JPH0226188A - Multiplex transmission signal reproducing device - Google Patents

Abstract

PURPOSE:To stabilize the reproducing of a signal by providing an interference detecting circuit and a control circuit, detecting a signal to be the interference of a signal, which is multiplex transmitted, and efficiently decreasing the interference. CONSTITUTION:For a multiplex signal, a multiplex signal band is extracted by a band pass filter 115 for extraction from the output of a frequency converting circuit 113 and inputted to a frequency converting circuit 116. A signal band is selected through a band pass filter 118 by the circuit 116 and converted to an intermediate frequency, whose frequency is further low. For the intermediate frequency, synchronized with a carrier, which is reproduced by a carrier reproducing circuit 120, is used in a synchronization detecting circuit 119 and a demodulated signal is outputted. On the other hand, the output of the circuit 119 is inputted to an interfering output circuit 123 and an interference level from the video signal to the multiple signal is detected. Then, an interference detecting signal is outputted to a control circuit 124. The circuit 124 controls the output frequency of a first or second local oscillating circuit, which determines the outputs of the circuits 116 and 119, and efficiently decrease the interference.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multiplex transmission system, and more particularly to a multiplex transmission signal reproducing apparatus for receiving all transmission signals in which other information is multiplexed on a current television signal.

[Conventional technology]

Conventionally, a method for multiplexing other information in a television broadcast signal was to modulate a carrier wave having an orthogonal phase relationship with the video carrier wave with other information, as described in Japanese Patent Laid-Open No. 49-84728, and then modulate the signal with the video signal. An orthogonal modulation method was known in which the signal is combined with a video carrier wave and transmitted.

In addition, as a method for reducing interference caused by multiplexed signals to current TV receivers using this orthogonal modulation method, the Incorporated Association Electronics Co., Ltd. Published by the Institute of Communication Engineers, Institute of Electronics and Communication Engineers Technical Research Report, Vol. 86 No.
246, pages 65 to 72, November 27, 1986, communication system CSS6-82 "Transmission of high-definition images by orthogonal modulation of video carrier waves" is discussed.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into account the reduction of interference from the video signal to the multiplex signal when reproducing the multiplexed signal that has been multiplexed, and has the problem of causing interference to the multiplex signal.

An object of the present invention is to provide an orthogonal modulation method that reduces interference with current television multiplexed broadcasts, and to reduce interference from video signals (and stabilize An object of the present invention is to provide a multiplex transmission signal reproducing device that is effective for receiving and reproducing signals.

[Means to solve the problem J The above purpose is to provide an amplitude modulated carrier wave and its propagation.

A local oscillator used to convert the orthogonal multiplexed transmission signal to an intermediate frequency in a receiver that demodulates the multiplexed signal from the orthogonal multiplexed transmission signal transmitted by combining the transmitted wave and the multiplexed signal modulated by f in an orthogonal relationship. This is accomplished by adjusting the frequency of the amplitude modulated telephonic carrier to minimize interference with the multiplexed signal.

Furthermore, this can be achieved by adjusting the characteristics of a band-pass filter that extracts the entire multiplex signal band from the orthogonal multiplexed transmission signal so as to minimize the interference from the amplitude-V modulated carrier wave to the multiplex signal.

[Effect]

The intermediate frequency is controlled so as to best correct the deviation of the center frequency from the ideal characteristic and the deviation of the shoulder characteristic of the bandpass filter that extracts the multiplexed signal band from the t-orthogonal multiplexed transmission signal converted into the intermediate frequency. As a result, the bandpass characteristics operate so as to approach the ideal transmission path characteristics, so that interference from the amplitude modulated carrier wave to the multiplexed signal is minimized, and stable demodulation can be performed.

Furthermore, the transmission characteristics are controlled so that the ripples of the bandpass filter are most corrected. As a result, the bandpass characteristics operate so as to approach ideal transmission path characteristics, so that interference from the amplitude modulated carrier wave to the multiplexed signal is minimized (and stable demodulation can be performed).

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows an example of a receiver that multiplexes signals to the current terrestrial television broadcasting system.

101 is an antenna, 102 is a high frequency amplification circuit, 105 is a reproduction IF filter, 104 is an intermediate frequency amplification circuit, 105
106 is a video signal detection circuit, 106 is a video signal amplification circuit, and 10 is a video signal detection circuit.
7 is a color difference signal demodulation circuit, 108 is a primary color signal demodulation circuit, 1
09 is a cathode ray tube +5110 is an audio intermediate frequency amplification circuit,
111 is an audio FM detection circuit, 112 is an audio signal output terminal, 113 is a first frequency conversion circuit, 114 is a first local oscillation/oscillator circuit, 115 is a band-pass filter for extracting multiplexed ratio signals, and 116 is an audio signal output terminal. a second frequency conversion circuit, 117 a second local oscillation circuit, 118 a band pass filter, 119
121 is a signal processing circuit; 122 is a multiplexed ratio signal output terminal; 123 is a synchronous detection circuit;
124 is a control circuit for controlling the oscillation frequency of the local oscillation circuits 114 and 117.

The television signal inputted from the antenna 101 is amplified by the high frequency amplification circuit 102, and the signal is amplified by the first frequency conversion circuit 113.
The frequency is converted into an intermediate frequency for demodulation, and the intermediate frequency amplification circuit 104 amplifies the frequency. Tuning is performed by changing the local oscillation frequency of the frequency conversion circuit 113. The video signal band from the amplified signal of the intermediate frequency amplification circuit 104Z is detected by the video signal detection circuit 105, and a primary color signal is obtained from the luminance signal output from the video signal amplification circuit 106 and the color difference signal output from the color difference signal demodulation circuit 107. In the demodulation circuit 108,
The three primary colors of B are obtained and projected onto a cathode ray tube 109.

The audio signal band is amplified by an audio intermediate frequency amplification circuit 110, detected and demodulated by an audio FM detection circuit 111, and an audio signal is obtained at an audio signal output terminal 112.

The above is the same as the conventional TV SILON receiver.

In addition to the above, in order to demodulate the multiplexed signal, the extraction bandpass filter 115 extracts the multiplexed signal band from the output of the first frequency conversion circuit 113, and the output t - the second frequency conversion circuit 116 The signal is then frequency-converted, passed through a band-pass filter 118, and the multiplexed signal band is selected and converted into an intermediate frequency with a lower frequency. Synchronized with the carrier wave, the signal is modulated by a component orthogonal to the f subcomponent using a signal gold, and a ratio signal is detected and demodulated. The resulting ratio signal is processed by a signal processing circuit 121 to return the source signal to an output terminal 122. Ten thousand.

The output of the synchronous detection circuit 119 is input to the interference detection circuit 123, which detects interference by checking the level of interference from the video signal to the multiplexed signal, and outputs the interference detection signal to the control circuit 124. The control circuit 124 is.

The first local oscillation circuit and the second local oscillation circuit are controlled by the interference detection signal, and the center frequency deviation and cantilever deviation from the ideal characteristics of the extraction band-pass filter 115, the band-pass filter, etc. are corrected, It approximates ideal transmission path characteristics and works to minimize interference from video signals.

There are several possible operations of the control circuit 124 as shown below. That is, suppose that the first intermediate frequency f3 is obtained by the first frequency conversion circuit 113, and the second intermediate frequency f is obtained by the second frequency conversion circuit 116.

(11 The local oscillation circuit 114.1 changes only the first intermediate frequency f, and does not change the second intermediate frequency f.
17. By controlling in this way, only the characteristics of the extraction band-pass filter 115 can be corrected,
Interference from video signals can be reduced.

(21) The local oscillation circuit 114 fixes the first intermediate frequency and changes the second intermediate frequency f and height.
117. By controlling in this way, it is possible to correct only the characteristics of the bandpass filter 118, or to neutralize the interference from the video signal that occurs at the performance limit of the synchronous detection circuit 119, carrier wave regeneration circuit 120, etc. , interference from video signals can be reduced.

