JP2002374134A - Analog signal conversion circuit and communication equipment using the circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analog signal conversion circuit, which enables desired signal conversion processing using a comparatively simple configuration, without decreasing or deteriorating the precision of an analog signal. SOLUTION: In the analog signal conversion circuit 20, a DC voltage (detection voltage Vs) which is determined based on an input signal X(t) is detected from the signal X(t) inputted in an input terminal 21, by a waveform preprocessing part 24. An arbitrary function F(x), which generates the voltage Vs and a reference voltage Vrf from a reference voltage source 22 parameters, is operated by a function-computing element 26, and an operation result Z is outputted. A multiplier 28 multipliers the operation result Z and the input signal X(t) together, and outputs an output signal Y(t). The arbitrary function operation F(x) is performed, and the input signal X(t) is multiplied by the operation result Z, so that the desired signal conversion processing is enabled with a comparative simple configuration, without decreasing or deteriorating precision of the input signal X(t).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an analog signal conversion circuit that performs an arbitrary function operation on an input analog signal and outputs the result, and a communication device using the same.

[0002]

2. Description of the Related Art With the spread of digital circuits in recent years, processing for performing an arbitrary function operation on an input analog signal and outputting the result, for example, amplitude conversion processing, signal level adjustment processing, filtering processing, etc., has been largely performed in circuit design. Due to the simplicity and the high degree of freedom of the setting parameters, there is a fact that more cases are realized using digital circuits than analog circuits.

For example, in a circuit for performing an amplitude conversion process, an input analog signal is converted into a digital signal by an A / D conversion circuit, and then a predetermined operation is performed by a digital circuit to convert the signal into an output signal having a desired amplitude. It is configured to

In a circuit for performing a signal level adjustment process, similarly, an analog input signal is converted into a digital signal by an A / D conversion circuit, and a predetermined operation is performed by the digital circuit to output a signal having a desired signal level. It is configured to convert to a signal.

[0005]

However, the arithmetic processing by the digital circuit is inevitably a discrete value arithmetic processing, so that there is a problem that the accuracy is reduced with a minute value close to zero. That is, due to the essential characteristics of digital processing, continuous values cannot be continuously processed. Therefore, no matter how much the sampling width is reduced, it is not possible to prevent information loss in an area near zero as much as possible. There's a problem.

In a circuit for performing signal level adjustment processing, predetermined arithmetic processing is performed uniformly unless the input analog signal is completely zero. Therefore, when the analog input signal has a value close to zero (for example, zero). (A very small noise signal, etc.) which is close to the above, has a problem that an arithmetic processing with an extremely high gain is performed and the output signal waveform is deteriorated.

Further, in a communication apparatus employing a configuration in which an analog signal is processed by such a digital circuit, problems in signal conversion processing by the digital circuit include, for example, deterioration of transmission / reception signals and reduction of S / N. Therefore, there is a problem that the presence of the digital circuit greatly affects the performance of the communication device itself.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to achieve a desired structure by a relatively simple configuration without deteriorating and deteriorating the accuracy of analog signals. An object of the present invention is to provide an analog signal conversion circuit capable of performing a signal conversion process. Another object of the present invention is to provide a communication device capable of suppressing deterioration of a transmission / reception signal and reduction of S / N.

[0009]

Means for Solving the Problems and Actions and Effects of the Invention
In order to achieve the above object, the analog signal conversion circuit according to claim 1 is an analog signal conversion circuit that performs an arbitrary function operation on an input analog signal and outputs the result, wherein a DC voltage source that generates a predetermined DC voltage And, a DC voltage detector for detecting a DC voltage determined based on the input analog signal, and a predetermined DC voltage generated by the DC voltage source and a detection voltage detected by the DC voltage detector, A function operation unit that calculates an arbitrary function using both parameters as parameters and outputs the operation result, and inputs the operation result and the analog signal by the function operation unit, multiplies both, and outputs an output signal A multiplier to
Is a technical feature.

