JP3329758B2 - SS radio receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum radio receiving apparatus (hereinafter, referred to as "SS radio receiving apparatus" in the present specification) using a direct spread system, and in particular, to a demodulated signal. The present invention relates to an SS radio receiving apparatus having a function of automatically adjusting the amplitude level of a baseband signal.

[0002]

2. Description of the Related Art In general, when performing reception in an SS radio receiving apparatus using a direct spreading method, a high-frequency modulated signal output from a transmitting apparatus is taken in via an antenna, and this harmonic modulated signal is demodulated. The data is reproduced in the receiving device based on the data thus obtained.

In a conventional SS radio receiving apparatus, as shown in a block diagram of FIG. 6, a high-frequency modulated signal SA1 output from a transmitting apparatus is input via an antenna, and a high-frequency modulated signal SA1 is amplified with low noise. Amplified high frequency modulation signal S
A2, a low-noise amplifier 1, a high-frequency modulation signal SA2 output from the low-noise amplifier 1 is input, converted to an intermediate frequency, and outputs an IF modulation signal SA3. A filter 3 that receives an IF modulated signal SA3 and removes unnecessary components and outputs an IF modulated signal SA4, and a demodulator 4 that receives the IF modulated signal SA4 output from the filter 3 and converts it into a baseband signal SA5. When,
An A / D converter 5 for converting a baseband signal SA5 output from the demodulator 4 into a digital signal SD1, and a digital signal SD1 output from the A / D converter are input to the original digital data SD2. Control circuit 6 for demodulation
And

Next, the operation of this conventional SS radio receiving apparatus will be described. In this SS radio receiving apparatus, the high-frequency modulated signal SA1 output from the transmitting apparatus is input to the low-noise amplifier 1 and amplified with low noise. The amplified high-frequency modulated signal SA2 is input to the down-converter 2 and frequency-converted to an IF modulated signal SA3 that is an intermediate frequency. The IF modulated signal SA3 output from the down converter 2 is input to the filter 3, and the filter 3
IF modulation signal S obtained by removing unnecessary components from modulation signal SA3
A4 is output.

[0005] The IF modulated signal SA4 is input to the demodulator 4 and frequency-converted to a baseband signal SA5. The converted baseband signal SA5 is input to the A / D converter 5, and is converted into a digital signal SD1. The converted digital signal SD1 is converted by the control circuit 6 into the original digital data SD2.

[0006]

However, in the above-described conventional SS radio receiving apparatus, since the baseband signal output from the demodulator is an analog signal, the amplitude level may be different between the positive polarity and the negative polarity. In this case, a problem occurs in which the receiving device reproduces data different from the data transmitted by the transmitting device.

Therefore, there is a problem that the amplitude level of the baseband signal must be adjusted so as to be constant between the positive polarity and the negative polarity. In addition, the above-mentioned problem becomes a problem particularly when a modulation method for providing data in the amplitude direction of the baseband signal is used.

The present invention solves such a problem of the prior art. Even when the amplitude level of a baseband signal output from a demodulator differs between positive polarity and negative polarity, the amplitude level is changed to positive polarity and negative polarity. It is an object of the present invention to provide an SS radio receiving apparatus capable of automatically adjusting and correcting so as to be constant in nature.

[0009]

[0010]

