JPS61129924A - Television braodcast receiver - Google Patents

Abstract

PURPOSE:To ensure excellent picture quality of a received picture by extracting a disturbing wave as an orthogonal phase synchronous detection output at double side band transmission band not including a video signal component so as to cancel and eject sufficiently the disturbing wave. CONSTITUTION:A carrier recovery circuit 8 recovers a carrier component from a carrier signal component of a modulation wave having double side band transmission component received together with a disturbing wave. The carrier component is phase-shifted by a pi/2 phase shift circuit 7 and the result is fed to a synchronous detection circuit 3. Further, the carrier signal component of the received modulation wave from the carrier component is subject to synchronous detection and the in-phase component is extracted by the 1st synchronous detection circuit 2. Similarly, the 2nd synchronous detection circuit 3 extracts the orthogonal phase component. Further, the orthogonal phase component is subject to pi/2 phase shift, the result is synthesized with the in-phase component at an adder circuit 5 to cancel and reject the disturbing wave mixed in the double side band transmission component.

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a television broadcast reception device that removes interference waves mixed in vestigial sideband television broadcast waves to achieve high-quality reception, and particularly relates to a television broadcast reception device that has a large influence on received image quality. This is useful because it allows interference waves mixed into both sideband transmission bands to be removed. Conventional technology Conventionally, in order to remove interference waves mixed in received television broadcast waves, a band rejection filter with a narrow rejection band width, that is, a so-called notch filter, is used to remove the signal components that are removed together with the interference waves. I tried to limit it. However, if the interference wave is within the both-sideband transmission band of the vestigial sideband television broadcast wave and is close to the video carrier wave, insertion of a notch filter will eliminate the secondary signal components. Since the waveform distortion of the demodulated output video signal appears large, even if the deterioration of the received image quality due to the generation of beats between the interference wave and the video carrier wave is reduced by inserting a notch filter, the image quality will deteriorate due to the secondary distortion of the signal waveform. This method has the disadvantage that sufficient improvement in received image quality cannot be obtained due to deterioration. SUMMARY OF THE INVENTION The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks and to demodulate the interference waves that mix into the both sideband transmission bands of vestigial sideband television broadcast waves and cause significant deterioration in the received image quality. without deteriorating image quality due to distortion of the output video signal waveform.
It is an object of the present invention to provide a television broadcast receiving device that can sufficiently remove broadcast signals. In other words, the television broadcast receiving apparatus of the present invention can detect interference waves of the television broadcast wave or an intermediate frequency signal obtained by converting the frequency of the television broadcast wave when interference waves are mixed in the both-sideband transmission band of the residual sideband transmission television broadcast wave. As a quadrature component of the demodulated output video frequency signal, the video signal component, which is a double sideband modulation component, does not appear, but the fact that only the next interference wave component mixed in the form of a single sideband modulation component appears. This system detects the interference wave component using the vestigial sideband method, and uses the detected output interference wave component to cancel out all of the interference wave components in the received television broadcast wave. or a carrier wave reproducing means for regenerating a carrier wave from an intermediate frequency signal obtained by converting the frequency of the television broadcast wave; First and second synchronous detection means each perform synchronous detection, and the frequency band of the output video signal of the second synchronous detection means is a frequency band corresponding to the double-side band transmission band of the television broadcast wave or intermediate frequency signal. A band limiting means for limiting the output video signal of the band limiting means to π/
a video frequency phase shifting means for shifting the phase by 2, and a combining means for combining the output video signals of the video frequency phase shifting means and the first synchronous detection means, and as an output of the combining means, the television broadcast wave Or the output video signal from which interference waves mixed in both sideband transmission bands of the intermediate frequency signal have been removed.
f: It is characterized by being made to obtain. EXAMPLES Below, the present invention will be described in detail by way of examples with reference to the drawings. First, the sideband distribution of the vestigial sideband television broadcast wave is shown in Figure 1 (al), which is similar to Figure 1 (b) and (
It can be divided into an in-phase component and a quadrature component, respectively shown in C). In the figure, ω. is the angular frequency of the video carrier wave. Now, the video signal in the television broadcast wave is expressed as G (t
), and the angular frequency sound ω of the image carrier wave. Then, amplitude modulated television broadcast wave G (t) cosω. tt - When vestigial sideband transmission is performed as shown in Figure 1 (al), the signal component can be expressed as follows.The following relationship is based on the frequency of the vestigial sideband transmission television broadcast wave. The same holds true for the converted intermediate frequency signal.