According to the first aspect of the present invention, a DC voltage source generates a predetermined DC voltage, a DC voltage detector detects a DC voltage determined based on an analog signal input, and a function calculator calculates the DC voltage. An arbitrary function using the predetermined DC voltage generated by the source and the detection voltage detected by the DC voltage detector as a parameter is output, and this calculation result is output. The calculation result by the function calculator and the analog signal are output by the multiplier. Multiply and output an output signal. That is, the input analog signal is a DC voltage detector that detects a DC voltage determined based on the analog signal, and functions as an arbitrary function using the detected voltage and a predetermined DC voltage from a DC voltage source as parameters. The calculation is performed by the calculator and the calculation result is output. Then, a multiplier multiplies the operation result by the input analog signal and outputs the result as an output signal. Thereby, an arbitrary function operation is performed by using the detection voltage determined based on the input analog signal and a predetermined DC voltage as parameters, and the calculation result is multiplied by the input analog signal. With a relatively simple configuration including a DC voltage detector, a function calculator, and a multiplier, an input analog signal can be subjected to any function calculation and output. Therefore, there is an effect that a desired signal conversion process can be performed with a relatively simple configuration without lowering the accuracy and deterioration of the analog signal.

Further, in the analog signal conversion circuit according to the present invention, the analog signal input to the multiplier is different from the analog signal input to the DC voltage detector. It is a technical feature that the signal is an analog signal.

According to the second aspect of the present invention, the analog signal input to the multiplier is another analog signal different from the analog signal input to the DC voltage detector. The calculation result output by the calculation by the function calculator is multiplied by the other analog signal. Thereby, an arbitrary function operation is performed with the detection voltage determined based on the input analog signal and a predetermined DC voltage as parameters, and the calculation result is multiplied by the other input analog signal. The other input analog signal can be signal-converted based on the signal information of the input analog signal. Therefore, a desired signal conversion process can be performed on such other input analog signals with a relatively simple configuration without causing a decrease in accuracy and deterioration of the other input analog signals. There is an effect to get.

Further, in the analog signal conversion circuit according to claim 3, in claim 1 or 2, the arbitrary function is:
A technical feature is that a predetermined DC voltage generated by the DC voltage source is divided by a detection voltage detected by the DC voltage detector.

According to the third aspect of the present invention, the arbitrary function is to divide a predetermined DC voltage generated by the DC voltage source by a detection voltage detected by the DC voltage detector, so that the input analog It is possible to obtain a ratio of a predetermined DC voltage by the DC voltage source to a DC voltage determined based on the signal. Thereby, when the detection voltage is higher than the predetermined DC voltage, 0
When the value of <Z <1 is obtained and the detected voltage is smaller than the predetermined DC voltage, the value of Z> 1 is obtained as the division result Z. Therefore, when the division result Z as the operation result and the input analog signal are multiplied by the multiplier, an output of a predetermined DC voltage or less can be obtained as an output signal. That is, even if the level of the input signal fluctuates, the input signal can be converted so as to output an output signal of the predetermined DC voltage or less without forming a feedback loop. Therefore, with a relatively simple configuration, there is an effect that a signal conversion process of converting an input signal so as to output an output signal of a predetermined DC voltage or less can be performed without causing a decrease in accuracy and deterioration of an analog signal.

According to a fourth aspect of the present invention, there is provided a communication apparatus using the analog signal conversion circuit according to the first aspect, wherein the analog signal is an extracted signal extracted from a baseband signal. And the arbitrary function is a predetermined DC voltage generated by the DC voltage source,
By the detection voltage detected by the DC voltage detector,
It is a technical feature that the division is performed.

According to the fourth aspect of the present invention, the input analog signal is an extracted signal extracted from the baseband signal, and an arbitrary function by the function calculator is to convert a predetermined DC voltage generated by a DC voltage source into a DC voltage. Since the signal is divided by the detection voltage detected by the detector, the extracted signal extracted from the baseband signal is detected by a DC voltage detector at a DC voltage determined based on the extracted signal. An arbitrary function using a predetermined DC voltage from a voltage source as a parameter is calculated by a function calculator, and this calculation result is output. Then, the calculation result and the extracted signal are multiplied by a multiplier and output as an output signal. Thereby, an arbitrary function operation using the detection voltage determined based on the extraction signal and a predetermined DC voltage as parameters is performed, and the operation result is multiplied by the extraction signal, so that the DC voltage source, the DC voltage detector , The extracted signal can be subjected to any function operation and output with a relatively simple configuration of a function operation unit and a multiplier. Therefore, with a relatively simple configuration, there is an effect that a desired signal conversion process can be performed without causing a decrease in accuracy and deterioration of an extracted signal extracted from a baseband signal. There is an effect that the reduction of N can be suppressed.

