JPH07111520A - Receiver for superimposed modulation signal - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention relates to a receiver for a superposed modulation signal in a digital transmission system. [Structure] A symbol timing recovery unit that receives a superimposition modulated signal and outputs a symbol timing signal so that the cycle of the symbol timing signal is the same as the cycle of the superimposition modulated signal, and receives the symbol timing signal, and B + ( P
-B) Correlation signal generator that outputs a correlation signal of cos (2πt / T) (where B is a variable that can be adjusted, P is a predetermined maximum value, and T is a symbol period), and a superposition modulation An integrator that integrates the output of the correlation multiplier that multiplies the signal with the correlation signal for each symbol period is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data transmission system,
In particular, it relates to a receiver for receiving a superposed modulated signal in a digital transmission system.

[0002]

BACKGROUND OF THE INVENTION Binary data signals are typically modulated onto single carrier or quadrature carrier signals. At the final stage before transmission, high power amplification is performed by HPA (high power amplifier). For efficient operation of this high power amplifier, it is preferable to operate in the saturated mode, but in this case, the output of the amplifier becomes non-linear, in which case the high power amplifier generates many sidebands. , This sideband causes interference between channels. Therefore, there is a demand for a modulation method capable of solving the above problems while efficiently transmitting power and band, and as a realization of such a modulation method, Kimilo Feher's US Pat. No. 4,399. , 724, and Jong-soo Seo
And Kimilo Feher in U.S. Pat. No. 4,644,565.

In the above-mentioned US Pat. No. 4,399,724 and US Pat. No. 4,644,565, NRZ (non
A pulse type bit such as return to zero) is converted into an output signal corresponding to any one of four specific signals based on the previous bit and the current bit to be transmitted. In U.S. Pat. No. 4,399,724, the four particular signals are A cos (πt / T), -A, -A cos (πt / T) and A. However, A is an amplitude variable and T is a bit period. On the other hand, four specific signals in U.S. Pat. No. 4,644,565 are -A- (1-A) cos (2πt / T) and -cos (πt /
T), cos (πt / T) and A + (1-A) cos (2πt / T). Where A is the amplitude variable and T is the bit period. Such a modulation signal has continuity even at the bit transition point, and if there is no jitter, there is no interference between symbols. In addition, the latter modulation method can control the bandwidth of the transmitted signal to suit the transmission system by manipulating the amplitude variable A. A signal modulated by such a modulation method is called a superposition modulation signal.

A conventional receiver for a superposed modulated signal containing a noise signal will now be described. Conventional receivers include matched filter receivers and optimal receivers. Among them, the matched filter receiver includes a filter whose transfer characteristic matches the filter included in the transmitter, which reduces a noise signal in the received signal and maximizes the original signal. However, the transmitted signal contains complicated components as described above, and it is very difficult to realize a matched filter receiver with less noise. Therefore, a physical filter receiver is used instead of a matched filter receiver. An example of this physical filter receiver is a Butterworth filter where the 3 dB frequency or half power frequency is half the bit frequency.

However, conventional physical filters also require that their half power frequency settings be reset if the bit rate of the transmitter changes. That is, the inaccurate half-power frequency deteriorates the ratio Ed / No of the bit energy to the noise density, reduces the original signal component, and consequently increases the error rate. Thus, the half power frequency of the receiver needs to be finely set. Therefore, in order to improve this problem, a filter having a plurality of half-power frequencies and appropriately selecting from among the plurality of half-power frequencies according to the bit rate of the transmitter is disclosed. However, this type of filter requires a lot of birdware resources and therefore also increases the cost. Further, the characteristics of the conventional physical filter are changed according to the amplitude variable, that is, the superposition variable A. Therefore, the filter of the receiver in the conventional transmission system generally converts according to the bit rate of the transmitter.

The conventional optimum receiver as another receiver can reduce the error rate during demodulation. That is, in this optimum receiver, a correlation signal having a component equal to the baseband signal of the transmitted signal is generated and the received signal is compared with the correlation signal pulse during demodulation. The optimum receiver also transforms its transfer characteristic by adjusting the period of the correlation pulse to match the transmitter when the bit rate of the transmitter changes.