((tl t+θ)(1)oo
o. Here, θ is the video carrier angular frequency ω. where C(tl and S(t) respectively have custom transfer functions in which the video carrier angular frequency ω is shifted to O or zero frequency in FIGS. 1(bl and (C)). The above-mentioned amplitude modulated wave G(tl'i
These are the output responses obtained when each is supplied. Assume that the frequency band of the video signal G(tl is limited to the range ν shown in FIG. 1(a), the amplitude customization of the transfer function of the in-phase component is flat, and the phase customization is linear. , then C(tl = G(tl/2
becomes. Then, if the output expressed by equation (1) is synchronously detected using the carrier wave of equation (2) below, the original video signal can be completely demodulated. cos (ω is 10) (2) In-phase component amplitude 4? A custom-made band pass filter configured to flatten the band width is shown in FIG. 2(a), and the phase percentage of the filter is assumed to be linear. Therefore, the television broadcast wave t having the sideband distribution shown in FIG. 1(a) is supplied to the custom-made bandpass filter shown in FIG. Cos(ω.t+θ.), the original video signal is obtained by synchronous detection with a carrier wave having the same angular frequency ω. and phase θ. When synchronized detection is performed using a carrier wave Sin (ω.t+θ.) whose phase is different from the above-mentioned phase by θ., the video signal component is completely contained in the range of angular frequency θ to μ, and the video signal component is at right angles to the video signal component. Under such conditions, as shown in Fig. 2 (at), the interfering wave B@cos(Cω .+δ)tl(θ.+ψ〕)(δ) is mixed in.Here, (θ.+ψ) is the phase of the interference wave.This interference wave is set to the same angular frequency ω as the video carrier wave, and the phase θ., that is, the carrier wave expressed by equation (2), and the carrier wave 51n of the following equation (4), which has the same angular frequency ω as the video carrier wave but differs in phase by i (where ω is 100 ) (4) and IC to perform synchronous detection and extract only the baseband components, the in-phase g component B-008 (Jt + ψ) + O (tl quadrature phase component - -8in (at +IP) -3 (tl
(Two types of demodulated outputs of 61 are obtained. Among them,
When the quadrature component of equation (6) is added to a bandpass filter with a bandwidth μ, the first quadrature component of equation (6) is added to the output side of the filter.
, that is, the interference wave component B. Only -s1n (δt+ψ) (7) can be extracted. On the other hand, the in-phase component in equation (5) includes the original video signal component and the interference wave component even within the range of the bandwidth μ. Therefore, if we can create a signal component of the form -Co5(δt+ψ)(8) from the interference wave component expressed by equation (7), we can convert that signal component into the in-phase component of equation (5). By adding and combining the signals, the interference wave components can be canceled out and removed. Therefore, in order to create all the signal components of equation (8) from the interference wave component of equation (), the total phase of the interference wave component of equation (7) is 90
It is passed through an i phase shift circuit so that it is turned right angle by degrees or -. The receiving apparatus of the present invention is configured to realize the above-mentioned operating principle, and the basic configuration is shown in FIG. 3. In the configuration shown in the figure, the next television broadcast wave or an intermediate frequency signal whose full frequency has been converted by being supplied to the input terminal IO is guided to a bandpass filter 1 having good phase linearity, and the residual side band type television broadcast wave is Only the frequency band corresponding to the double-sideband transmission band is supplied to the synchronous detection circuits 2 and 8 in parallel after the signal amplitude is halved as shown in Fig. 2 (-). 2.3
The carrier wave for driving is obtained by supplying the television broadcast wave or intermediate frequency signal from the input terminal 10 to the carrier wave reproducing circuit 8 to extract the video carrier wave component, and converting the video carrier wave in the p-wave output of the bandpass filter. Generated in the same phase as the components. The in-phase carrier wave is directly applied to the synchronous detection circuit 2 to obtain the in-phase component video signal f, and -phase shift circuit 9