Further, in the communication device according to the fifth aspect, the second aspect
A communication device using the analog signal conversion circuit according to claim 1, wherein the analog signal is an extracted signal extracted from a baseband signal, the other input analog signal is the baseband signal, Function is
A technical feature is that a predetermined DC voltage generated by the DC voltage source is divided by a detection voltage detected by the DC voltage detector.

According to the fifth aspect of the invention, the input analog signal is an extracted signal extracted from the baseband signal, the other input analog signal is the baseband signal, and the arbitrary function is a DC voltage. Since the predetermined DC voltage generated by the source is divided by the detection voltage detected by the DC voltage detector, the extracted signal extracted from the baseband signal is determined by the DC voltage detector based on the extracted signal. A DC voltage is detected, an arbitrary function using the detected voltage and a predetermined DC voltage from a DC voltage source as parameters is calculated by a function calculator, and the calculation result is output. Then, the calculation result and the baseband signal are multiplied by a multiplier and output as an output signal. Thereby, an arbitrary function operation is performed by using the detection voltage determined based on the extraction signal extracted from the baseband signal and a predetermined DC voltage as parameters, and the operation result is multiplied by the baseband signal. The baseband signal can be converted based on the signal information. Therefore, even for such a baseband signal, a relatively simple configuration has an effect of performing a desired signal conversion process without causing a decrease in accuracy and deterioration of the baseband signal. This has the effect of suppressing signal degradation and S / N degradation.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an analog signal conversion circuit and a communication apparatus using the same according to the present invention.

[First Embodiment] First, the configuration of an analog signal conversion circuit according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of the analog signal conversion circuit 20 according to the first embodiment.

As shown in FIG. 1, the analog signal conversion circuit 20 mainly includes a reference voltage source 22, a waveform pre-processing unit 24, a function calculator 26, and a multiplier 28. Analog signal (hereinafter referred to as “input signal X
(t) ". ) Is subjected to an arbitrary function operation and output terminal 2
9 is output as an output signal Y (t).

The reference voltage source 22 is a DC voltage source that generates a reference voltage Vrf as a predetermined DC voltage. The reference voltage source 22 is configured to generate an arbitrary DC constant voltage by changing its setting, and the reference voltage Vrf generated by the reference voltage source 22 is output by a function calculator 26 described later. Is a parameter for the function operation of.

The waveform preprocessing section 24 detects a DC voltage (detection voltage Xs) determined based on the input signal X (t) input to the input terminal 21. Here, "DC voltage (detection voltage X) determined based on input signal X (t)"
s) "refers to a constant DC voltage obtained in relation to a varying input level of the input signal X (t), for example,
The absolute maximum value (> 0), average value, absolute value, etc. of the input signal X (t) within a predetermined period (for example, one cycle). This detection voltage Xs is also a parameter for an arbitrary function operation by the function operation unit 26.

The function calculator 26 receives the reference voltage Vrf generated by the reference voltage source 22 and the detection voltage Xs detected by the waveform preprocessor 24, and calculates an arbitrary function F (x) using both of them as parameters. Thus, the operation result Z is output. That is, an arbitrary function operation F (x) is performed using the above-described reference voltage Vrf and the detection voltage Xs as parameters to obtain an operation result Z. Here, the “arbitrary function F (x)” means multiplication, division, addition, and subtraction of the reference voltage Vrf and the detection voltage Xs, or the square, square root, differentiation, integration, and phase of the reference voltage Vrf or the detection voltage Xs itself. The calculation result Z is obtained by shift, time delay, level shift, and the like.

