be ignored, and it is judged that the practicality is poor in view of the signal followability, which is clearly different from that of the present invention. Is what you do.

Although the ON / OFF state of the audio function such as the equalizer function is performed by the confirmation means 7 comprising a data value monitor, the microcomputer 2 detects the user's operation of the key switch 3 by the microcomputer 2 and performs the operation. Such an ON / OFF state of the audio function can be detected. The information generated on the key switch 3 by the equalizer operation by the user is transmitted to the microcomputer 2.
To detect the ON / OFF state of the audio function.

Also, an appropriate overflow limiter function for signal data as audio data can be performed by the bit shift means 8 comprising a bit shifter (gain adjusting unit). Conventionally, as an overflow limiter that prevents overflow of signal data,
As shown in FIG. 4A, the forced limiter operation is performed in a state where the maximum value is immediately before the positive full scale and the minimum value is immediately before the negative full scale, and the signal data is converted to a value before the full scale. It was something to hold. In this case, distortion of the signal waveform is inevitable. In this embodiment, as shown in FIG. 4 (b), for signal data as audio digital data, a state where the maximum value is positive full scale and a state where the minimum value is negative full scale are detected. When it is in such a state,
That is, when the maximum value is in the positive full scale state, the minimum value is in the negative full scale state, or the maximum value is in the positive full scale state and the minimum value is in the negative full scale state, the bit shifter A bit shift operation for the signal data is performed by the bit shift means 8 comprising a (gain adjusting unit), and the signal data is shifted by one bit (to the gain attenuation side). A margin is generated as digital data for positive full scale and negative full scale. The bit-shifted signal data is converted into an analog signal by the audio DAC 9 (FIGS. 1 and 4B) and input to the electronic volume main unit 1.
Since the gain is set to -6 dB (one bit shift) by the bit shift operation of the bit shift means 8,
In synchronization with the bit shift operation, a bit shift means 8 comprising a bit shifter (gain adjusting unit) directly sends a control signal for compensating for the gain fluctuation to the volume control means 4 of the electronic volume main body 1 without going through the microcomputer 2. , The volume value is adjusted to +6 dB.
Therefore, the gain in the path between the input of the bit shift means 8 composed of a bit shifter (gain adjusting unit) and the output of the electronic volume main body 1 becomes constant irrespective of the bit shift operation of the bit shift means 8. Does not occur due to the bit shift operation.

Further, by using the bit shift means 8 comprising a bit shifter (gain adjusting unit), it is possible to appropriately perform volume switching at the time of zero crossing. As shown in FIG. 5A, at the time of volume switching, when a zero cross point of signal data is detected within a set time, the volume switching operation is performed at the zero cross point. However, when the zero-cross point of the signal data is not detected within the set time and the timeout occurs, it is customary to forcibly switch the volume simultaneously with the zero-cross timeout as shown in FIG. 5B. In this case, occurrence of switching noise is inevitable. In this embodiment, when the zero-cross point of the signal data is not detected within the set time and a timeout occurs,
As shown in FIG. 5C, the bit shift operation is turned on by the bit shift means 8 comprising a bit shifter (gain adjusting unit), and the signal data is bit-shifted to the gain attenuation side. Attenuation of the gain is started by the bit shift operation by the bit shift means 8, and the signal data is rapidly attenuated, so that the zero cross point can be easily created.
By performing volume switching at the zero cross point, generation of noise can be reliably prevented. The waveform operation for creating such a zero-cross point is performed on audio signal data as digital data by the bit shift means 8 comprising a bit shifter (gain adjusting unit). The data is converted to an analog signal by the audio DAC, and is input to the electronic volume main unit 1.
The volume switching at the zero cross point is performed.

In the embodiment according to the present invention, the functions described as the following (A) to (C) are achieved by the above configuration and operation. (A) Auto-scaling function If the audio DSP has a built-in function to set the gain (change the degree of amplification of the signal) according to the frequency of the equalizer or the like, the audio data will be output regardless of whether the function is ON or OFF. Since the gain is set to be low from the beginning, the reduction of the effective bit length causes a reduction in S / N. The auto-scaling function turns off functions such as the equalizer from the audio data value itself.
The state is read, the gain is amplified by the bit shift operation (while the effective bit is secured), and the gain (set value) of the electronic volume on the analog side is lowered in accordance with the balance to maintain the gain while maintaining the S / N ratio. (See Figs. 2 and 3)

(B) Overflow limiter function The full scale of the signal data (that the signal is at the upper limit / lower limit) is detected, the gain is attenuated by 6 dB (one bit) by the bit shifter, and input to the audio DAC. . Thereafter, the gain is amplified on the electronic volume side in the same procedure as in 1 above, and the original signal is restored. This is effective in preventing signal wave distortion generated at the peak value (see FIG. 4).