Here, the superposed modulated signal comprises a plurality of baseband signals, so that in order to realize an optimum receiver associated therewith, a plurality of generators each generating a baseband signal and a plurality of generators are provided. It requires multiple detectors to generate the observation signal. The optimum receiver also includes a selector for selecting any one of the observed signals. Thus, the structure of the optimum receiver is very complicated.

A second method for reducing such complexity
Optimal receivers are disclosed. It is based on a smaller baseband signal than the optimal receiver, which increases the error rate but improves the complexity of the structure. For example, the least convenient keying MSK optimal receiver can be used to demodulate it with a second optimal receiver of the superposed quadrature modulated signal. Here, the optimum receiver for MSK produces a plurality of correlation pulses associated with the MSK baseband signal, which is similar to the baseband signal of the superposed quadrature modulated signal. In particular, as the amplitude variable becomes smaller, the baseband signal of the superposed quadrature modulation signal becomes M
It is similar to the SK baseband signal and reduces the degree of mismatch between the transmitter and receiver of the superposed quadrature modulated signal. In other words, demodulation of the superimposed quadrature modulation signal is performed in exchange for the negligible deterioration of the error probability. Here, the smaller the amplitude variable, the smaller the error probability.

However, the bandwidth occupied by the superposed quadrature modulated signal in the frequency domain is increased due to the decrease of the amplitude variable A in the characteristics of the superposed quadrature modulated signal, thereby reducing the band efficiency. Here, the bandwidth occupied by MSK is wider than the bandwidth occupied by the superposed quadrature modulation signal, and M
It should be noted that SK has side lobes that cannot be ignored. Therefore, the second optimum receiver of the superposed quadrature modulated signal constructed on the basis of the MSK baseband signal has the matched transfer characteristic of the MSK transmitter.
Therefore, the bandwidth occupied by the second optimum receiver increases as the bandwidth occupied by the MSK transmitter increases, which causes the second optimum receiver to receive more adjacent channel signals. The error probability increases in channel transmission systems.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to achieve a bit rate (bit rat) which does not exceed a predetermined error probability and requires less hardware configuration than the conventional optimum receiver.
e) and to provide a receiver for superimposed modulated signals with flexibility according to the amplitude variable A. The receiver according to the invention is also resistant to interference between adjacent channel signals in a multi-channel transmission system and thus
As a result, the increase in error probability is suppressed.

[0011]

In order to achieve the object of the present invention, a symbol timing recovery means for extracting a timing signal from a received superimposed modulated signal and outputting a synchronized symbol timing signal, and the symbol timing signal. Correlation signal generating means for outputting a correlation signal having a B + (PB) cos (2πt / T) waveform based on the above equation (where B is a variable that can be adjusted, P is a predetermined maximum value, and T is a symbol period). ), A correlation multiplying unit for multiplying the superposed modulated signal by the correlation signal, and a unit for integrating the output of the correlation multiplying unit for each symbol period.

Further, means for receiving the superimposed modulated signal transmitted on the carrier wave, detecting the carrier wave from the received modulated signal and calculating a synchronized positive phase recovery carrier wave, and phase shifting the positive phase recovery carrier wave. A phase transition means for outputting a quadrature phase recovered carrier wave, a first carrier wave multiplication means for multiplying the superimposed quadrature modulated signal by the positive phase recovered carrier wave and outputting a positive phase superimposed modulation recovered signal, and the superimposed quadrature modulated signal Second carrier multiplication means for multiplying the quadrature phase recovered carrier wave and outputting a quadrature phase superimposition modulation recovery signal, and any one of the positive phase and quadrature phase superposition modulation recovery signal as input and synchronized symbols A symbol timing recovery means for outputting a timing signal, a first correlation signal of B + (PB) cos (2πt / T) and B- (P-
B) Correlation signal generating means for generating a second correlation signal of cos (2πt / T) (where B is an adjustable variable, P is a predetermined maximum value, T is a symbol period), and First correlation multiplication means for multiplying the positive phase superimposed modulation restoration signal by the first correlation signal, second correlation multiplication means for multiplying the quadrature phase superimposed modulation restoration signal by the second correlation signal, and the first correlation multiplication It is configured such that it comprises a first integrating means for integrating the output of the means for each symbol cycle, and a second integrating means for integrating the output of the second correlation multiplying means for each symbol cycle.