The multiplier 28 receives the operation result Z by the function operation unit 26 and the input signal X (t), multiplies the two, and outputs an output signal Y (t). That is, by multiplying the input signal X (t) by the operation result Z by the function operation unit 26, an arbitrary function operation F (x) is added to the input signal X (t).
And outputs an output signal Y (t) to the output terminal 29.

By configuring the analog signal conversion circuit 20 in this manner, the input signal X (t) input to the input terminal 21 is a DC signal determined by the waveform preprocessing unit 24 based on the input signal X (t). A voltage (detection voltage Xs) is detected, and an arbitrary function F (x) using the detection voltage Xs and the reference voltage Vrf from the reference voltage source 22 as parameters is calculated by the function calculator 26, and the calculation result Z is output. I do. The operation result Z and the input signal X (t) are output from the multiplier 28.
And output as an output signal Y (t).

Thus, an arbitrary function operation F (x) using the detection voltage Xs determined based on the input signal X (t) and the reference voltage Vrf as parameters is performed, and the operation result Z is input to the input signal X (t). ), The input signal X (t) is subjected to an arbitrary function operation F (x) by a relatively simple configuration of the reference voltage source 22, the waveform preprocessor 24, the function operation unit 26, and the multiplier 28. Can be output. Therefore, with a relatively simple configuration, the accuracy of the input signal X (t) (analog signal) is not degraded and deteriorated.
There is an effect that desired signal conversion processing can be performed.

The reference voltage source 22 and the waveform preprocessing unit 2
4. Since each of the function calculator 26 and the multiplier 28 can be configured by an operational amplifier or the like, they can be configured by a hybrid IC (hybrid integrated circuit) or the like without using discrete components. Therefore, a further simple configuration can be realized.

Next, the above-described analog signal conversion circuit 20
Is applied to the signal level adjusting circuit 30 and the operation will be described with reference to FIGS. FIG. 2 is a block diagram showing the configuration of the signal level adjustment circuit 30.
FIG. 3 is an explanatory diagram showing an example of the waveform of a signal processed by the signal level adjustment circuit 30, and FIGS.
Input signal X processed by the signal level adjustment circuit 30
(t) peak voltage Xpk and output signal Y (t) peak voltage Y
Input / output characteristic diagrams showing the relationship with pk are shown.

As shown in FIG. 2, the signal level adjusting circuit 3
0 has substantially the same configuration as that of the above-described analog signal conversion circuit 20, and includes a waveform preprocessing unit 34 and a function operation unit 3
6 is different from the analog signal conversion circuit 20 in that the processing content of No. 6 is more specifically specified. Therefore, the same reference numerals are given to components substantially the same as the configuration of the analog signal conversion circuit 20, and description thereof will be omitted.

The waveform pre-processing unit 34, like the above-described waveform pre-processing unit 24, outputs the input signal X input to the input terminal 21.
(t) is detected. Here, as shown in FIG. 3A, the absolute maximum value of the input signal X (t) within a predetermined period (for example, one cycle) is detected as shown in FIG. >
0), that is, a peak voltage X having an amplitude as shown in FIG.
It is configured to detect pk.

The function calculator 36 also performs an arbitrary function calculation F (x) using the reference voltage Vrf and the detection voltage Xs as parameters to obtain a calculation result Z, similarly to the function calculator 26 described above. However, here, any function F (x)
Is divided by both parameters (the reference voltage Vrf and the peak voltage Xpk). That is, an arbitrary function F
(x) is set in the following equation (1).

F (x) = Vrf / Xpk (1)

From the equation (1), the ratio of the reference voltage Vrf to the peak voltage Xpk of the input signal X (t) can be obtained. Specifically, first, as shown in FIG. 3C, the reciprocal (1 / Xpk) of the peak voltage Xpk is calculated, and the calculation result is multiplied by the reference voltage Vrf (Vrf / Xpk) to obtain the result shown in FIG. And the calculation result Z as shown in the following equation (2) is obtained.