(31 second intermediate frequency fst - fixed, local oscillation circuit 11 so that only the first intermediate frequency f is changed)
4゛, 117 is controlled. By controlling in this way,
Extraction bandpass filter 115, second frequency conversion circuit 116, bandpass filter 118, synchronous detection circuit 119
, the interference from the video signal that occurs due to the performance limit of the carrier wave regeneration circuit 120, etc. can be neutralized, and the interference from the video signal can be reduced.

By using the above 111, (21, and (31i) in combination, interference from video signals can be efficiently reduced.

According to this embodiment, the intermediate frequency of the output of the first frequency conversion circuit 113 (58.
The video signal is demodulated at a frequency of 75 MHz, which is commonly used), and the multiplexed signal is demodulated using a lower intermediate frequency (for example, 5 MHz frequency) output from the second frequency conversion circuit 116. 4, the phase error caused by the circuit delay time of the carrier wave regenerated by the carrier regeneration circuit 120 used in the synchronous detection circuit 119 is reduced by lowering the frequency, and a highly accurate SAW filter is used as the extraction band-pass filter. can be used, and further the above (1)
, (2).

Since the method of No. 131 can reduce interference from video signals, it has the effect of stably demodulating multiplexed signals.

An embodiment of a transmitter that generates the signal transmitted in the above embodiment t-I! Shown in Figure 2. 201 is an audio signal terminal; 2
02 is an FM modulator, 203 is an audio signal carrier generator, 2
04 is a video signal human power line, 205 is a matrix circuit,
206 is a luminance signal processing circuit, 207 is a color difference signal processing circuit, and 208 is an addition circuit.

209 is a video modulator, 210 is a video signal carrier generator,
211 is a multiplexed signal input terminal, 212 is a signal processing circuit,
213 is a 90 degree phase shifter, 214 is a modulator for multiplexed signals,
215 is an adder, 216 is a V8 keyed to the vestigial sideband width.
B filter, 217 is an adder, 218 is an antenna, 21
9 is an equalizer.

The audio signal from the audio signal generator 201 is used to convert the audio carrier wave from the audio signal carrier generator 203 into the FM modulator 202.
FMlf tone. A matrix 205 divides the three GB primary color signals input to the video input terminal 204 into a luminance signal and a color difference signal, and a luminance signal processing circuit 206 for each.
After processing in the color difference signal processing circuit 207, the adder 208
Add with . The video signal carrier generator 21 uses the signal after addition.
Modulate the carrier wave from 0 using a video modulator 209ft, L
The V8B filter 216 limits the band to the television broadcasting band, and the adder 217 adds it to the audio signal and sends it to the antenna 21.
8 to 11! do.

The above is the same as the conventional terrestrial transmission of Television Giron broadcasting. Add the following to multiplex transmit other signals to the above signals.

The signal to be multiplexed is added to the input 1 child 211, and the signal processing circuit 2
12, the signal processing and band-limiting
Equalizer 2 with inverse characteristics to P's Nyquist filter
The frequency characteristics are corrected in step 19, and added to the carrier wave modulated by the video signal in adder 215. As a result, the video carrier wave is modulated in an orthogonal relationship with the video signal and the multiplexed signal.

Another embodiment of the invention is shown in FIG. FIG. 3 shows an example in which the multiplexed signal is digitally transmitted audio (abbreviated as PCM audio), and the same symbols as in FIG. 1 indicate the same functions.

501 is a band-pass filter for PCM audio extraction, 302 is a code identification circuit, 605 is a clock regeneration circuit, 504 is a digital signal processing circuit, 605 is a digital-to-analog conversion circuit (hereinafter abbreviated as DAC), and 506 is a digitally transmitted audio signal. This is a signal output terminal.

The difference between Fig. 5g3 and Fig. 1 is that the demodulated output of the synchronous detection circuit 119 is converted into a digital code by using the full code identification circuit 302ft with a low error rate, and the digital signal processing circuit 30
4, errors occurring during transmission are detected and corrected using an error detection and correction code. The clock recovery circuit 305 is a circuit that extracts a transmission lock from the output signal of the synchronous detection circuit 119, and digitally encodes the output signal of the synchronous detection circuit 119 at a point where the error rate is low (the so-called maximum opening of the eye pattern). It is necessary to do so. After error detection and correction, the digital signal t-Dkc 505 is converted into an analog signal and returned to an audio signal, which is then obtained at an output terminal 306 for a digitally transmitted audio signal.

According to this embodiment, the effect of stably demodulating a digitally transmitted audio signal is achieved as in FIG. 1.

FIG. 4 shows an embodiment of a transmitter that generates all the signals transmitted in the embodiment of FIG. 3. The same symbols as in Figure g2 indicate the same functions. 401 is an input terminal for audio signals to be digitally transmitted;
402 is an analog-to-digital converter (hereinafter abbreviated as ADC), 40! I is a digital (g processing circuit), and 404 is a low-pass filter.

The audio signal to be multiplexed is added to the input terminal 401, converted into a digital signal by the audio signal sound ADc 402, and a code L4 for detecting and correcting r49 occurring during transmission is added to the digital signal processing circuit 403, and interleaving processing, etc. Then, unnecessary high-frequency components are removed through a low-pass filter 404 suitable for the transmission rate of the digital code.

With this digitally encoded audio, the 90 degree phase shifter 215
The video signal carrier wave phase-shifted by 90 degrees is modulated by a converter 214 for PGM audio 1g signal, and added to the carrier wave modulated by the video signal by an adder 215. As a result, the video carrier wave must be modulated in an orthogonal relationship with the video signal and the PCM audio signal.

The modulated spectrum tgS diagram is shown in FIG. 6, and the vector diagram t of the modulation state of the video signal of the L1 video carrier wave and the PCM audio signal is shown in FIG. 7. 501 in FIG. 5 is the spectrum after the VSB:y filter of the video signal, and 502 is the spectrum after the VSB:y filter.
The spectrum of the modulated audio signal is shown at 601 in FIG. 6, which shows the spectrum of the digitized PCM audio signal. Here, the spectrum of the PCM audio signal shows the spectrum when the carrier wave of a signal with a transmission rate of IM bits/second and a roll-off rate of α5 is modulated.

In Figure 5, -0.75MHz for the video carrier.
The following spectrum is attenuated by a VSB filter with residual sideband amplitude modulation. 4.2M
Up to Hz, a video signal has a spectrum in the vicinity of 4.5 MHz where the audio carrier wave is FM modulated. Since both sidebands are transmitted for ±0.75 MHz with respect to the video carrier wave, it can be considered as general amplitude modulation (DSB). Orthogonal to the carrier wave having both sidebands, 7J', ±0.75Mf as shown in Fig. When modulated with , the carrier wave vector is a video signal?!
When set to -1.

Cog 111C1*A sin -Ct
It becomes 111. Here #C is the angular frequency of the carrier wave.

(Expanding equation 11, It is.

Let us now consider interference from a PCM audio signal to a received video signal. For those whose video signal detection circuit performs synchronous detection with C05set, Cog is applied regardless of the human value.
Only the #Ct coefficient (that is, only the video signal) is reproduced and does not cause interference. Also, for video signal detection circuits that perform envelope detection, interference can be reduced by lowering the human value by 1. For example, if Aiα1, ν<+X
- Medium 1005, and compared to 1, the a and 005 signals (approximately -40 dB) have an influence, but the 8N ratio of the Eirin signal is 40 d
If it is B or higher, there is no problem in practical use.

However, interference with the PCM audio detection circuit from the Eirin signal can be eliminated by demodulating only the portion orthogonal to the carrier wave in the synchronous detection circuit 119, as shown in FIG. Considering the signal level to noise ratio (hereinafter referred to as SN ratio),
Assuming that the S/N ratio of the video signal is at a practical level of 40 dB, the 8N ratio of the PCM audio signal is 46 dB because the bandwidth is approximately four times as large as the transmission bandwidth I MHz of the PCM audio signal.