(C) Zero-cross function When a zero-cross point for volume switching cannot be detected within the set time, the zero-shift point can be easily set by performing attenuating the gain of the audio data at regular intervals by the zero shifter. Can be produced. A major feature of the present invention is that the system goes to create a zero-cross point on its own. Since the waveform operation is performed by digital data, the LP after the DAC output is output.
With the help of F playing a role in waveform shaping, extremely natural volume value switching can be realized (see FIG. 5).

According to the embodiment of the present invention, the volume control means 4 operated by the user via the microcomputer 2 to control the volume value of the electronic volume main body 1
Audio DCA: 9 in the electronic volume main body 1
Bit shift means 8 comprising a bit shifter (gain adjusting unit) for receiving a digital audio data applied through the digital audio data and performing a bit shift operation for obtaining an effective bit of the digital audio data. A checking means 7 comprising a data value monitor for checking an ON / OFF state of an audio function for performing a gain operation according to a frequency from a bit use state is provided, and audio DSPs: 6, a data value monitor 7, and a bit shift means 8 , Audio DA
C: 9, the electronic volume main body 1, the volume control means 4, and the microcomputer 2 are all integrally integrated as a one-chip integrated circuit, and the audio function confirmed by the confirmation means 7 is turned off.
In the state, when the bit shift means 8 performs the bit shift operation, the compensation control input for compensating for the gain variation due to the bit shift operation of the bit shift means 8 according to the bit shift operation of the bit shift means 8 is changed to the bit shift state. Since the voltage is directly applied from the means 8 to the volume control means 4 without passing through the microcomputer 2,
The control element integrated as a one-chip integrated circuit has an improved S / N performance in which a volume value can be appropriately controlled in accordance with a bit shift operation performed in an OFF state of an audio function such as an equalizer function. An electronic volume with an automatic adjustment function can be obtained.

Further, according to the embodiment of the present invention, the volume control means 4 operated by the user via the microcomputer 2 to control the volume value of the electronic volume main body 1, and the audio DA
C: a bit shift means 8 for inputting audio data applied through 9 and performing a bit shift operation comprising a bit shifter (gain adjusting unit) for obtaining an effective bit of the audio data, wherein a gain corresponding to a frequency is provided. Detecting means for detecting the ON / OFF state of an audio function for performing an operation by the microcomputer 2 based on information of a key switch 3 input by a user, and an audio DSP: 6, a data value monitor 7, a bit shift Means 8, audio DAC: 9, electronic volume main body 1, volume control means 4, and microcomputer 2 are all integrally integrated as an integrated circuit consisting of one chip, and the detection detected by the detection means. When the audio function is OFF, the bit shift means 8 When the shift operation is performed, a compensation control input for compensating for a gain variation due to the bit shift operation of the bit shift means 8 in accordance with the bit shift operation of the bit shift means 8 is transmitted from the bit shift means 8 via the microcomputer 2. Since the voltage is directly applied to the volume control means 4, the audio signal such as the equalizer function detected based on the information of the key switch 3 by the control element integrated as a one-chip integrated circuit is turned off. S / S that can appropriately control the volume value according to the executed bit shift operation
An electronic volume with an automatic adjustment function with improved N performance can be obtained.

Further, according to the embodiment of the present invention, the volume control means 4 operated by the user via the microcomputer 2 to control the volume value of the electronic volume main body 1, and the audio volume main body 1
C: a bit shifter 8 which receives the audio data applied through 9 and performs a bit shift operation comprising a bit shifter (gain adjusting unit) for obtaining an effective bit of the audio data, wherein the audio data value is At full scale, the gain is reduced by the bit shift operation of the bit shift means 8, and the audio DSP: 6, the bit shift means 8, the audio DAC: 9, the electronic volume main body 1, and the volume control means 4, and , Microcomputer 2, all,
The integrated circuit is integrated as a one-chip integrated circuit, and a compensation control input for compensating for a gain change caused by the bit shift operation of the bit shift means 8 in accordance with the bit shift operation of the bit shift means 8 is provided to the bit shift means 8. Is applied directly to the volume control means 4 without going through the microcomputer 2, so that the control element integrated as a one-chip integrated circuit integrally executes the bit executed when the signal data value is at full scale. An electronic volume with an automatic adjustment function with an improved overflow limiter function that can appropriately control the volume value according to the shift operation can be obtained.