Z = Vrf / Xpk (2)

Thus, the peak voltage Xpk becomes equal to the reference voltage Vpk.
When it is larger than rf, the operation result Z is 0 <Z <1.
Can be obtained, and when the peak voltage Xpk is smaller than the reference voltage Vrf, Z> 1
Can be obtained. Since both the peak voltage Xpk and the reference voltage Vrf are positive DC voltage values,
The calculation result Z is a positive DC voltage value.

When the operation result Z is multiplied by the input signal X (t) by the multiplier 28 at the subsequent stage, an output signal Y (t) can be obtained by the following equation (3).

Y (t) = Z × X (t) (3)

Here, the above equation (3) is replaced by the following equation (4):
(5), and the input signal X
(t) divided by peak voltage Xpk (X (t) / Xpk)
Can be expressed as shown in the following equation (6).

Y (t) = Vrf / Xpk × X (t) (4) = (X (t) / Xpk) × Vrf (5) X (t) / Xpk = 1 1 (6)

Therefore, the peak voltage Ypk of the output signal Y (t) can be expressed by the following equation (7), and the peak voltage Ypk of the output signal Y (t) may be equal to the reference voltage Vrf. Understand.

Ypk = Vrf (7)

That is, the signal level adjusting circuit 30 outputs the reference voltage V as the output of the multiplier 28 as shown in FIG.
An output signal Y (t) equal to or less than rf can be output. Further, since the signal level adjustment circuit 30 is configured by an analog circuit, the following effects can be obtained depending on the operable range.

That is, the analog circuit has a power supply voltage of +
In the case of the dual power supply system of Vcc (positive) and -Vcc (negative), the operable range of the signal voltage is limited from + Vcc to -Vcc by the power supply voltage (+ Vcc, -Vcc).
For example, when the power supply voltage Vcc is ± 15 V, the maximum value of all signal voltages in the circuit is +15 V or less, and the minimum voltage is −15 V.
It becomes 15V or more.

Therefore, when the power supply voltage Vcc of the signal level adjusting circuit 30 is set to, for example, ± 15 V, the reciprocal value (1 / X (t)) of the input signal X (t) becomes +15 V
If it is above, the output voltage is automatically clamped and +1
It becomes 5V. As a result, when the input amplitude becomes smaller than a certain value, the automatic level adjustment function does not operate,
The value of the output amplitude decreases as the input amplitude changes.
In other words, when the input signal X (t) is zero, the operation of infinitely amplifying and outputting noise is not performed, and only the input signal X (t) having a certain amplitude or more is automatically detected. , Which can control the gain.

Here, the input / output characteristics of the peak voltage Xpk of the input signal X (t) and the peak voltage Ypk of the output signal Y (t) will be described with reference to FIG. Vcc shown in FIG. 4 is the power supply voltage Vcc described above. As shown in FIG. 4, in the signal level adjustment circuit 30, the input signal X (t)
When the peak voltage Xpk exceeds the power supply voltage Vcc and when the reference voltage Vrf exceeds the power supply voltage Vcc, the output signal Y (t) is not output.

If the input signal X (t) is 1 or less even within a range not exceeding these values, the value of (1 / X (t)) becomes larger than 1, so the input signal X (t) ) Becomes smaller than a predetermined value, (1 / X (t)) becomes saturated and cannot operate. That is, when (reference voltage Vrf / input signal X (t)) is smaller than power supply voltage Vcc, signal level adjustment circuit 30 cannot operate. Thus, as described above, when the input signal X (t) is zero, a noise removing function can be exhibited.

As shown in FIG. 5, the reference voltage Vrf is set to various values (in FIG. 5, the reference voltage Vrf = 1V, 2V, 3V
V, 4 V, and 15 V), the operating range of the signal level adjustment circuit 30 can be arbitrarily set. Therefore, the signal level to be converted can be arbitrarily set by appropriately changing the setting of the reference voltage Vrf.

As described above, the signal level adjusting circuit 30
According to the above, an arbitrary function F (x) is to divide the reference voltage Vrf generated by the reference voltage source 22 by the peak voltage Xpk detected by the waveform preprocessing unit 34, so that the input signal The ratio of the reference voltage Vrf by the reference voltage source 22 to the peak voltage Xpk determined based on X (t) can be obtained.