If the modulation level of the PCM audio signal is Alα1, the 8N ratio will be about 26 dB.

-1 Even if we consider the relationship between the 8N ratio of the digital signal and the pit error rate using a general binary signal, the SN ratio is 17.4d.
B is 10. When the S/N ratio of the video signal is 40 dB, the S/N ratio of the PCM audio signal is 26 dB, which is a practically sufficient value for digital signal transmission.

Another embodiment of the invention is shown in FIG. The received signal 69 is the same as in FIG. 5, and the same reference numerals as in FIG. 5 indicate the same functions. 801 is a voltage controlled oscillation circuit, and 802 is a loop filter. In FIG. 8, the function of the carrier regeneration circuit 120 is constructed by a PI, L circuit using a voltage controlled oscillation circuit 801, a loop filter 802, and a synchronous detection circuit 119t. The phase of the output of the voltage controlled oscillation circuit 801 and the video carrier wave is detected using the synchronous detection circuit 119, taking advantage of the fact that the DC component of modulation by the PCM audio signal is small.

A loop filter 802 extracts a phase error signal.

This phase error signal is fed back to the voltage controlled oscillation circuit 801. The output of the voltage controlled oscillation circuit 801 is out of phase with the video carrier wave by 90 degrees and locked, and the output of the voltage controlled oscillation circuit 801 is in phase with the PCM audio carrier wave, so that the PCM audio can be demodulated by the synchronous detection circuit 119. can. In other words,
The synchronous detection circuit 119 operates with both a PCM audio demodulation function and a phase comparison function for carrier wave reproduction.

The embodiment shown in FIG. 8 has the advantage that carrier wave regeneration can be performed with a simple circuit configuration. Note that this operation and effect applies to the first local oscillation circuit 114 and the second local oscillation circuit 117.
This is an effect unrelated to t-control.

Another embodiment of the present invention is shown in Figure t-89. The received signal is the fifth
The same reference numerals as in FIG. 8 indicate the same functions.

The difference from FIG. 5 is that in FIG.
P that is reproduced by the carrier wave and modulated by being orthogonal to the video signal of the carrier wave.
Compared to the detection performed by the synchronous detection circuit 119 in synchronization with the CM audio signal, in FIG. Utilizing a small amount of money, the phase difference between the voltage controlled oscillation circuit 801 and the intermediate frequency signal including the carrier wave is detected by the synchronous detection circuit 119 and the loop filter 802, and! By feeding back to the second local oscillation circuit 117, the carrier wave of the second intermediate frequency f is synchronized with the output of the reference signal generator, and the output of the synchronous detection circuit 119 is used as the detected output.

The operation of the control circuit 124 is as follows.

+41 First local oscillation circuit 114 controls to change the first intermediate frequency f, "I&:.If the voltage controlled oscillation circuit 801 has a fixed frequency, the PLL is activated so that the second intermediate frequency etc. are constant. By controlling in this way, only the characteristics of the PCM band-pass filter 501 can be corrected, and interference from the video can be completely reduced.

(The output frequency of the local oversight circuit 114 of 51g- is fixed and the first intermediate frequency fI is constant. When the voltage controlled oscillation circuit 801 is controlled, the '1 voltage controlled oscillation circuit 801 output frequency and the second intermediate frequency are Feedback is applied to the second local oscillation circuit 117 so that the characteristics are the same.By controlling in this way, it is possible to correct only the characteristics of the band-pass filter 118, or to compensate for the performance limit or phase error of the synchronous detection circuit 119. It is possible to completely neutralize the interference from the video signal that occurs, and reduce the interference from the video signal.

(6) Is the output frequency of the second local oscillation circuit 117 controlled by controlling only the same frequency of the first local oscillation circuit 114 and the voltage controlled oscillation circuit 801fc? Fix it. By controlling in this way, the performance limit of the PCM bandpass filter 301, the second frequency conversion circuit 116, the bandpass filter 118, the synchronous detection circuit 119, etc. due to the 1,000 phase error that occurs from the video No. Interference can be neutralized and interference from video signals can be completely reduced.

By using the above (4), (5), and (6) in combination, interference from the video signal can be efficiently reduced.

According to this embodiment, since the negative feedback loop is such that the intermediate frequency for demodulation matches the frequency of the voltage controlled oscillator 801,
There is less demodulation frequency drift due to frequency drift of the first frequency conversion circuit 115, etc., and there is an effect that demodulation can be performed more stably than the embodiment shown in FIG.

Another embodiment of the invention is shown in FIG. The received signal is the third
This is the same as in the figure, and the same reference numerals as in figure 8g8 indicate the same functions. In FIG. 10, a phase difference between a voltage controlled oscillation circuit 801 and an intermediate frequency signal including a carrier wave is detected by a synchronous detection circuit 119 and a loop filter 802, and the first local oscillation circuit 1
14, the synchronous detection circuit 11 is synchronized with the output of the carrier all reference signal generator of the first intermediate frequency f1.
The reason is that the output of No. 9 is used as the detection output.

The operation of the control circuit 124 is as follows: (71 voltage controlled oscillation circuit 801 output is fixed frequency,
When the second local oscillation circuit 117 is controlled, feedback is applied to the 10th local oscillation circuit 114, and the first intermediate frequency f1 changes to become the second intermediate frequency f.

The PLL is locked so that the is the - foot. By controlling in this manner, only the characteristics of the PCM bandpass filter 501 can be corrected, and interference from the video line can be reduced.

(8: Second local oscillation circuit 117 and voltage controlled oscillation circuit 8
01 by the same frequency to control the first local oscillation circuit 11.
4 is fixed, and the first intermediate frequency fI is kept constant. By controlling in this way, it is possible to correct only the characteristics of the bandpass filter 118, or to neutralize interference from the video signal that occurs at the ninth stage of the performance limit or phase error of the synchronous detection circuit 119. Can reduce interference from signals.

(9) When the M2 local oscillation circuit 117 output is set to a fixed frequency and the 1-pressure control oscillation circuit 801 is controlled, feedback is applied to the first local oscillation circuit 114 and the first intermediate frequency f1%
The second intermediate frequency f changes. By controlling in this way, the PCM bandpass filter 301 and the second frequency conversion circuit.

116, band pass filter 118, synchronous detection circuit 119
It is possible to neutralize the interference from the video signal that occurs due to performance limitations and phase errors such as, and reduce the interference from the video signal.

The above +71, (8), and 191'f: By using them together, interference from the video signal can be efficiently reduced.

According to this embodiment, the first frequency conversion circuit 113 to the synchronous detection circuit 119 are included in the feedback harp.
This embodiment has the effect of more stable demodulation than the embodiment shown in FIG.

Another embodiment of the invention is shown in FIG. Components with the same symbols as in FIG. 5 indicate the same functions, 1101 is a frequency/wave number conversion circuit, 1102 is a local oscillation circuit, and 1103 is a band pass filter.

If the output frequency of the local oscillation circuit 1102 is fixed and the output frequency of the first local oscillation circuit 114 is controlled, the output frequency of the frequency conversion circuit 1101 will also change accordingly.
The second intermediate frequency fst" is kept constant.

That is, the operation is as explained in L111 in the i@3 diagram. Similarly, the output frequency of the first local oscillation circuit 114 is fixed.

If the output frequency of the first local oscillation circuit 1101 is controlled, the operation will be as shown in FIG.

According to this embodiment, there is an effect that the operations 111 and 121 in FIG. 3 can be realized by a simple control method.

Another embodiment of the invention is shown in FIG. Components with the same symbols as in FIG. 3 indicate the same functions, 1201 is a frequency conversion circuit, 1202 is a local oscillation circuit, and 1205 is a band pass filter.

If the local oscillation circuit 1202 and the second local oscillation circuit 117 are controlled, the operation shown in FIG. In the operation 2), if the output frequency of the second local oscillation circuit 117 is fixed and the local oscillation circuit 1202 is controlled, the operation will be as shown in FIG. 3 (3).