[0035]

According to the first aspect of the invention, there is provided a volume control means which is operated by a user via a microcomputer to control a volume value of the electronic volume main body, and wherein the audio data applied to the electronic volume main body is inputted, Bit shift means for performing a bit shift operation of audio data, wherein a compensation control input for compensating for a gain variation due to the bit shift operation of the bit shift means in response to the bit shift operation of the bit shift means is provided from the bit shift means. Since the voltage is applied to the volume control means, an electronic volume with an automatic adjustment function that can appropriately control the volume value according to the bit shift operation can be obtained.

According to the second aspect of the invention, there is provided a volume control means which is operated by a user via a microcomputer to control a volume value of the electronic volume main body, and receives digital audio data applied to the electronic volume main body and receives the digital audio data. Bit shift means for performing a bit shift operation of audio data, a digital signal processor for processing digital audio data input to the bit shift means, and an electronic volume which converts an output of the bit shift means into an analog signal. A D / A converter for applying to the main body, wherein the digital signal processor, bit shift means, D / A
The converter and the volume control means are integrally integrated as an integrated circuit, and a compensation control input for compensating for a gain variation due to the bit shift operation of the bit shift means in accordance with the bit shift operation of the bit shift means is provided to the bit shift means. Since the voltage is applied to the volume control means, it is possible to obtain an electronic volume with an automatic adjustment function capable of appropriately controlling the volume value according to the bit shift operation by the control element integrated integrally.

According to the third aspect of the present invention, the volume control means which is operated by the user via the microcomputer to control the volume value of the electronic volume main body, and receives the audio data applied to the electronic volume main body and receives the audio data. Bit shift means for performing a bit shift operation for gaining effective bits, and a compensation control input for compensating for a gain change due to the bit shift operation of the bit shift means in accordance with an increase in gain due to the bit shift operation of the bit shift means. Since the voltage is applied from the bit shift means to the volume control means, it is possible to obtain an electronic volume with an automatic adjustment function capable of appropriately controlling a volume value in accordance with a bit shift operation for obtaining valid bits of audio data. .

According to the fourth aspect of the present invention, there is provided a volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and audio data applied to the electronic volume main body being inputted and receiving the audio data. Bit shifting means for performing a bit shifting operation of the audio data, and checking means for checking an ON / OFF state of an audio function for performing a gain operation according to a frequency from a use state of upper bits in the audio data, Compensation control for compensating for a gain variation due to the bit shift operation of the bit shift means according to the bit shift operation of the bit shift means when the bit shift means performs the bit shift operation in the OFF state of the audio function confirmed by Bit shift the input Since the voltage is applied to the volume control means from the stage, the volume value can be appropriately controlled in accordance with the bit shift operation performed in the OFF state of the audio function such as the equalizer function. The improved automatic adjustment of the S / N performance. An electronic volume with function can be obtained.

According to the fifth invention, a volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and audio data applied to the electronic volume main body being input and receiving the audio data And a detecting means for detecting the ON / OFF state of an audio function for performing a gain operation in accordance with a frequency by the microcomputer based on key switch information input by a user. In addition, when the bit shift means performs the bit shift operation in the OFF state of the audio function detected by the detection means, the gain by the bit shift operation of the bit shift means according to the bit shift operation of the bit shift means. Compensation control input to compensate for fluctuation Is applied from the bit shift means to the volume control means, so that the volume value is appropriately adjusted in accordance with a bit shift operation performed in an OFF state of an audio function such as an equalizer function detected based on key switch information. Controllable S / N
An electronic volume with an automatic adjustment function with improved performance can be obtained.

According to the sixth aspect of the invention, there is provided a volume control means which is operated by a user via a microcomputer to control a volume value of the electronic volume main body, and wherein the audio data applied to the electronic volume main body is inputted and the audio data is inputted. Bit shifting means for performing a bit shifting operation of (a) .When the audio data value is at full scale, the gain is reduced by the bit shifting operation of the bit shifting means, and in accordance with the bit shifting operation of the bit shifting means. Since the compensation control input for compensating for the gain variation due to the bit shift operation of the bit shift means is applied from the bit shift means to the volume control means, the bit shift operation executed when the signal data value is at full scale. Volume value according to It is possible to obtain an improved electronic volume with automatic adjustment function of the overflow limiter function that can be controlled.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an electronic volume according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the necessity of auto scaling.