Thus, the peak voltage Xpk becomes equal to the reference voltage Vpk.
When it is larger than rf, the operation result Z is 0 <Z <1.
Is obtained, and when the peak voltage Xpk is smaller than the reference voltage Vrf, a numerical value of Z> 1 is obtained as the calculation result Z. Therefore, when the operation result Z and the input signal X (t) are multiplied by the multiplier 28, an output equal to or lower than the reference voltage Vrf can be obtained as the output signal Y (t). That is,
Even if the input signal X (t) fluctuates, the output signal Y (t) below the reference voltage Vrf is formed without forming a feedback loop.
Can be converted to output the input signal X (t). Therefore, with a relatively simple configuration, the input signal X
There is an effect that the signal conversion processing for converting the input signal X (t) so as to output the output signal Y (t) equal to or lower than the reference voltage Vrf can be performed without lowering and deteriorating the accuracy of (t).

Subsequently, the aforementioned signal level adjusting circuit 30
Is applied to the marking signal extraction circuit 40 of the communication device, a configuration and the like will be described with reference to FIG. The marking signal extracting circuit 40 can be used as a circuit for extracting a predetermined marking signal from a received signal received from a power line in a receiving unit of a wired spread spectrum communication apparatus. For the configuration, operation, and the like of the wired spread spectrum communication device, refer to the specification and drawings attached to “Wired Spread Spectrum Communication Device and Communication Method” (Japanese Patent Application No. 2000-030116) by the present applicant.

As shown in FIG. 6, the marking signal extracting circuit 40 is different from the signal level adjusting circuit 30 in that a BPF 42 is provided in front of the input terminal 21 of the signal level adjusting circuit 30 described above.
The configuration is substantially the same as that of the signal level adjustment circuit 30 described above. Therefore, the same components as those of the signal level adjustment circuit 30 are denoted by the same reference numerals, and the description thereof will be omitted.

The BPF 42 connected to the input terminal 41
This is a so-called band-pass filter that allows a signal in a predetermined frequency band to pass therethrough and blocks a signal in other frequencies. Here, for example, the input signal X (t)
The frequency band allowing the passage of the marking signal X ′ (t) included in the baseband signal as described above is set in the BPF. Thus, a desired marking signal X '(t) can be extracted from the baseband signal X (t) by the BPF 42.

The output of the BPF 42 is supplied to the waveform preprocessing section 34.
And the multiplier 28 are connected. Therefore, the marking signal X ′ (t) extracted from the baseband signal X (t)
Is input to the waveform preprocessing unit 34 and the multiplier 28, respectively. That is, the marking signal X ′ (t) corresponds to the input signal X (t) of the analog signal conversion circuit 20 described above.

The marking signal X '(t) input to the waveform preprocessing section 34 is converted into an absolute value X' of the input signal X '(t) within a predetermined period (for example, one cycle) by the waveform preprocessing section 34.
ab (t) maximum value (> 0), that is, peak voltage Xpk of amplitude
Is detected (see FIG. 6).

Then, the peak voltage Xpk from the waveform preprocessing unit 34 and the reference voltage Vrf from the reference voltage source 22 are input to the function calculator 26. As a result, the function operation (F (x) = Vrf / Xpk) according to the above equation (1) is performed, and the multiplier 28 performs a multiplication operation of the calculation result Z and the marking signal X ′ (t). .

That is, according to the marking signal extraction circuit 40, the marking signal X '(t) extracted from the baseband signal X (t) is based on the marking signal X' (t) extracted by the waveform preprocessing unit 34. Determined peak voltage Xpk
Is detected, and a function (F (x) = V) in which the peak voltage Xpk and the reference voltage Vrf by the reference voltage source 22 are used as parameters.
rf / Xpk) is calculated by the function calculator 36 and the calculation result Z is output. The calculation result Z is multiplied by the marking signal X ′ (t) by the multiplier 28 to output the output signal Y.
Output as (t).