After shifting the phase by 90 degrees, the signal is applied to the synchronous detection circuit 3 and extracted as a quadrature phase component video signal and interference wave component total detection output. The detection output of the latter synchronous detection circuit 8 is supplied to a bandpass filter 6 that passes only the video frequency band corresponding to the double sideband transmission band of the vestigial sideband system television broadcast wave or intermediate frequency signal. From the output side of 6, extract only the intensity of the interference waves existing in the frequency band corresponding to the double-sideband transmission band, and use the interference waves to
If not, it is guided to the adder circuit 5 via a level adjustment circuit (not shown) t''.The video signal component from the former synchronous detection circuit 2 has a delay equivalent to that exhibited by the bandpass filter 6 in the other system. After aligning the timing through the delay circuit 4t, the signal is also guided to the adder circuit 5, and if it is added and synthesized with the above-mentioned interference wave component introduced from the other system, the signal is within the frequency band corresponding to the double-sideband transmission band. A high-quality demodulated output video signal in which mixed interference waves are canceled out and removed can be taken out from the output terminal 11.The phase of the detected output interference wave component is shifted by 90 degrees - phase shift circuit 9#: c, transfer function As such a filter, for example, a transversal filter constructed using a charge-coupled device 00D, which has already been commercialized, can be applied. When configuring the phase circuit 9, it is also possible to include a custom-made bandpass filter 6.In addition, it is also possible to include a custom-made bandpass filter 6 as shown in FIG. 2(a) for television broadcast waves or intermediate frequency signals. The filter can be easily constructed by using a surface acoustic wave element, for example.Next, in the basic configuration shown in FIG.
The above-mentioned transversal filter nato special circuit f!
FIG. 4 shows another example of the configuration of the receiving apparatus of the present invention in which the π/2 phase shift circuit 9 is simply constructed using conventional circuit elements without using a circuit. In the configuration example shown in FIG. 4, the circuit portion surrounded by a broken line frame is exactly the same as the circuit portion of the remaining circuit except for the π/2 phase shift circuit 9t in the basic configuration shown in FIG. That is, in the configuration example shown in FIG. 4, the π/2 phase shift circuit 9t-1 power 3111M1a, the bandpass filmet 1 synchronous detection circuit 16, and the level adjustment circuit 16 in the principle configuration shown in FIG. 3 are connected in sequence. Depending on the configuration, the nine baseband interference components obtained from the Pantohus filter 6 are guided to the multiplication circuit 13 and multiplied by the recovered carrier from the carrier recovery circuit 8, thereby once converting them into the form of carrier interference components. Then, by extracting only the upper sideband component using the bandpass filter 14 and synchronously detecting it by synchronous detection transmission, the phase is shifted by 90 degrees from the F-wave output interference component of the bandpass filter 60, and 9 interference components are extracted, and the level The signal is supplied to the adder circuit 5 via the adjustment circuit 16. Therefore, the F wave output of the bandpass filter 6 is the interference wave component of equation (7), and the interference wave component of equation (7) and the recovered carrier wave of equation (2) obtained from the carrier wave regeneration circuit 8 are combined. By multiplying, the carrier interference wave component of the following equation (9) is obtained. When the second term on the right side of equation (9), that is, the lower sideband component, is removed by the bandpass filter 14 and only the first term on the right side, that is, the upper sideband component is extracted, the F-wave output carrier interference wave component becomes: is obtained. When this door wave output carrier interference wave component is guided to the synchronous detection circuit 15 and synchronously detected by the quadrature phase carrier wave according to the equation (4) from "/2# phase in-phase f, the interference wave component expressed by the following equation (11) is obtained. -COS (δt+ψ) (11) The level adjustment circuit 1 adjusts the level of the interference wave component in equation (11).
6, and then add and synthesize with the in-phase component video signal from the synchronous detection circuit 2, the nest 1 in equation (5) is obtained.