[0013]

[Operation] In the receiver according to the present invention, the period of the correlation signal generated in the receiver changes depending on the symbol period of the transmitted signal, that is, the symbol speed, and the variable [B] changes according to the control signal.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a configuration block diagram of a receiver according to the present invention. This receiver includes a carrier recovery unit 101, a carrier multiplier 102, a symbol timing recovery unit 103,
Correlation signal generator 104, correlation multiplier 105 and integrator 1
It is composed of 06.

In FIG. 1, a signal transmitted and received on a carrier wave is received by a carrier wave recovery section 101. The carrier recovery unit 101 extracts and outputs a synchronized recovered carrier from the received signal, and these are constructed based on the conventional technique. That is, the carrier recovery unit 101 detects a high frequency component from the received signal, and extracts and outputs a recovered carrier having a frequency and a phase that match the frequency and the phase of the carrier used in the transmitter.

The received signal is also a carrier multiplier 102.
And is multiplied by the recovered carrier. Here, if there is no noise mixed in the received signal, the output of the carrier wave multiplier 102 becomes any one of the baseband signals of the superimposed modulation signal. When noise is mixed, the output of the carrier multiplier 102 includes one of the baseband signals of the superposition modulation signal and an unnecessary harmonic component. The symbol timing recovery unit 103 operates the output of the carrier wave and outputs the symbol timing signal. The symbol timing signal is a sine-waveform signal whose period is T. In other words, the symbol timing signal is represented by cos (2πt / T). Here, t is the time varying from “0” to “T”, and the period T is similar to the period of the baseband signal included in the received signal. Correlation signal generator 104 receives the symbol timing signal and outputs a correlation signal represented by (PB) cos (2πt / T). Here, B is a variable that changes according to the control signal, and P is a predetermined maximum value.

The correlation multiplier 105 is a carrier multiplier 102.
After receiving the output and the correlation signal B + (PB) cos (2πt / T), the former is multiplied by the latter. Therefore, if the output of the carrier multiplier 102 matches the correlation signal B + (PB) cos (2πt / T) and has the same polarity, the correlation multiplier 105 maximizes the output signal energy. On the other hand, if the output of the carrier multiplier 102 matches the correlation signal B + (PB) cos (2πt / T) but has the opposite polarity, the output energy of the correlation multiplier 105 is minimized.

The integrator 106 integrates the output of the correlation multiplier 105 for each symbol period. That is, the output of the integrator 106 is reset at the initial point of the symbol period. Integrator 1
The output of 06 is also called the integral annihilator. This integrator 1
The output of 06 is sent to the decision device for decoding the original data corresponding to the data modulated by the transmitter.

2A to 2C are diagrams showing the waveform of the correlation signal output from the correlation signal generator 104 according to the variable [B] and the maximum value [P]. Of these, FIG. 10A is a waveform diagram of the correlation signal when the variable [B] is “0”, that is, the correlation signal is represented by Pcos (2πt / T). Further, FIG. 7B shows the waveform of the correlation signal represented by B + (PB) cos (2πt / T). Furthermore, Figure (c) shows B- (PB) c
FIG. 7 is a waveform diagram of a correlation signal represented by os (2πt / T). The correlation signal B- (PB) cos (2πt / T) is generated from the correlation signal generator 104 included in the receiver for the MSK signal, and the configuration of this receiver is shown in FIG.

FIGS. 3A and 3B and FIGS. 4A and 4B are waveform diagrams of the baseband signal, that is, the superimposed modulation signal. In particular, the superimposed modulation signal is expressed as follows. 3 (a) is A + (1-A) cos (2πt / T), FIG. 3 (b) is cos (πt / T), and FIG. 4 (a) is , -Cos (πt / T), and the diagram (b) of FIG.
-A- (1-A) cos (2πt / T). Such a baseband signal, that is, a superimposed modulation signal, is output by the carrier wave multiplier 102 shown in FIG. 1 if the received signal is free of noise.

Referring again to FIGS. 2 (a) to 2 (c), the correlation signals are shown in FIGS. 3 (a) and 3 (b) and FIGS. 4 (a) and 4 (b). Not exactly matched to any one of the baseband signals. However, since the amplitude can be adjusted by the variable [B], the degree of mismatching with all baseband signals is consequently equalized. Also, the receiver has a symbol rate,
That is, it has flexibility with respect to the bit rate, because the period of the correlation signal B + (PB) cos (2πt / T) follows the period of the symbol timing signal, which is similar to the period of the symbol period at the transmitter. .