Means for Solving the Problems The invention of claim 1 is a direct
In the SS radio receiver using the spread method, the demodulator
The amplitude level of the converted baseband signal
A detecting unit for adjusting an amplitude level of the baseband signal;
An adjustment unit, and the baseband detected by the detection unit.
Control for controlling the adjustment unit based on a signal amplitude level
And a section, wherein the detection unit, the base band signal and the threshold voltage is input, and formed by these comparators to the result of comparing the two values and outputs a low signal or a high signal, the controller after setting the threshold voltage input to the comparator reference voltage, and observing the output of the comparator while changing the threshold voltage, the high level of the output signal of the comparator b
The threshold voltage when the level times are equal
Controlling the adjusting unit based on a difference between the control voltage and the reference voltage.
The present invention relates to an S wireless receiving device. According to the SS radio receiving apparatus having the above configuration, the detection unit outputs the baseband output from the demodulator.
The signal level is detected, and the control unit detects the signal level.
Control unit based on the amplitude level of the baseband signal
Control unit optimizes the amplitude level of the baseband signal.
adjust. In addition, the detector is used as a baseband signal and a threshold.
Value voltage is input, and the result of comparing these two values is
The comparator that outputs a low signal or high signal
And the control unit is input to the comparator.
After setting the threshold voltage to the reference voltage,
Observe the output of the comparator while changing the voltage
The high and low levels of the output signal of the comparator
The above threshold voltage when the bell times are equal
The adjustment unit can be controlled based on the difference from the reference voltage .

[0011]

[0012]

[0013]

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 3 of the present invention will be specifically described with reference to FIGS. In the description of the first to third embodiments, the same components and components as those of the conventional example shown in FIG. Example 1
As shown in FIG. 1 to FIG.
A high-frequency modulation signal SA1 output from the transmitting device is input via an antenna, a low-noise amplifier 1 that amplifies the high-frequency modulation signal SA1 with low noise, and outputs an amplified high-frequency modulation signal SA2, and an output from the low-noise amplifier 1. The high-frequency modulation signal SA2 is input, the down-converter 2 converts the signal into an intermediate frequency and outputs an IF modulation signal SA3, and the IF modulation signal SA3 output from the down-converter 2 is input to remove unnecessary components and perform IF modulation. A filter 3 for outputting a signal SA4, a demodulator 4 to which an IF modulated signal SA4 output from the filter 3 is input and converting it to a baseband signal SA5, and a baseband signal SA5 output from the demodulator 4 Signal SD1
And a control circuit 6 to which the digital signal SD1 output from the A / D converter 5 is input and demodulated to the original digital data SD2.

(Embodiment 1) In the SS radio receiving apparatus of Embodiment 1, as shown in the block diagram of FIG.
Amplifier 10 that receives baseband signal SA5 and outputs baseband signal SA6 between
And a CPU 7, a comparator 8, a D / A
It has converters 9 and 11. Then, the CPU 7 outputs a control signal CL1, and the D / A converter 9 outputs a predetermined threshold voltage SV1 specified by the control signal CL1 from the CPU 7.
And supplies it to the comparator 8 as the threshold voltage SV1. The baseband signal SA5 is input to the comparator 8 together with the threshold voltage SV1, and a low signal or a high signal is output as an output signal LH as a result of comparing the input binary values, and is input to the CPU 7.

Next, the CPU 7 calculates a control signal CL2 based on the comparison result of the comparator 8, and inputs the control signal CL2 to the D / A converter 11. Then, the D / A converter 11 outputs the CP
The bias voltage SV2 specified by the control signal CL2 from U7 is generated, and the amplification of the amplifier 10 is automatically adjusted by the bias voltage SV2 output from the D / A converter 11, so that the baseband signal SA6 at the optimum level is obtained. Can be obtained.

(Embodiment 2) The SS radio receiving apparatus of Embodiment 2 does not have the amplifier 10 like the SS radio receiving apparatus of Embodiment 1, but detects the level of the baseband signal SA5, and Is the same as that of the first embodiment until the control signal CL3 is output. As shown in the block diagram of FIG. 2, the D / A converter 12 generates a reference voltage SV3 specified by a control signal CL3 from the CPU 7,
The signal is output as the reference voltage SV3 of the A / D converter 5. In the A / D converter 5 to which the baseband signal SA5 is input,
By adjusting the reference voltage SV3, the difference between the positive polarity and the negative polarity of the amplitude level of the baseband signal SA5 detected by the comparator 8 is adjusted and corrected.