According to this embodiment, there is an effect that the operations shown in FIGS. 3(2) and 3(3) can be realized by a simple control method.

Another embodiment of the invention is shown in FIG. Components with the same symbols as in FIG. 9 indicate the same functions, 1301 is a frequency conversion circuit, 1302 is a local oscillation circuit, and 1503 is a band pass filter.

If the first local oscillation circuit 114 and the local oscillation circuit 1302 are controlled, FIG.
If the output frequency of the local oscillation circuit 1302 is fixed and the local oscillation circuit 1302 is controlled, the operation shown in FIG. becomes.

According to this embodiment, there is an effect that the operations shown in FIGS. 9(5) and 9(6) can be realized by a simple control method.

Another embodiment of the invention is shown in FIG. Components with the same symbols as in FIG. 9 indicate the same functions, 1401 is a frequency conversion circuit, 1402 is a local oscillation circuit, and 1405 is a band pass filter.

If the output frequency of the voltage controlled oscillation circuit 801 is fixed and the local oscillation circuit 1402 is controlled, the operation shown in FIG.
JIflS oscillation circuit 1402, voltage controlled oscillation circuit 80
If 1t-control is performed, the operation shown in FIG. 9 151, local oscillation circuit 1
The output frequency of 402 is fixed and the voltage controlled oscillation circuit 801t
- If controlled, the operation will be as shown in FIG. 9 (61).

According to this embodiment, the effects shown in FIGS. 9(4) and 9(6) can be realized by a simple control method.

Another embodiment of the invention is shown in FIG. Components with the same symbols as in FIG. 10 indicate the same functions, 1501 is a frequency conversion circuit, 1502 is a local oscillation circuit, and 1505 is a band pass filter.

If the second local oscillation circuit 117 and the local oscillation circuit 1502 are controlled, the operation shown in FIG.
Fixed output frequency of LIE 2 local oscillation circuit 117ft
If controlled, the operation of gIQ diagram (8:), the output frequency of the second local oscillation circuit 117 is fixed, and the local oscillation circuit 1502t-
If controlled, the operation will be as shown in FIG. 10 (91).

According to this embodiment, there is an effect that the operation shown in FIG. 10 (81%191) can be realized by a simple control method.

Another embodiment of the invention is shown in FIG. Items with the same symbols as in Figure 310 indicate the same functions 1. ．． 1601 is a frequency conversion circuit, 1602 is a local oscillation circuit, and 1605 is a band pass filter.

If the output frequency of the voltage controlled oscillation circuit 801 is fixed and the local oscillation circuit 16012j is controlled, the operation in FIG. 10 (71) is performed.

If the output frequency of the local oscillation circuit 1602 is fixed and the voltage controlled oscillation circuit is controlled, the operation shown in FIG.
The operation is as shown in Figure 191.

According to this embodiment, there is an effect that the operation shown in FIG. 10 (c) (8) can be realized by a simple control method.

Another embodiment of the invention is shown in FIG. The same reference numerals as in FIG. 8 indicate the same device 1?1, and 1701 is an adder circuit.

FIG. 17 shows the operation of the loop filter 802 in addition to the operation shown in FIG.
An adder circuit 1701 adds the signal from the control circuit 124 that received the interference detection signal to the nine-phase error signal extracted by the 9-phase error signal, and the added signal is fed back to the voltage-controlled oscillation circuit 801. In this case, the control response from the control circuit 124 is made sufficiently slower than the loop response determined by the loop filter 802.

In this embodiment, the output is the same as that of the voltage controlled oscillation circuit 801.

Since interference from the video signal caused by a phase error with the video signal carrier wave input to the phase detection circuit 119 can be reduced, it is possible to demodulate the PCM audio signal more accurately than in the example shown in FIG. effective.

Another embodiment of the present invention f: is shown in the 18th prisoner. The same symbols as in FIG. 17 indicate the same functions.

FIG. 18 is an example of FIG. 9 aimed at achieving the same effect as FIG. 17. This embodiment has the advantage of being able to fully demodulate the PCM audio signal more stably than the example of FIG. 9 for the same reason as in FIG.

Another embodiment of the invention is shown in Figure 19. The same symbols as in FIG. 17 indicate the same functions.

W, Fig. 19 combines all the effects similar to Fig. 17 with the example of Fig. 10. In this embodiment, for the same reason as in FIG. 17, there is an effect that the PCM audio signal can be demodulated more stably than in the example in FIG. 10.

Another embodiment of the invention is shown in FIG. FIG. 20 shows an embodiment that takes into account channel selection, etc. The same reference numerals as in FIG. 3 indicate the same functions, and 2001 is an automatic frequency control circuit (hereinafter abbreviated as AFC circuit).

2002 is a channel selection circuit, 2003, 2004, and 2005 are switch circuits, and 2006 is a nose circuit.

First, a desired channel is selected by the channel selection circuit 2002, and the first local oscillation circuit 114 is controlled through the switch circuit 2004 and the adder circuit 2006f. At this time, switch circuit 2003. '2005 is open. After the selection,
The switch circuit 2005'i is closed and the AFC circuit 2001 controls the output frequency of the first frequency conversion circuit 115 to become the first intermediate frequency. After the AFC operation is completed, the switch circuit 2005 f opens and the switch circuit 2005
'i close, perform an operation to reduce interference from the video signal to the PCM audio demodulated signal fx').

According to the non-embodiment, there is an effect that a simple circuit groove bottom can be used for channel selection, etc.

Another embodiment of the invention is shown in FIG. FIG. 21 also shows an embodiment that takes into account channel selection and the like. The same symbols as in FIG. 20 indicate all the same functions, 2101 is a video frequency conversion circuit, 21
02 is video local oscillation circuit, 2105.2104 is JJ
The O calculation circuit 2105.2106.2107 is a switch circuit.

A desired channel is selected by the channel selection circuit 2002, and the video system local oscillation circuit 2102 is selected through the switch circuit 2106.7, the JIII arithmetic circuit 2106, and the adder circuit 2104t.
and the first local oscillation circuit 114t. At this time, switch circuits 2105 and 2107 are open. After tuning, switch circuit 2105 t-close AFC circuit 200
1, the output frequency of the video frequency conversion circuit 2101 is controlled to be the video frequency intermediate frequency. - After tuning, close the switch circuit 2107 and input the PCM audio demodulated signal! Perform actions to reduce interference from the signal.

According to this embodiment, since the intermediate frequency is controlled to be optimal for each of the Eirin signal demodulation system and the PCM audio reproduction system, it is possible to achieve the best and most stable demodulation for both systems. .

Another embodiment of the present invention is shown in Figure t-122. Items with the same numbers as Prisoner 3 indicate the same functions. The difference from FIG. 3 is that the total interference detection circuit 123 performs interference detection from video based on the error rate detected from the error detection and correction code of the digitally encoded and transmitted audio/signal. This embodiment also has the effect that interference can be reduced as in FIG. 5, and that digitally encoded and transmitted audio signals can be stably demodulated.

Yet another embodiment of the invention is shown in FIG.

2301 is a synchronous detection circuit, 2302 is a phase shifter, 2505
2304 is a synchronization signal detection circuit, 2304 is a delay circuit, and the third
Items with the same symbols as in the figure indicate the same functions. The difference from FIG. 6 is that the synchronous detection circuit 2501 t uses a signal obtained by shifting the carrier wave obtained by the carrier wave regeneration circuit 120 by one phase by the phase shifter 2302.
The vertical or horizontal synchronizing signal of the video signal is detected by the synchronizing signal detection circuit 2305 from the detected output, and the vertical or horizontal synchronizing signal period of the video signal is detected by the delay circuit 2504. The control circuit 124 is controlled to conduct or sample the signal from the disturbance detection circuit 123, and to disconnect or hold the signal for other periods. The delay circuit 2304 is the interference detection circuit 1
23 and the synchronization signal detection circuit 2303 to absorb the difference in operation delay time.

The same applies if the output of the video signal detection circuit 105 can be used as the video signal detection output for synchronization detection.