As a result, a function operation (F (x) = Vrf / Xpk) using the peak voltage Xpk determined based on the marking signal X '(t) and the reference voltage Vrf as parameters is performed, and the operation result Z is obtained. Since the marking signal X '(t) is multiplied, as described above, the output signal Y equal to or lower than the reference voltage Vrf is output.
The marking signal X ′ (t) can be converted to output (t). Therefore, the output signal Y (t) equal to or lower than the reference voltage Vrf can be output with a relatively simple configuration without causing the accuracy and deterioration of the marking signal X '(t) extracted from the baseband signal X (t). Thus, there is an effect that a signal conversion process for converting the marking signal X '(t) can be performed. Further, even if the signal level fluctuates due to the characteristics of the transmission line, etc., a stable marking signal X '(t) can be output as the output signal Y (t), so that the deterioration of the received signal and the decrease in S / N can be suppressed. There is an effect that can be done.

[Second Embodiment] Next, the configuration of an analog signal conversion circuit 50 according to a second embodiment of the present invention will be described with reference to FIG. The analog signal conversion circuit 50 according to the second embodiment includes an input signal X input to the waveform preprocessing unit 24.
1 (t) is different from the analog signal conversion circuit 20 according to the first embodiment in that the input signal X2 (t) input to the multiplier 28 is different.

As shown in FIG. 7, the analog signal input to the analog signal conversion circuit 50 is the input signal X1 (t) input to the waveform preprocessing section 24 via the first input terminal 51.
And an input signal X2 (t) input to the multiplier 28 via the second input terminal 53. That is, the multiplier 2
The analog signal input to 8 is another analog signal that is different from the analog signal input to the waveform preprocessing unit 24.

As described above, the input signal X 1 (t) input to the waveform pre-processing unit 24 and the input signal X 2 (t) input to the multiplier 28 are separated from each other, so that the multiplier 28 Then, the calculation result Z calculated and output by the function calculator 26 and the input signal X2 (t) input to the second input terminal 53
And multiply by

As a result, an arbitrary function operation using the detection voltage Vs and the reference voltage Vrf determined based on the input signal X1 (t) input to the first input terminal 51 as parameters is performed, and the operation result Z is obtained. Since the input signal X2 (t) input to the second input terminal 53 is multiplied, the input signal X2 (t) can be converted based on the signal information of the first input terminal 51. Therefore, even for such an input signal X2 (t), a relatively simple configuration has an effect of performing a desired signal conversion process without lowering or lowering the accuracy of the input signal X2 (t). is there.

Next, a configuration in which the analog signal conversion circuit 50 according to the second embodiment is applied to a baseband signal level adjustment circuit 60 of a communication device will be described with reference to FIG. The baseband signal level adjusting circuit 6
0 is also similar to the marking signal extraction circuit 40 described above.
It can be used for a receiving unit of a wired spread spectrum communication device.

As shown in FIG. 8, the baseband signal level adjusting circuit 60 has the BPF 42 of the marking signal extracting circuit 40 described in the first embodiment interposed between its input terminal 41 and the waveform preprocessing section 34. The configuration is substantially the same as that of the above-described marking signal extraction circuit 40 except that the configuration is adopted. Therefore, the same components as those of the marking signal extraction circuit 40 are denoted by the same reference numerals, and description thereof will be omitted.

The BPF 42 connected to the input terminal 61
For example, a frequency band allowing the passage of the marking signal X ′ (t) included in the baseband signal as the input signal X (t) is set. Thus, the baseband signal X (t) input via the input terminal 61 is
, A desired marking signal X ′ (t) is extracted, and output to the waveform pre-processing unit 34 at the subsequent stage.

On the other hand, the baseband signal X (t) input via the input terminal 61 is also input to the multiplier 28.
Thus, the multiplier 28 multiplies the input operation result Z by the function operation unit 36 with the baseband signal X (t) and outputs the result as an output signal Y (t).