(Embodiment 3) In the SS radio receiving apparatus of Embodiment 3, as shown in the block diagram of FIG.
And an A / D converter 5, an amplifier 10, a CPU 7, and a D / A converter 13. The baseband signal SA6 adjusted by the amplifier 10 is input to the D / A converter 13, and the CPU 7 generates the control signal CL4 while observing the most significant output data of the A / D converter 5,
It is supplied to the D / A converter 13. The D / A converter 13 generates a bias voltage SV4 specified by the control signal CL4, and the amplification degree of the amplifier 10 is controlled by the bias voltage SV4, so that an optimal level of the baseband signal SA6 can be obtained.

In the SS radio receiving apparatuses according to the first to third embodiments, the low noise amplifier 1 is used to amplify the high frequency modulation signal with low noise. Down converter 2
It is used to convert the high-frequency modulation signal to an intermediate frequency, and receives an IF modulation signal SA3. Filter 3
Is used to remove image frequency generated by the down converter 2 and unnecessary components generated at a frequency other than the required IF modulation signal SA3. The demodulator 4 has an IF
It is used to convert modulated signal SA3 to baseband signal SA5. The A / D converter 5 is used to convert the baseband signal SA5 to a digital signal SD1. The control circuit 6 is used for demodulating the input digital signal SD1 to the original digital signal SD2.

Next, a processing procedure for automatically adjusting the amplitude level of the baseband signal will be described below. Figure 1
As shown in FIGS. 2 and 4, when performing automatic adjustment of the amplitude level of the baseband signal SA5, first, the reference voltage of the amplitude level is set to, for example, 0 V (step S).
1). Next, the CPU 7 generates a control signal CL1 and outputs D /
The A converter 9 is controlled to generate a predetermined threshold voltage SV1, and the threshold voltage SV1 is supplied to the comparator 8.
The threshold voltage SV1 and the baseband signal SA5 are input to the comparator 8. From the comparator 8,
A low signal or a high signal is output as an output signal LH as a result of comparing the input binary values, and is input to the CPU 7.

The output signal LH is observed by the CPU 7, the signal level of the threshold voltage SV1 of the comparator 8 is sequentially changed (step S2), and the high level and the low level of the output signal LH are equalized until the time becomes equal. The process is repeated (Step S3). Based on the threshold voltage SV1 when the time of the high level becomes equal to the time of the low level at the output of the comparator 8, the CPU 7 performs a predetermined operation to complete the detection of the difference between the positive and negative amplitude levels (step S4). ), And store the threshold voltage SV1 (step S5).

Next, the comparator 8 compares the stored threshold voltage SV1 with the reference voltage (step S5).
6). In the SS radio receiving apparatus according to the first embodiment, when the threshold voltage and the reference voltage are the same, the current value of the bias voltage of the amplifier 10 is held (step S7). On the other hand, if the threshold voltage is different from the reference voltage, the CPU 7 calculates and calculates an optimum bias voltage based on the difference between the threshold voltage and the reference voltage (step S8). next,
The D / A converter 11 is controlled so that the optimum bias voltage calculated by the CPU 7 is obtained, and the bias voltage is supplied to the amplifier 10 (see FIG. 1).

In the SS radio receiving apparatus according to the second embodiment,
When the threshold voltage SV1 is equal to the reference voltage,
The current value of the reference voltage of the A / D converter 5 is held (Step S7). On the other hand, when the threshold voltage SV1 is different from the reference voltage, the CPU 7 calculates the optimum reference voltage of the A / D converter 5 based on the difference between the threshold voltage SV1 and the reference voltage (step S8). . Next, the D / A converter 12 is controlled so that the optimum reference voltage calculated by the CPU 7 is obtained, and the reference voltage is supplied to the A / D converter 5 (see FIG. 2). As a result, the amplitude level of the baseband signal is adjusted so that there is no difference between the positive and negative amplitude levels, so that the adjustment of the amplitude level of the baseband signal is completed (step S
9).