The input of the signal detection circuit 2303 is the video signal detection circuit 10.
5, and the synchronous detection circuit 2601 and phase shifter 2302 may be omitted.

Note that interference from the video signal output from the synchronous detection circuit 119 is most likely to be detected during the horizontal synchronization signal period because the amplitude modulation of the video signal is greatest (because it does not change depending on the modulation of the synchronization signal period, the content of the status image, etc.) , interference from video signals can be detected stably.

According to this embodiment, since interference from a video signal can be detected stably, interference can be reduced more effectively.

This has the effect of stably demodulating digitally encoded and transmitted audio signals.

Another embodiment of the invention is shown in FIG. 125 is a disturbance detection circuit, 2401 is a subtracter, 2402 is a delay device (240
5 is @ switch, 2404 is time axis expansion circuit, 2405
2406 is a timing recovery circuit, and 2406 is a delay device.

2407 is an adder, and other components having the same symbols as in FIG. 3 indicate the same functions.

The demodulated waveform that is the output of the synchronous detection circuit 119 and the delay device 24
02 f: After that, a subtracter 2401 subtracts one horizontal period delay L7 from the demodulated waveform. By subtracting, the transmitted data is doubled and the white noise is only increased by -IT times.

Furthermore, interference from images that are highly correlated in each horizontal period, such as image ghosts, can be canceled out and removed. The signal obtained by the subtracter 2401 is converted into a digital code by the code identification circuit 302, and only necessary data from the digitally encoded signal is selected by the switch 2405' and the timing regeneration circuit 2405 and taken out by the time axis expansion circuit 2404. to return to the original data transmission rate.

-1, Demodulated waveform of output of synchronous detection circuit 119 and delay device 2
Add the demodulated waveform delayed by one horizontal period through 406 524
07, the transmitted friend data is canceled out and interference from the video signal can be effectively detected.

The output of the interference detection circuit 123 is transmitted to the control circuit 124,
Switch 2405 at the output of timing regeneration circuit 2405
Similarly, the transmitted data was offset.

The control circuit 124 is provided with a switch or a sample holding circuit function so that the signal is turned on or sampled during a certain period, and turned off or held during other periods.

Note that interference removal from the video signal by the subtracter 2401 is performed in the following process. If data X is sent at a certain timing in a certain horizontal scanning period, data X, which is the inverted version of the same data X, is sent at the same timing as a certain timing in the next horizontal scanning period with a delay of one horizontal period. The delay device 2402 and subtracter 2401 of the receiver cause 1
Since the receiver 72X received before the horizontal scanning period and the X received during the next horizontal scanning period are subtracted at the same timing, it becomes X-(also)-2X, and a signal twice as large is obtained. Assuming that there is G interference from the video signal during this transmission, if the image signal has a high correlation in each horizontal scanning period (an image with vertical stripes, etc.), G interference will occur at both the X timing and the X timing. You will receive it. The subtracter 2401 yields (X+())-(10G)-2X, and the interference from the video is canceled out. However, if the correlation between the horizontal scanning periods of the video signal is small, the canceling effect will be reduced.

These timings are shown using FIG. 29.

Furthermore, since the delay times of the delay device 2402 and the delay device 2406 are the same in one horizontal period, they may be used in common.

According to the embodiment described above, it is possible to further reduce interference from video signals, and it is possible to stably demodulate digitally encoded and transmitted audio signals.

Another example of a transmitter for generating the transmitted signal in the receiving embodiment described above is shown in FIG. 2501 is a processing circuit, and the same symbols as in FIG. 2 indicate the same functions. The processing circuit 2501 repeatedly performs processing for the adjacent L7 multiple times in each horizontal scanning period so that the data can be inverted and transmitted in reverse phase during the horizontal scanning period. Detailed explanation can be found in Section 26.27.
FIG. 26 shows a specific example of the processing circuit 2501 shown in FIG. 25, which is performed in FIG. 28 and the like. Further, FIG. 27 is a diagram for explaining operations such as an example of a transmission data string of the present invention, and FIG. 28 is an example of a simulated pattern of transmission data. 2601 is input shoji,
2602 is an inverter, 2603 is a delay circuit, 2604
is a timing generation circuit, 2605 is a changeover switch, 26
06 is an output terminal, 2701.2706 is a timing waveform within the timing generation circuit 2604, 2702 is an input data string, 2703 is an output data string of the delay circuit 2605,
2704 is an output timing waveform of the timing generation circuit 2604, and 2705 is an embodiment of the transmission data string of the present invention.

Data string 2702 applied to input terminal 2601, all inverters 2602, delay circuit 2603, and time τ
By delaying, a data string 27υ3 is obtained. Note that the timing waveform 2701 is inverted every time T.

The timing waveform 2704 is inverted during the data period in the data string, and when it is on the upper side in the figure, the changeover switch 2605 is in contact with the (I) side, and when it is on the lower side, it is in contact with the (B) side. By switching the changeover switch 2605, a data string 2705 is obtained on the output layer 2606.

Timing waveform 2706k Figure 428 is a diagram illustrating a data string 2705 ft as a horizontal synchronizing signal in accordance with the television screen. The horizontal scanning direction is shown horizontally, and the vertical scanning direction is shown vertically. As shown by the oval frame in Fig. 28, in the horizontal scanning period adjacent to IjIi, the top and bottom of each data are inverted. Inverting the data in adjacent horizontal scanning periods indicates that the multiplexed signals to the orthogonal components of the video carrier wave have an opposite phase relationship, and also has the effect of reducing interference with the hue change of the video due to the multiplexed signal. FIG. 29 shows the demodulation operation when receiving the transmission data string 2705t. 2901 is a timing waveform for synchronizing the horizontal scanning period, 2902 is a transmitted and received data string, and 2903 is a delay circuit 2402 and 2
406 output data string, 2904 output data string of subtracter 24o1, 2905 timing waveform, 290
6 is the output data string of the switch 2403, 2907 is the output data string of the time axis expansion circuit 2404, 2908 is the output data string of the adder 2407, and 2909 is the control circuit 124.
This is the data string after the switch operation in . The received data string 2902 is transferred to the delay circuit 2402 as a data string 2903.
become. When the data string 2902 is subtracted from the data string 29o3 by the subtracter 2401, a data string 2904 is obtained. Switch 2405 on the upper side of timing waveform 2905
If the t-connection is made, a data string 2906'i remains. The data string 2906 is converted into a data string 29 by the time axis expansion circuit 2404.
07, and the original data string 27 on the sending side shown in FIG.
Return to 02. Note that the data string 2906 and the data string 290
In 7, 2f, etc., are omitted to display double the received data string 2902 in the delay circuit 2406'f:
If it is too long, it becomes a data string 2903 in the same way. data column 290
2 and the data string 2905 by the adder 2407, a data string 2908 K- is obtained. When the data string 2908 is turned on within the control circuit 124 by performing a switch operation to conduct on the upper side of the timing waveform 2905 and discontinue on the lower side, an O and interruption are obtained as shown in the data string 2909. 0 indicates that the transmitted data has been canceled, and only interference from the video signal appears, indicating that interference detection is effective.

Also,! Timing waveform 290 inside IJ control circuit 124
If a sample holding operation is performed in which the upper side of 5 is sampled and the lower side is held, the previous o2 will be held at the interrupted point in the data string 2909.

As explained above, according to the embodiment shown in FIG. 24, the transmitted nine signals can reduce interference with the video signal, and the interference detection circuit can efficiently detect interference from the video signal.
4, it is possible to further reduce interference and stably demodulate digitally encoded and transmitted audio signals.

Another embodiment of the invention is shown in FIG. Components with the same symbols as in FIG. 3 indicate the same functions, and 3001 is a synchronous detection circuit;
3002 is a 90 degree phase shift circuit 1. 5003. 3004 is a band pass filter whose pass band can be varied, 5005 is a limiter circuit, 3006 is a 90 degree phase shift circuit, LO 3007 is a synchronous detection circuit, and 3008 is a low pass filter.