If the output of the correlation multiplier 105 is integrated by the integrator 106 for one symbol period, the unnecessary harm contained in the output of the carrier wave multiplier 102 is obtained.
The onic component is removed and the original signal energy is output. Here, if the output of the integrator 106 is larger than "0", the received information is decoded into "1". On the contrary, if the output of the integrator 106 is smaller than "0", the received information is decoded into "0". Further, the output of the integrator 106 is reset to the initial value of the symbol period, so that the signal energies of the symbols do not interfere with each other.

FIG. 5 is a graph showing the deterioration of Eb / No with respect to the variable [B] of the receiver due to the amplitude variable [A] of the transmitter. In particular, the variable [B] is 0.6 and the amplitude variable [A]
Is 0.6, under the condition that the error probability [P _e ] is 1 × 10 ⁻⁴ , the ratio of bit energy to noise density Eb /
No shows deterioration of 0.1 dB or less as compared with the optimum receiver. On the other hand, if the variable [B] is 0.6 and the amplitude variable [A] is 1.0, the ratio of bit energy to noise density E
b / No deteriorates by about 0.7 dB. In such a case, if the variable [B] is changed to 0.8 under the condition that the amplitude variable [A] of the superposition modulation signal is 1, the deterioration of the ratio Eb / No of the bit energy to the noise density is deteriorated. Is 0.35
It becomes dB. Further, as shown in FIG. 5, in the receiver according to the present invention in which the variable [B] is 0.6, the MSK signal can be demodulated with negligible error probability deterioration.

FIG. 6A is a graph showing the normalized power spectrum energy density with respect to the normalized frequency in the receiver according to the present invention. FIG. 6 (b) is a graph showing the normalized power spectral density with respect to the normalized frequency in the conventional optimum receiver for the MSK signal. As shown in FIGS. 6 (a) and 6 (b), the power spectral density of the receiver according to the present invention has a bandwidth in the frequency domain which is narrower than the bandwidth of the optimum receiver for the MSK signal. Have. In other words, the majority of the superposed modulated signal has frequency components contained within the frequency band 1 / T, which causes the receiver of the present invention to have a range of original signals more than the conventional optimum receiver for MSK signals. Reception of external noise components is reduced, and adjacent channel interference is reduced.

FIG. 7 shows the correlation signal generator 1 shown in FIG.
FIG. 4 is a detailed block diagram of 04. This correlation signal generator 1
04 comprises a reference signal generator 601, an amplifier 602, a subtractor 603, a multiplier 604 and an adder 605. That is, the reference signal generator 601 generates a reference signal whose level is P, and sends this reference signal to the amplifier 602 and the subtractor 603. The amplifier 602 amplifies the P reference signal and outputs the B signal, and its gain is smaller than 1 and is controlled by the control signal. This control signal is generated based on the characteristics of the transmission system. That is, it is generated by the operation of the transmission system designer. Further, the subtractor 603 subtracts the B signal from the P reference signal.
The multiplier 604 receives the output of the subtractor 603 and the symbol timing signal, multiplies the former by the latter, and outputs the existing correlation signal. The adder 605 receives the B signal and the basic correlation signal, adds the former and the latter, and outputs the correlation signal.

FIG. 8 is a detailed block diagram of the integrator 106 shown in FIG. The integrator 106 has a low pass filter 701, a switch SW, a monostable multivibrator Q2, and a converter Q1. The low pass filter 701 has a resistor R and a capacitor C. In FIG. 8, the low pass filter 701 is shown.
Receives the output of the correlation multiplier 105 shown in FIG. 1, performs low-pass filtering, and integrates the output. The switch SW is periodically "on" for a very short period of time to discharge the output node of the low pass filter 701. The switch SW may be a transistor connected between the low pass filter 701 and the ground.

The converter Q1 converts the symbol timing signal having a sine waveform into a rectangular wave signal. The monostable multivibrator Q2 receives a rectangular wave signal and outputs a trigger signal, and this trigger signal is sent to the switch SW as a switching control signal. That is, the switch SW
Receives a trigger signal and performs a switching action. This trigger signal is activated at the initial point of the symbol period.