FIG. 3 is an explanatory diagram showing a configuration relating to auto scaling in an embodiment according to the present invention.

FIG. 4 is an explanatory diagram showing an overflow limiter according to an embodiment of the present invention in comparison with a conventional technique.

FIG. 5 is an explanatory diagram showing a volume switching operation at the time of zero crossing in an embodiment according to the present invention, in comparison with a conventional technology.

FIG. 6 is a block diagram showing an overall configuration of an electronic volume according to the related art.

[Explanation of symbols]

1. Electronic volume main unit, 2 microcomputer, 3 key switch, 4 volume control means, 5 digital data input terminal, 6 audio DSP, 7 data value monitor confirmation means, 8 bit shifter (gain adjustment unit) bit shift means, 9 Audio DA
C, 10 Audio data output terminal.

Claims (6)

[Claims] 1. A volume control means operated by a user via a microcomputer to control a volume value of an electronic volume main body, and receives audio data applied to the electronic volume main body and performs a bit shift operation of the audio data. A bit shift unit, wherein a compensation control input for compensating for a gain variation caused by the bit shift operation of the bit shift unit in response to the bit shift operation of the bit shift unit is applied from the bit shift unit to the volume control unit. Electronic volume with automatic adjustment function. 2. A volume control means operated by a user via a microcomputer to control a volume value of an electronic volume main unit, and a digital audio data bit shift operation which receives digital audio data applied to the electronic volume main unit. , A digital signal processor for processing digital audio data input to the bit shift means, and a digital signal processor for converting the output of the bit shift means into an analog signal and applying the analog signal to the electronic volume main body. A
A digital signal processor, a bit shift means, a D / A converter, and a volume control means are integrally integrated as an integrated circuit, and the bit shift is performed in accordance with a bit shift operation of the bit shift means. An electronic volume with an automatic adjustment function, wherein a compensation control input for compensating for a gain variation due to a bit shift operation of the means is applied from the bit shift means to the volume control means. 3. A volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and for inputting audio data to be applied to the electronic volume main body and earning valid bits of the audio data. A bit shift means for performing a bit shift operation, wherein a compensation control input for compensating for a gain change caused by the bit shift operation of the bit shift means in accordance with a gain increase by the bit shift operation of the bit shift means is provided from the bit shift means. The electronic volume with an automatic adjustment function according to claim 1 or 2, wherein the electronic volume is applied to a volume control means. 4. A volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and receives audio data applied to the electronic volume main body and performs a bit shift operation of the audio data. An audio function for performing a gain operation in accordance with a frequency from a use state of upper bits in the audio data.
A confirmation means for confirming the FF state is provided, and when the bit shift means performs the bit shift operation in the audio function OFF state confirmed by the confirmation means, the bit is transmitted in accordance with the bit shift operation of the bit shift means. 3. The automatic adjustment function according to claim 1, wherein a compensation control input for compensating for a gain change caused by a bit shift operation of the shift means is applied from the bit shift means to the volume control means. Electronic volume. 5. A volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and receives audio data applied to the electronic volume main body and performs a bit shift operation of the audio data. ON / OF of an audio function including a bit shift means and performing a gain operation according to a frequency
A detection means for detecting the F state by the microcomputer based on key switch information input by a user is provided, and the bit shift means performs a bit shift operation in an OFF state of the audio function detected by the detection means. Wherein, when the bit shift means performs a bit shift operation, a compensation control input for compensating for a gain variation due to the bit shift operation of the bit shift means is applied from the bit shift means to the volume control means. The electronic volume with an automatic adjustment function according to claim 1 or 2. 6. A volume control means operated by a user via a microcomputer to control a volume value of the electronic volume main body, and receives audio data applied to the electronic volume main body and performs a bit shift operation of the audio data. Bit shifting means, wherein when the audio data value is at full scale, the gain is reduced by the bit shifting operation of the bit shifting means, and the bit of the bit shifting means is changed according to the bit shifting operation of the bit shifting means. 3. The electronic volume with an automatic adjustment function according to claim 1, wherein a compensation control input for compensating for a gain change due to a shift operation is applied from the bit shift means to the volume control means.