The mixed interference wave component represented by the term is canceled out, and only the demodulated output video signal 0 (t) is obtained. In addition,
The multiplication circuit 13 that performs multiplication with the reproduced carrier wave is a type of modulator, and for example, a balanced modulator can be applied. Next, in addition to the fact that mixed interference wave components have been removed, the present invention is designed so that the same broadcast wave or intermediate frequency signal as the television broadcast wave or intermediate frequency signal supplied to the first input terminal appears at the output terminal. An example of the configuration of the inventive receiver is shown in FIG. That is, the main part of the configuration example shown in FIG. 5 is similar to the configuration example shown in FIGS. Similarly to the configuration example shown in FIGS. 4 to 4, an in-phase component demodulated output video signal 0 (t) is obtained from which the interference wave components mixed in the frequency band corresponding to the double-side band transmission band are removed. - 10,000, When the detection output of the synchronous detection circuit 3 is supplied to the bandpass filter 17 which has a pass band corresponding to the single sideband transmission band of the vestigial sideband system television broadcast wave, it corresponds to the double sideband transmission band. Quadrature component video signal S that does not contain interference wave components mixed in the frequency band
(tl is obtained. This is natural because the frequency band in which the above-mentioned interference wave component exists is band-blocked. In such a state, the in-phase component video signal 0(t) from the adder circuit 5 and the carrier wave reproduction The in-phase carrier wave of equation (2) from the circuit 8 is supplied to the multiplication circuit 20 and multiplied to form an in-phase carrier video signal component, and the quadrature component video signal -S (t )
is supplied to the multiplication circuit 21 through the level adjustment circuit 18 and the delay circuit 19t-, and the quadrature phase carrier wave of equation (4) is also supplied to the multiplication circuit 21 and multiplied, thereby forming a quadrature phase carrier video signal component. do. After that, when the in-phase and quadrature-phase carrier video signal components are added and combined by the adder circuit 22, the output terminal 23 receives the TV of the formula (1) that was supplied to the input terminal IO, except that the mixed interference waves have been removed. A carrier video signal wave that is exactly the same as the television broadcast wave can be obtained. Note that the multiplier circuit 13 and the bandpass filter 1 in the configuration example shown in FIG.
4. If a cascade connection circuit of the synchronous detection circuit 15 and the level adjustment circuit 16 is used as an alternative, the structure of the circuit device can be simplified and lowered without using any special circuit elements, similar to the structure example shown in FIG. can be realized. Effects As is clear from the above explanation, according to the present invention, residual sideband television broadcast waves entering a television broadcast receiving apparatus are mixed into both sideband transmission bands, significantly deteriorating the received image quality. Interfering waves can be sufficiently canceled out and removed to ensure high quality received images without custom-made deterioration such as signal waveform distortion due to secondary signal component deletion. Furthermore, according to the present invention, as is clear from its operating principle, it is possible to simultaneously remove a plurality of interference waves mixed in the double sideband transmission band, and to eliminate interference waves in the double sideband transmission band, upper sideband, lower sideband, etc. Interfering waves mixed into either wave band or both simultaneously can be similarly removed as long as the interfering waves are not symmetrical on the frequency axis with respect to the video carrier wave. In other words, as long as the interference waves do not coincidentally mix into symmetrical frequency positions in the upper and lower sidebands with respect to the Eirin carrier wave9, under any conditions, the interference waves mixed in the relevant band,
Both can be canceled out in the same way. Unfortunately, as in the configuration example shown in Figure 4, when a signal component over a wide frequency band is phase-shifted by t-90 degrees, it can be configured using only conventional circuit elements without using a complicated transversal filter. By performing a 90 degree phase shift on signal components over a wide band, interference waves can be sufficiently removed using a simple and inexpensive circuit device, and high-quality reception can be achieved. Note that in the configurations shown in FIGS. 8 to 4,