FIG. 9 is a block diagram showing the structure of a receiver for superposed quadrature modulation signals such as MSK signals according to the present invention. This receiver includes a carrier recovery unit 801, carrier multipliers 802, 804, a phase shifter 803, and a correlation multiplier 8.
07, 808, symbol timing recovery unit 805, correlation signal generator 806, and integrators 809, 810. Transmission channels for superposed quadrature modulated signals include positive-phase channels and quadrature-phase channels, which theoretically have twice the band efficiency as compared to transmission channels having only positive-phase channels.

The carrier recovery unit 801 in FIG.
It is the same as the one shown in the above, and outputs a positive phase recovery carrier wave. The phase shifter 803 receives the positive phase recovered carrier, performs phase transition by about 90 °, and outputs a quadrature recovered carrier. The carrier multiplier 802 multiplies the received signal by the positive phase recovery carrier. Carrier wave multiplier 804
Multiplies the received signal with the quadrature recovery carrier. The symbol timing restorer 805 is similar to that shown in FIG. 1 and receives one of the outputs from the carrier multipliers 802 and 804. Correlation signal generator 8
06 manipulates the symbol timing signal to produce B + (PB) cos
The first correlation signal represented by (2πt / T) and B- (PB) cos (2π
The second correlation signal represented by t / T) is output. Correlation multiplier 8
07 is the output of the carrier multiplier 802 and B + (PB) cos (2π
The first correlation signal represented by t / T) is multiplied. Multiplier 808
Is the output of the carrier multiplier 804 and B- (PB) cos (2πt / T)
The second correlation signal represented by is multiplied. Integrators 809, 8
Reference numeral 10 is similar to the integrator 106 shown in FIG. 1 and has the same configuration as that shown in FIG. Integrator 809
Outputs the result by integrating the output of the correlation multiplier 807, which is reset at the initial point of every symbol period. On the other hand, the integrator 810 integrates the output of the correlation multiplier 808 and outputs the result, and this output is reset at the initial point of each symbol period.

FIG. 10 shows the correlation signal generator 80 shown in FIG.
6 is a detailed block diagram of the reference signal generator 901,
It has an amplifier 902, subtractors 903, 906, a multiplier 904 and an adder 905. Reference signal generator 901, amplifier 902, subtractor 903, multiplier 904 and adder 905 shown in FIG. 10 are reference signal generator 601, amplifier 602, subtractor 603 and multiplier 604 shown in FIG.
And adder 605, respectively. The subtractor 906 receives the B signal on the drawing, subtracts the basic correlation signal, and outputs a second correlation signal represented by B- (PB) cos (2πt / T).

FIG. 11 is a graph showing the amplitude variable [A] and the error probability for the ratio Eb / No of the bit energy to the noise density according to the variable [B] in the receiver according to the present invention. In FIG. 11, a code G1 is a variable [B] for the receiver for the superposed quadrature modulation signal whose amplitude variable is [A].
Shows the deterioration of the error probability when 0.8, and the code G2 is
Reference numeral G3 indicates that the amplitude variable [A] is 0.8. The receiver has a variable [B] of 0.6 for the superposed quadrature modulation signal of 6
3 shows the deterioration of the error probability when having. Reference symbol G4
Shows the degradation of error probability in an ideal Nyquist channel. According to FIG. 11, a suitable variable [B] for an arbitrary amplitude variable [A] has a bit energy to noise density ratio Eb / No of 0.5d under an error probability of 1 × 10 ^−4.
B or less is brought about.

FIG. 12 is a graph showing the deterioration of the error probability with respect to the channel spacing. If the transmitted signal is a superposed quadrature modulated signal with an amplitude variable of 0.6, code G5 is for an optimal receiver for MSK signals and code G6 is a variable [B] of 0.6. For a receiver of the invention having On the other hand, if the transmitted signal is a superposed quadrature modulation signal with an amplitude variable of 0.8, code G7 relates to the optimum receiver for the MSK signal and code G8 is a variable of 0.7. It relates to the receiver of the present invention having [B]. Thus, when the receiver of the present invention is compared to the conventional optimum receiver for MSK signals, the degradation of the bit energy to noise density ratio Eb / No decreases with decreasing channel space. That is, the receiver of the present invention is resistant to adjacent channel interference.