Interference detection circuit 124 t-@I from 3001 to 5008
! do. The signal regenerated by the carrier wave regeneration circuit 120 is rotated by 90 degrees.

The phase shift circuit 5002 shifts the phase by 90 degrees, and the synchronous detection circuit 300
1, the modulated signal is synchronously detected. The video signal is demodulated to the output of the synchronous detection circuit 3001, and at this time, interference from the video signal is output to the output of the synchronous detection circuit 119. From this synchronous detection 3001.119 output, we use a bandpass filter 3003.500 with a custom-made very narrow passband.
4 f and extracts a signal close to a single frequency. At this time, the passbands of the bandpass filters 3003 and 3004 are controlled to be exactly the same band by the control circuit 124. The output of the band pass filter 3003 is amplitude limited by a limiter circuit 3005 to have equal amplitude, and is phase shifted by 90 degrees by a 90 degree phase shift circuit 3006 to become a reference signal.

This reference signal and the output of the band pass filter 3004 are synchronously detected by the synchronous detection circuit 3007, and the low pass filter 1
Obtain the interference detection signal through 08 t-.

The above operation will be explained using mathematical formulas. The modulation signal E ideally extracted by the PCM bandpass filter 301 and the bandpass filter 118 is E-(1+A sin semi)sin *ct+P
Cog 5ect-sin sctAos(me-
yntAos(a+c+y)t+Pcos 5ect
111 Here, As1n jaw t is vibration 1iA, angular frequency -
m video signal, P is PCM audio signal, sin 5ect
is a video signal carrier wave, and cos sct is a PCM audio carrier wave. The modulation signal EZN actually input to the synchronous detection circuit 5001.119 is BIN-s in set + - (A, +)) cos (
sc-di n)t-pA*j)cos(*c+asthma)t+P
C01k "Ct (Decoding same order)...(Creates an amplitude difference between 2B and both side bands. (Formula 21 is EIH-(1+
As1n #r11t)sin #ct+(pshi)
cos #mt) cos a+ct
...<51, and the amplitude difference leaks into the orthogonal component.

The synchronous detection circuit 3001 outputs the video signal E! from BIN!・
Vj-1+ A s in act
・=-<41 Quadrature signal EQVq from WIN by synchronous detection circuit 119 ・P*i cos a+>t
...451 is demodulated. Now, if the PCM audio signal po is the video signal v! ,
Bandpass filter 30015004 from orthogonal signal vQ
Output V, n, vq, n ktSOFLSOtLvI%B
・To Asin...(6kv)
q, B・shi) cos town t...
-(71.Band pass filter 3003 output V1.
, ) Normalized by the elimitter circuit 5005, Iv summer, m l , , ·s in semi

...181 and the reference phase VV ・cos semi by the 90 degree phase shift circuit 3006
=...491 is obtained. Reference phase V
The band pass filter 3004 output Vq is synchronously detected by the ae synchronous detection circuit 3007, and the low pass filter 3008 output Vic t- is found to be V, - 4
...(10), the magnitude and polarity of the interference can be determined from the video signal, and the control circuit 124
You can request a return.

According to the non-embodiment, it is possible to find the polarity of the amplitude difference between both side bands, which is the cause of interference from the Eirin signal, and this? Using the first local oscillation circuit 114 and the second local oscillation circuit 1
Since we know the frequency control direction of 17, we can create a lock loop that minimizes the interference from the video signal! There are many effects that can be achieved.

Another embodiment of the invention is shown in FIG. ' Components with the same symbols as in FIG. 30 have the same functions, 3101 is a limiter circuit, and 5102 is a comparator circuit. .

The embodiment shown in Fig. 31 detects only the frequency control direction of the first and second local oscillator circuits 114 and 117 by using only the polarity of interference from the video signal determined by the equation shown in Fig. 30. The magnitude of the control is determined by the interference detection circuit 123. The interference detection circuit 123 is shown in FIGS. 22, 23, 24, etc.

The output vQ%B of the bandpass filter 3004 is set to IvQ, Bl by the limiter circuit 3101 ・±Cog #rr1t
...(11) It becomes a limit. Then, a polarity component is extracted using a synchronous detection circuit 3007 and a low-pass filter 3ooat-, and the polarity is determined by a comparator circuit 3102.

According to this embodiment, since the polarity and magnitude of the control signal can be determined by the respective optimum methods, there is an effect that stable control can be performed.

Another embodiment of the invention is shown in FIG. Is Figure 32 the same as Figure 24? Using the interference detection example in Figure 30 of IIK.

It is something that In FIG. 24, the same symbols as 2g5o@ indicate the same functions.

2908, which is the output of the adder 2407, is input to the bandpass filter 3004, and the lowpass filter 3
008 output using the control circuit 124.

All disturbances in the part where the data canceled out (part O in 2909) are detected.

According to this embodiment, even when PCM audio is multiplexed, interference can be detected and control is performed by the control circuit 124t, so there is an effect that efficient operation sound can be achieved.

Another embodiment of the invention is shown in FIG. Figure 35 shows 8g2
The interference detection example in FIG. 31 is used as a companion to the example in FIG. 4.

The same symbols as in FIGS. 24 and 31 indicate the same functions.

According to this embodiment, interference can be detected even when PCM audio is multiplexed, and the polarity and magnitude of the control signal can be determined using the optimal method, so there is an effect that all controls can be performed stably. .

Another embodiment of the present invention is shown in Figure tg54. ! i@50 The same reference numerals as in the diagram indicate the same functions, and 5401 is a variable bandpass filter whose frequency characteristics are completely variable.The variable bandpass filter 6401 is tracked by the control circuit 124 with the bandpass filters 6003 and 3004. Be variable. Low pass filter 3 which is the interference detection signal
008. The output is fed back to the variable bandpass filter 3401, and the tuning point t of the variable bandpass characteristic is varied to form a negative feedback loop that minimizes interference.

According to this embodiment, since the transmission path characteristics can be corrected so that interference is minimized for each frequency, leakage from the video signal to the orthogonal signal can be minimized at any frequency, and the PCM bandpass When a SAW filter whose performance is difficult to change after manufacture is used as the filter 301, the performance can be corrected, which has the effect of stably demodulating PCM audio.

Another embodiment of the invention is shown in FIG. The same symbols as in FIG. 34 indicate the same functions. FIG. 35 shows a bandpass filter 5401 t-controlled and a first local section.

It controls the oscillation circuit 114 or the second local oscillation circuit 117.

According to this embodiment, since the transmission path characteristics can be corrected so that the interference is the least at each frequency (t), the leakage from the video signal to the orthogonal component can be reduced to the maximum at any frequency, and the PCM bandpass When the filter 301 is a SAW filter whose performance is difficult to change after manufacture, it is possible to completely correct its performance, and it is also possible to correct deviations in the center frequency and shoulder characteristics, making it extremely stable. This has the advantage of being able to demodulate PCM audio.

Although not particularly mentioned in the explanations of the embodiments of the present invention shown in FIGS. 1, 3, 8 to 24, and 30 to 35 above, control for detecting and reducing interference is provided. The response of is assumed to be much slower than the demodulated wide response of the orthogonal multiplexed signal.