As a result, a function operation (F (x) = Vrf / Vref / Prf) using the peak voltage Xpk determined based on the marking signal X '(t) extracted from the baseband signal X (t) and the reference voltage Vrf as parameters. Xpk), and the operation result Z
Is multiplied by the baseband signal X (t).
The baseband signal X (t) can be converted to output an output signal Y (t) having an amplitude based on rf. Therefore, even for such a baseband signal X (t), with a relatively simple configuration, the baseband signal X (t)
Signal conversion processing for converting a baseband signal X (t) so as to output an output signal Y (t) having an amplitude based on the reference voltage Vrf without causing a decrease in accuracy and deterioration of the signal. This also has the effect of suppressing deterioration of the received signal and reduction of S / N.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an analog signal conversion circuit according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a signal level adjustment circuit to which the analog signal conversion circuit according to the first embodiment is applied.

FIG. 3 is an explanatory diagram showing an example of a waveform of a signal processed by the signal level adjustment circuit according to the first embodiment;
Is a waveform example of the input signal X (t) within a predetermined period, FIG.
(B) shows the peak voltage X with respect to the input signal X (t) in FIG.
FIG. 3C is a waveform example of the result of calculating the reciprocal of the peak voltage Xpk, and FIG. 3D is (1 / Xpk) the reference voltage V
FIG. 3 (E) shows a waveform example of the result of multiplication by rf, and FIG. 3 (E) shows a waveform example of the output signal Y (t) of the multiplier.

FIG. 4 is an input / output characteristic diagram showing a relationship between a peak voltage Xpk of an input signal X (t) and a peak voltage Ypk of an output signal Y (t), which is processed by the signal level adjusting circuit according to the first embodiment. is there.

FIG. 5 shows the input / output characteristic diagram shown in FIG. 4 when various reference voltages (Vrf = 1V, 2V, 3V, 4V, and 15V) are set.

FIG. 6 is a block diagram illustrating an example in which the analog signal conversion circuit according to the first embodiment is applied to a marking signal extraction circuit of a communication device.

FIG. 7 is a block diagram illustrating a configuration of an analog signal conversion circuit according to a second embodiment of the present invention.

FIG. 8 is a block diagram illustrating an example in which the analog signal conversion circuit according to the second embodiment is applied to a baseband signal level adjustment circuit of a communication device.

[Explanation of symbols]

Reference Signs List 20, 50 Analog signal conversion circuit 22 Reference voltage source (DC voltage source) 24 Waveform preprocessing unit (DC voltage detector) 26 Function calculator 28 Multiplier 30 Signal level adjustment circuit 40 Marking signal extraction circuit 42, 42 BPF 60 Base Band signal level adjustment circuit X (t) input signal (input analog signal) X1 (t) input signal (input analog signal) X2 (t) input signal (other input analog signal) Vrf reference voltage ( Xs Detection voltage Xpk Peak voltage (Detection voltage) Z Calculation result Y (t) Output signal

Claims (5)

[Claims] 1. An analog signal conversion circuit for performing an arbitrary function operation on an input analog signal and outputting the result, wherein a DC voltage source for generating a predetermined DC voltage is determined based on the input analog signal. DC voltage detector for detecting a DC voltage to be supplied, a predetermined DC voltage generated by the DC voltage source and a detection voltage detected by the DC voltage detector are input, and an arbitrary function having both of them as parameters is calculated. A function calculator that outputs the calculation result, and a multiplier that inputs the calculation result by the function calculator and the analog signal, multiplies the two, and outputs an output signal. Analog signal conversion circuit. 2. The analog signal input to the multiplier is different from the analog signal input to the DC voltage detector and is another input analog signal. Analog signal conversion circuit. 3. The method according to claim 1, wherein the arbitrary function divides a predetermined DC voltage generated by the DC voltage source by a detection voltage detected by the DC voltage detector. 2. The analog signal conversion circuit according to 2. 4. A communication device using the analog signal conversion circuit according to claim 1, wherein the analog signal is an extracted signal extracted from a baseband signal, and the arbitrary function is determined by the DC voltage source. A communication device for dividing a predetermined DC voltage generated by a detection voltage detected by the DC voltage detector. 5. A communication device using the analog signal conversion circuit according to claim 2, wherein the analog signal is an extracted signal extracted from a baseband signal, and the other input analog signal is A communication device, wherein the communication device is a baseband signal, wherein the arbitrary function divides a predetermined DC voltage generated by the DC voltage source by a detection voltage detected by the DC voltage detector.