[0033]

INDUSTRIAL APPLICABILITY The present invention is B + (PB) cos (2πt / T) or
B- (PB) cos (2πt / T) correlation signal generator that generates a correlation signal makes it possible to achieve a bit rate with less hardware configuration than the conventional optimum receiver without exceeding a predetermined error probability. (bit rate) and amplitude variable A for flexibility (f
It is possible to realize a receiver of superimposed modulation signals having lexibility). In addition, in a multi-channel transmission system, there is resistance to interference between adjacent channel signals, so that a receiver for superimposed modulation signals that can suppress an increase in error probability can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a general configuration of a receiver according to the present invention.

2A to 2C show waveforms of a correlation signal output from a correlation signal generator according to a variable [B] and a maximum value [P].

3A and 3B are waveform diagrams of a baseband signal, that is, a superimposed modulation signal.

FIG. 4A and FIG. 4B are also waveform diagrams of a baseband signal, that is, a superimposed modulation signal.

FIG. 5 is a graph showing the deterioration of Eb / No with respect to the variable [B] of the receiver due to the amplitude variable [A] of the transmitter.

FIG. 6 (a) is a graph showing normalized power spectral density with respect to normalized frequency in a receiver according to the present invention, and FIG. 6 (b) is a conventional optimum receiver for MSK signals. 6 is a graph showing a normalized power spectral density with respect to a normalized frequency.

7 is a detailed block diagram of the correlation signal generator shown in FIG. 1. FIG.

FIG. 8 is a detailed block diagram of the integrator shown in FIG.

FIG. 9 is a block diagram showing a configuration of a receiver for a superposed quadrature modulation signal according to an MSK signal according to the present invention.

10 is a detailed block diagram of the correlation signal generator shown in FIG. 9. FIG.

FIG. 11 shows the ratio E of the bit energy to the noise density according to the amplitude variable [A] and the variable [B] in the receiver according to the invention.
It is a graph which shows the error probability with respect to b / No.

FIG. 12 is a graph showing deterioration of error probability with respect to channel spacing.

[Explanation of symbols]

 101-Carrier restoration unit 102-Carrier multiplier 103-Symbol timing restoration unit 104-Correlation signal generator 105-Correlation multiplier 106-Integrator 601-Reference signal generator 602-Amplifier 603-Subtractor 604-Multiplier 605- Adder 701, low-pass filter 801, carrier recovery unit 802, carrier multiplier 803, phase shifter 804, carrier multiplier 805, symbol timing recovery unit 806, correlation signal generator 807, correlation multiplier 808, correlation multiplier 809-Integrator 810-Integrator 901-Reference signal generator 902-Amplifier 903-Subtractor 904-Multiplier 905-Adder

Claims (13)