〔Effect of the invention〕

According to the present invention, it is possible to detect and efficiently reduce a signal that is multiplex transmitted and interferes with a ratio signal, so there is an effect that the multiplex transmitted signal can be stably reproduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a television receiver according to an embodiment of the present invention, FIG. 2 is a block diagram of a television receiver decoding generator, and FIG. 3 is a block diagram of a television receiver according to another embodiment of the present invention. 4 is a block diagram of another television signal generator, FIG. 5 is a spectrum diagram for explaining the present invention, and FIG. 6 is a spectrum diagram for explaining the present invention. FIG. 7 is a vector diagram for explaining the present invention, FIGS. 8 to 24 are block diagrams of a television signal receiver according to another embodiment of the present invention, and FIG. 25 is a diagram of another television signal generator. The block diagram of Figure 26 is! Figure 25 is a block diagram showing an example of the main part, Figure 27 is a waveform diagram of the transmission signal, and Figure 28 is a waveform diagram of the transmission signal.
29 is a waveform diagram of a transmission signal, and FIGS. 30 to 55 are block diagrams of television receivers according to other embodiments of the present invention. 113... First frequency conversion circuit, 114... First local oscillation circuit, 115... Extraction band pass filter, 116... Second frequency conversion circuit, 117... Second frequency conversion circuit. Local oscillation circuit, 118...Band pass filter, 1
23... Disturbance detection circuit, 124... Control circuit. Shoulder trip 5i^ Compiled with uJC

Claims (1)