As shown in FIGS. 3 and 5, in the SS radio receiving apparatus of the third embodiment, the baseband signal SA
When performing the automatic adjustment of the amplitude level of the amplifier 5, the amplifier 1
A reference voltage of zero bias voltage SV4 is set (step S11). Next, the CPU 7 generates a control signal CL4 to control the D / A converter 13, and the predetermined bias voltage SV4
Is generated, and the bias voltage SV4 is supplied to the amplifier 10. The bias voltage SV4 and the baseband signal SA5
Are input to the amplifier 10. The amplifier 10 outputs a baseband signal SA6 whose amplitude level has been adjusted based on the input bias voltage SV4.

The CPU 7 observes the highest-order output data SD3 of the A / D converter 5, and detects the bias voltage SV of the amplifier 10.
4 (step S12), and A /
This process is repeated until a high signal is output as the most significant output data SD3 of the D converter 5 (step S13).
When a high signal is output to the output data SD3, the automatic adjustment of the amplitude level ends (step S14), and the amplifier 1
The bias voltage SV4 of 0 is stored (step S1).
5).

As described above, by performing this automatic adjustment, the amplitude level of the baseband signal
Even if the polarity differs, the amplitude level of the baseband signal can be corrected to the optimum value, so that the data transmitted by the transmitting device can always be correctly reproduced,
It is possible to improve the demodulation accuracy.

[0027]

[0028]

According to SS radio receiver of the present invention, recovery
The amplitude level of the baseband signal output from the
Output from demodulator even if polarity and negative polarity are not constant
Detects the amplitude level of the baseband signal and the detection result
Adjusts the adjustment unit based on the amplitude of the baseband signal.
The bell can be optimally corrected. In addition, the detection unit,
A baseband signal and a threshold voltage are input, and the result of comparing these two values is formed by a comparator that outputs a low signal or a high signal output signal, and the threshold voltage input to the comparator is changed. While before
Observe the output of the comparator
The time of the high level and the low level of the output signal become equal.
Based on the difference between the threshold voltage when the
The adjusting unit can be controlled.

[0029]

[0030]

[0031]

[Brief description of the drawings]

FIG. 1 is a block diagram of an SS wireless receiving apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an SS radio receiving apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram of an SS radio receiving apparatus according to a third embodiment of the present invention.

FIG. 4 is a flowchart of a processing procedure for automatically adjusting the amplitude level of a baseband signal according to the first and second embodiments of the present invention.

FIG. 5 is a flowchart of a processing procedure for automatically adjusting the amplitude level of a baseband signal according to a third embodiment of the present invention.

FIG. 6 is a block diagram of a conventional SS radio receiving apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Low noise amplifier, 2 ... Down converter, 3 ... Filter, 4 ... Demodulator, 5 ... A / D converter, 6 ... Control circuit, 7 ... CPU, 8 ... Comparator, 9,11,12,
13 ... D / A converter, 10 ... Amplifier.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04B 1/69-1/713 H04J 13/00-13/06

Claims (1)

(57) [Claims] 1. An SS radio receiving apparatus using a direct spreading system, comprising: a detecting section for detecting an amplitude level of a baseband signal converted by a demodulator; and an adjusting section for adjusting the amplitude level of the baseband signal. A control unit that controls the adjustment unit based on the amplitude level of the baseband signal detected by the detection unit, wherein the detection unit includes the base unit.
The band signal and the threshold voltage are input, and these 2
Outputs a low signal or high signal for the result of the value comparison.
The control unit is formed by a comparator
Set threshold voltage input to comparator to reference voltage
Then, while changing the threshold voltage, the
Observing the output of the comparator, the output signal of the comparator
When the high level and low level time of
The adjustment is performed based on a difference between the threshold voltage and the reference voltage.
An SS radio receiving apparatus for controlling an adjusting section .