[Claims] 1. A symbol timing recovery means for extracting a timing signal from a received superimposed modulated signal and outputting a synchronized symbol timing signal, and B + (PB) cos (2π) based on the symbol timing signal.
(t / T) correlation signal generating means for outputting a correlation signal (where B is a variable that can be adjusted, P is a predetermined maximum value, T is a symbol period), and the superimposed modulation signal is A receiver for a superimposed modulation signal, comprising: correlation multiplication means for multiplying a signal; and means for integrating the output of the correlation multiplication means for each symbol period. 2. A means for receiving a superimposed modulated signal transmitted on a carrier wave, detecting a carrier wave from the received signal to calculate a synchronized restored carrier wave, said transmitted signal and said restored carrier wave. 2. The receiver for superposed modulated signals according to claim 1, further comprising carrier wave multiplication means for multiplying by. 3. The correlation signal generating means is means for generating a maximum value signal having a level of P, and the amplification factor is adjusted to be less than 1 when the maximum value signal is amplified to calculate a variable signal. Possible means, means for subtracting the variable signal from the maximum value signal to calculate an amplitude signal, means for multiplying the amplitude signal with the symbol timing signal to output a basic correlation signal, and the variable signal 2. A means for adding the basic correlation signal and the basic correlation signal to calculate the correlation signal is provided.
A receiver for the superimposed modulated signal as described. 4. The receiver for superimposed modulation signals according to claim 1, wherein the symbol timing recovery means generates a symbol timing signal having a sine waveform. 5. The means for integrating comprises means for converting the symbol timing signal into a rectangular wave signal having the same period, and a trigger for receiving the rectangular wave signal and having the same period as the rectangular wave signal. A monostable multivibrator for generating a signal, a low-pass filter means for low-pass filtering the output from the correlation multiplication means, and a low-pass filter means connected between the output of the low-pass filter means and ground. The receiver of the superimposed modulation signal according to claim 1, further comprising switching means for switching based on the trigger signal. 6. The low pass filter means comprises a resistor having one end connected to the correlation multiplication means, and a capacitor connected between the other end of the resistor and ground. Item 7. A receiver for superimposed modulation signals according to Item 5. 7. A receiver for a superimposed quadrature modulation signal transmitted on a carrier wave, receiving the transmitted signal, detecting the carrier wave, and outputting a synchronized positive phase recovery carrier wave, Phase transition means for phase-shifting the positive phase recovered carrier and outputting a quadrature recovered carrier; first carrier multiplication for multiplying the superimposed quadrature modulated signal by the positive phase recovered carrier to output a positive phase superimposed modulated recovered signal Means for outputting the quadrature phase superimposition modulation restoration signal by multiplying the superposition quadrature modulation signal by the quadrature phase restoration carrier wave; and one of the positive phase and quadrature phase superposition modulation restoration signals. A symbol timing recovery means for inputting and outputting a synchronized symbol timing signal, and receiving the symbol timing signal, B + (PB) cos (2π
Correlation signal generating means for generating a first correlation signal of t / T waveform and a second correlation signal of B- (PB) cos (2πt / T) waveform (however, B
Is a variable that can be adjusted, P is a predetermined maximum value, and T is a symbol period), a first correlation multiplication means for multiplying the positive phase superposition modulation restoration signal by the first correlation signal, and the quadrature. Second correlation multiplication means for multiplying the phase superposed modulation restoration signal by the second correlation signal, first integration means for integrating the output of the first correlation multiplication means for each symbol period, and output of the second correlation multiplication means A receiver for superposed modulated signals, characterized in that it comprises a second integrating means for integrating the signal for each symbol period. 8. The correlation signal generating means is a means for generating a maximum value signal having a level of P, and an amplification degree is adjustable to be less than 1 by amplifying the maximum value signal and outputting a variable signal. A means for multiplying the amplified signal by the symbol timing signal,
A unit for outputting a basic correlation signal; a unit for adding the variable signal and the basic correlation signal to output a first correlation signal; and a unit for subtracting the basic correlation signal from the variable signal and outputting a second correlation signal. 8. The receiver for superimposed modulation signals according to claim 7, further comprising means. 9. The receiver of the superimposed modulation signal according to claim 7, wherein said symbol timing restoration means outputs a symbol timing signal having a sine waveform. 10. The first integrating means converts the symbol timing signal into a rectangular wave signal having a cycle similar to that of the symbol timing signal, and receives the rectangular wave signal to determine a cycle of the rectangular wave signal. A monostable vibrator that outputs a trigger signal that is the same as a rectangular wave signal; a low-pass filter unit that receives the output of the first correlation multiplying unit and performs low-pass filtering; a low-pass filter unit and ground. The receiver of the superimposed modulation signal according to claim 7, further comprising a switching unit connected between the two and switching according to the trigger signal. 11. The low pass filter means comprises a resistor having one end connected to the correlation multiplication means, and a capacitor connected between the other end of the resistor and ground. Item 10. A receiver for superimposed modulation signals according to Item 10. 12. The second integrating means converts the symbol timing signal into a rectangular wave signal whose period is the same as the period of the symbol timing signal, and the second integrating means receives the rectangular wave signal and changes its period. A monostable multivibrator that outputs a trigger signal similar to a rectangular wave signal, a low-pass filter unit that receives the output of the second correlation multiplying unit and low-pass filters the low-pass filter unit, and a ground. Is connected between
The receiver of the superimposed modulation signal according to claim 7, further comprising a switching unit that switches according to the trigger signal. 13. The low pass filter means comprises a resistor having one end connected to the correlation multiplying means, and a capacitor connected between the other end of the resistor and ground. Item 13. A receiver for superimposed modulation signals according to Item 12.