[Claims] 1. A first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, A multiplex transmission signal that receives and reproduces a multiplexed signal that is synthesized and multiplexed with a second modulated wave signal obtained by modulating a second carrier wave that has a quadrature phase relationship with the first carrier wave. In the reproducing device, a first frequency conversion circuit that converts the received multiplexed signal into a first intermediate frequency signal, a first local oscillation circuit that determines the frequency of the output of the first frequency conversion circuit, and the a first bandpass filter that passes the transmission band of the second modulated wave signal of the first intermediate frequency signal; and a second bandpass filter that converts the output of the first bandpass filter into a second intermediate frequency signal. a second frequency conversion circuit, a second local oscillation circuit that determines the frequency of the output of the second frequency conversion circuit, and a transmission band of the second modulated wave signal of the second intermediate frequency signal; a second band-pass filter to pass through; a carrier-wave regeneration circuit for regenerating a reference carrier synchronized with a carrier included in the output of the second band-pass filter; and a carrier-wave regeneration circuit for regenerating the output of the second band-pass filter. a synchronous detection circuit that performs synchronous detection using the output from the synchronous detection circuit and outputs a demodulated signal of the second modulated wave signal; and a synchronous detection circuit that detects interference signal components other than the second modulated wave signal from the output of the synchronous detection circuit. a disturbance detection circuit, and a control circuit that controls the output frequency of the first local oscillation circuit or the second local oscillation circuit so that the disturbance signal component is reduced in accordance with the detection output from the disturbance detection circuit; A multiplex transmission signal reproducing device characterized by comprising: 2. A first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, which has a quadrature phase with the first carrier wave. In a multiplex transmission signal reproducing device that receives and reproduces a multiplexed signal transmitted by combining and multiplexing a second modulated wave signal obtained by modulating a related second carrier wave, the received a first frequency conversion circuit that converts a multiplexed signal into a first intermediate frequency signal; a first local oscillation circuit that determines the frequency of the output of the first frequency conversion circuit; a first bandpass filter that passes the transmission band of the second modulated wave signal; a second frequency conversion circuit that converts the output of the first bandpass filter into a second intermediate frequency signal; Said second
a second local oscillation circuit that determines the frequency of the output of the frequency conversion circuit;
a second bandpass filter that passes the transmission band of the modulated wave signal; a carrier regeneration circuit that regenerates a reference carrier synchronized with a carrier included in the output of the second bandpass filter; a synchronous detection circuit that synchronously detects the output of the pass filter with the output from the carrier regeneration circuit and outputs a demodulated signal of the second modulated wave signal; an interference detection circuit that detects an interference signal component other than the signal; and a control circuit that changes the transmission characteristic of the second bandpass filter so that the interference signal component is reduced in accordance with a detection output from the interference detection circuit. A multiplex transmission signal reproducing device comprising: 3. A first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, which is orthogonal to the first carrier wave. In a multiplex transmission signal reproducing device that receives and reproduces a multiplexed signal transmitted by combining and multiplexing a second modulated wave signal obtained by modulating a second carrier wave having a phase relationship, a received a first frequency conversion circuit that converts the multiplexed signal into a first intermediate frequency signal; a first local oscillation circuit that determines the frequency of the output of the first frequency conversion circuit; and the first intermediate frequency signal. a first bandpass filter that passes the transmission band of the second modulated wave signal; and a second frequency conversion circuit that converts the output of the first bandpass filter into a second intermediate frequency signal. , a second local oscillation circuit that determines the frequency of the output of the second frequency conversion circuit, and a second band that passes the transmission band of the second modulated wave signal of the second intermediate frequency signal. a pass filter, a carrier regeneration circuit that regenerates a reference carrier synchronized with a carrier included in the output of the second band pass filter, and synchronous detection of the output of the second band pass filter with the output from the carrier regeneration circuit. a synchronous detection circuit that outputs a demodulated signal of the second modulated wave signal; an interference detection circuit that detects an interference signal component other than the second modulated wave signal from the output of the synchronous detection circuit; controlling the output frequency of the first local oscillation circuit or the second local oscillation circuit so that the interference signal component is reduced in accordance with the detection output from the interference detection circuit; A multiplex transmission signal reproducing device comprising: a control circuit that changes transmission characteristics. 4. A first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, which is orthogonal to the first carrier wave. In a multiplex transmission signal reproducing device that receives and reproduces a multiplexed signal transmitted by combining and multiplexing a second modulated wave signal obtained by modulating a second carrier wave having a phase relationship, a received a bandpass filter that passes a transmission band of the second modulated wave signal among the multiplexed signals;
a synchronous detection circuit that synchronously detects the output of the bandpass filter using a reference carrier wave and outputs a demodulated signal of the second modulated wave signal; and an output of the reference carrier wave and the bandpass filter from the output of the synchronous detection circuit. a filter that extracts a phase error with a carrier wave included in the reference carrier wave; a variable frequency oscillation circuit that receives the output of the filter and generates the reference carrier wave;
A multiplex transmission signal reproducing device characterized by comprising: 5. The carrier regeneration circuit includes a filter that extracts a phase error between the reference carrier wave and a carrier included in the output of the bandpass filter from the output of the synchronous detection circuit, and a filter that generates the reference carrier wave in response to the output of the filter. Claims 1 and 2 are characterized in that the frequency variable oscillation circuit is constructed of a variable frequency oscillation circuit.
Alternatively, the multiplex transmission signal reproducing device according to any one of 3. 6. The second local oscillation circuit is replaced by a third local oscillation circuit, and a third frequency conversion circuit that receives the output of the first local oscillation circuit and the output of the third local oscillation circuit and determines the frequency. 6. The multiplex transmission signal reproducing apparatus according to claim 1, characterized in that it is comprised of: 7. A fourth frequency conversion circuit that receives the output of the second local oscillation circuit and the output of the fourth local oscillation circuit and determines the frequency of the first local oscillation circuit. 6. The multiplex transmission signal reproducing apparatus according to claim 1, characterized in that it is comprised of: 8. An adder circuit for adding the signal from the control circuit and the output of the filter is provided, and the output of the adder circuit is used as an input to the variable frequency oscillation circuit. The multiplex transmission signal reproducing device according to any one of the above. 9. A first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, which is orthogonal to the first carrier wave. In a multiplex transmission signal reproducing device that receives and reproduces a multiplexed signal transmitted by combining and multiplexing a second modulated wave signal obtained by modulating a second carrier wave having a phase relationship, a received a first frequency conversion circuit that converts the multiplexed signal into a first intermediate frequency signal; a first local oscillation circuit that determines the frequency of the output of the first frequency conversion circuit; and the first intermediate frequency signal. a first bandpass filter that passes the transmission band of the second modulated wave signal; and a second frequency conversion circuit that converts the output of the first bandpass filter into a second intermediate frequency signal. , a second local oscillation circuit that determines the frequency of the output of the second frequency conversion circuit, and a second band that passes the transmission band of the second modulated wave signal of the second intermediate frequency signal. a pass filter, a variable frequency oscillation circuit that reproduces a reference carrier wave synchronized with a carrier wave included in the output of the second band pass filter, and synchronously detects the output of the second band pass filter with the reference carrier wave. a synchronous detection circuit that outputs a demodulated signal of the second modulated wave signal; extracting a phase error between the reference carrier wave and a carrier wave included in the output of the bandpass filter from the output of the synchronous detection circuit; a filter that feeds back to the local oscillation circuit of the synchronous detection circuit; a disturbance detection circuit that detects a disturbance signal component other than the second modulated wave signal from the output of the synchronous detection circuit; A multiplex transmission signal reproducing device comprising: a control circuit that controls the output frequency of the first local oscillation circuit or the variable frequency oscillation circuit so that interference signal components are reduced. 10. The variable frequency oscillator circuit is comprised of a fifth local oscillation circuit and a fifth frequency conversion circuit that receives the output of the first local oscillation circuit and the output of the fifth local oscillation circuit and determines the frequency. 10. The multiplex transmission signal reproducing apparatus according to claim 9. 11. The first local oscillation circuit is replaced by a sixth local oscillation circuit and a sixth frequency conversion circuit that receives the output of the variable frequency oscillation circuit and the output of the sixth local oscillation circuit and determines the frequency. 10. The multiplex transmission signal reproducing apparatus according to claim 9. 12. Claim 9, characterized in that an adder circuit is provided for adding the signal from the control circuit and the output of the filter, and the output of the adder circuit is used as an input to a second local oscillation circuit.
12. The multiplex transmission signal reproducing device according to any one of 10 and 11. 13. A first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, which is in quadrature phase with the first carrier wave. In a multiplex transmission signal reproducing device that receives and reproduces a multiplexed signal transmitted by combining and multiplexing a second modulated wave signal obtained by modulating a related second carrier wave, the received a first frequency conversion circuit that converts a multiplexed signal into a first intermediate frequency signal; a first local oscillation circuit that determines the frequency of the output of the first frequency conversion circuit; a first bandpass filter that passes the transmission band of the second modulated wave signal; a second frequency conversion circuit that converts the output of the first bandpass filter into a second intermediate frequency signal; a second local oscillation circuit that determines the frequency of the output of the second frequency conversion circuit; and a second band pass that passes the transmission band of the second modulated wave signal of the second intermediate frequency signal. a frequency-variable oscillator circuit for regenerating a reference carrier wave synchronized with a carrier wave included in the output of the second band-pass filter; a synchronous detection circuit that outputs a demodulated signal of the second modulated wave signal; and a synchronous detection circuit that extracts a phase error between the reference carrier wave and a carrier included in the output of the bandpass filter from the output of the synchronous detection circuit and generates a first local oscillation signal. a filter that feeds back to the circuit, a disturbance detection circuit that detects a disturbance signal component other than the second modulated wave signal from the output of the synchronous detection circuit, and a disturbance detection circuit that detects the disturbance signal component according to the detection output from the disturbance detection circuit. a control circuit for controlling the output frequency of the variable frequency oscillation circuit or the second local oscillation circuit so that the frequency of the variable frequency oscillation circuit or the second local oscillation circuit is decreased. 14. The variable frequency oscillation circuit is configured by a seventh local oscillation circuit and a seventh frequency conversion circuit that receives the output of the second local oscillation circuit and the output of the seventh local oscillation circuit and determines the frequency. 14. The multiplex transmission signal reproducing apparatus according to claim 13. 15. The second local oscillation circuit is replaced by an eighth local oscillation circuit and an eighth frequency conversion circuit that receives the output of the variable frequency oscillation circuit and the output of the eighth local oscillation circuit and determines the frequency. 14. The multiplex transmission signal reproducing apparatus according to claim 13. 16. Claim 13, characterized in that an adder circuit is provided for adding the signal from the control circuit and the output of the filter, and the output of the adder circuit is used as an input to the first local oscillation circuit.
, 14 or 15. 17. Claims 1 and 3 or claims 5 to 16, characterized in that the control circuit is provided with an automatic frequency control circuit and an arithmetic control circuit that controls the output of the automatic frequency control circuit.
The multiplex transmission signal reproducing device according to any one of the above. 18. Claim 1, 3 or 3, characterized in that two systems of the first frequency conversion circuit and the first local oscillation circuit are provided for the first modulated signal and the second modulated signal. 17. The multiplex signal reproducing device according to any one of 5 to 16. 19. Claim 1, characterized in that the modulation signal other than the modulation signal for amplitude modulating the first carrier wave is digitally encoded signal data, and a digital demodulation circuit for demodulating the signal data is provided. 19. The multiplex signal reproducing device according to any one of 18 to 18. 20. The multiplexed signal reproducing apparatus according to any one of claims 1, 3, or 5 to 19, wherein the interference detection circuit is comprised of a level detection circuit that detects the signal amplitude of the input signal. 21. The multiplexed signal reproducing apparatus according to claim 19, wherein the interference detection circuit is constituted by an error detection circuit that detects an error rate of the demodulated multiplexed signal. 22. The interference detection circuit includes a delay circuit that delays an input signal for a certain period of time, an arithmetic circuit that performs arithmetic processing such as addition of the input signal and an output signal of the delay circuit, and detects the output signal amplitude of the arithmetic circuit. 20. The multiplex signal reproducing apparatus according to claim 19, further comprising a level detection circuit. 23. As the interference detection circuit, a 90 degree phase shift circuit that shifts the phase of the reference carrier wave by 90 degrees, and a second synchronization circuit that synchronously detects the output of the second band pass filter with the output of the 90 degree phase shift circuit. a detection circuit, a first extraction filter that extracts a single frequency component from the output of the second synchronous detection, an equal amplitude circuit that equalizes the amplitude of the output of the first extraction filter, and a phase shift of the output of the equal amplitude circuit by 90 degrees. a second 90 degree phase shift circuit, a second extraction filter for extracting a single frequency component from the output of the synchronous detection or the output of the arithmetic circuit; Claim 1 characterized in that a third synchronous detection circuit for synchronously detecting the extraction filter is provided.
23. The multiplex signal reproducing device according to any one of 3 or 5 to 19 or 22. 24. As the interference detection circuit, a 90 degree phase shift circuit that shifts the phase of the reference carrier wave by 90 degrees, and a second synchronization circuit that synchronously detects the output of the second band pass filter with the output of the 90 degree phase shift circuit. a detection circuit, a first extraction filter that extracts a single frequency component from the output of the second synchronous detection, an equal amplitude circuit that equalizes the amplitude of the output of the first extraction filter, and a phase shift of the output of the equal amplitude circuit by 90 degrees. a second 90 degree phase shift circuit, a second extraction filter that extracts a single frequency component from the output of the synchronous detection or the output of the arithmetic circuit, and a second extraction filter that equalizes the amplitude of the output of the second extraction filter. Equal amplitude circuit, said second
A third synchronous detection circuit that synchronously detects the output of the equal amplitude circuit and the output of the second 90 degree phase shift circuit, and a comparison circuit that divides the output of the third synchronous detection circuit into two states are provided. 23. The multiplex signal reproducing apparatus according to claim 20, wherein the multiplex signal reproducing apparatus is characterized in that: 25. Claims 1, 3, or 5, characterized in that the control circuit is provided with a disturbance signal control circuit that conducts or samples the signal from the disturbance signal, and controls the signal to be cut off or maintained during other periods. 25. The multiplex signal reproducing device according to 24. 26, a first modulated wave signal obtained by amplitude modulating the first carrier wave and a modulation signal other than the modulation signal that amplitude modulates the first carrier wave, which is orthogonal to the first carrier wave; In the multiplex transmission signal reproducing device that receives and reproduces a multiplexed signal transmitted by combining and multiplexing a second modulated wave signal obtained by modulating a second carrier wave having a phase relationship, A response of a control circuit that detects a disturbance signal component other than the second modulated wave signal from a demodulated signal of the second modulated wave signal, and controls the interference signal component so that the interference signal component decreases is detected from the demodulated signal of the second modulated wave signal. A multiplex transmission signal reproducing device characterized in that the response is slower than the response for obtaining a demodulated signal of a signal.