The same effect can be obtained even if the bandpass filter 1 at the input end has a baseband F wave characteristic as shown in FIG. 6, for example, and is inserted at the output end. Furthermore, in the configuration shown in Figure 5, the interference waves mixed in the both sideband transmission bands can be almost completely removed without the need for an F-wave% bandpass filter as shown in Figure 2 (al). Since a television broadcast wave signal or intermediate frequency signal that is otherwise exactly the same as the input can be obtained, it can be installed in front of an off-the-shelf interference device to easily remove interference waves from television broadcast reception.For example, when broadcasting If the device of the present invention having the configuration shown in Figure 5 is installed in front of the receiving device at the satellite station in the wave relay network, high-quality broadcast wave relay can be easily achieved. If the device is configured to be inserted into the intermediate frequency amplification stage of a normal television receiver, interference waves can be removed regardless of the channel selection in the television receiver. The types of interference waves that can be removed without deteriorating image quality even if they enter the double-sideband transmission band of broadcast waves cover an extremely wide range, regardless of the type of interference waves, such as amplitude modulated waves and frequency modulated waves. A remarkable effect of the present invention is that the present invention can also eliminate offset beat disturbances caused by inter-office frequency differential pressure, which tend to occur at the boundary between different service areas of television broadcasting. You can also get

[Brief explanation of the drawing]

Figures 1 (a), (b) and (C+ are custom curve diagrams showing the sideband distribution, in-phase component and quadrature component, respectively, of television broadcast waves; Figure 2 (al), (bl and (C) μ) A custom-made curve diagram showing the band-pass filter used in the device of the present invention, the mode of interfering waves in the in-phase component and the quadrature-phase component, respectively, and a block diagram showing the principle configuration of the television broadcast receiving device of the present invention in Fig. 3 , FIG. 4 is a block diagram showing an example of the configuration; FIG. 5 is a block diagram showing another configuration; FIG. 6 is a custom curve diagram showing an example of a custom-made baseband filter used in the inventive device. 1, 6, 14, 17... band pass filter,
2゜8.15...Synchronized detection circuit, 4.19...Delay circuit, 5.22...Addition circuit, 7.9...-phase shift circuit, 8...Carrier regeneration circuit, 10 ...Input terminal, 1
1, 28... Output terminal, 18, 20, 21...
- Multiplier circuit, 16, 18...level adjustment circuit. Patent Applicant Japan Broadcasting Corporation Kintei Figure 1 O Figure 2 Proceedings Amendment 1 May 30, 1980 1. 2゜ Commissioner of the Japan Patent Office Kazuo Wakasugi■, Indication of Case 1988 Special Patent Application No. 68985 2, Name of the invention: Interference wave elimination receiver (435) Japan Broadcasting Corporation 4, Agent system ρ (Amendment) Title of the invention: Interference wave elimination receiver 3.Detailed explanation of the invention Field: The present invention provides a vestigial sideband modulation television system that eliminates the interfering interference waves mixed into the transmission components. This relates to an interference wave removal receiving device that receives broadcast waves, etc., and is designed to be able to remove interference waves that have entered the double-side band transmission band, which has a large effect on received image quality. In order to remove interference waves that are mixed in with television broadcast waves, a band rejection filter with a narrow rejection band width, a so-called notch filter, is used to localize the signal components that are removed along with the interference waves. However, if the frequency of the interference wave is close to the video carrier frequency of the vestigial sideband modulation television broadcast wave, especially if it is within the double sideband transmission band of the television broadcast wave. In this case, the waveform distortion of the demodulated output video signal due to the deletion of signal components that occurs as a secondary result of inserting a notch filter appears, and the deterioration of the received image quality due to the occurrence of beats between the interference wave and the video carrier wave is caused by the notch filter. Even if the problem is alleviated by inserting a filter, the problem is that the image quality deteriorates due to the distortion of the signal waveform that occurs as a side effect, and the received image quality cannot be sufficiently improved. This method eliminates the above-mentioned conventional drawbacks and eliminates interference waves that mix into the double-sideband transmission band of received vestigial sideband modulation television broadcast waves and cause significant reception interference by distorting the waveform of the demodulated output signal. An object of the present invention is to provide a receiving device for eliminating interference waves that can sufficiently eliminate interference waves without deteriorating image quality due to residual sideband modulation. When interference waves enter the double-sideband transmission band of television broadcast waves, etc., the signal component transmitted in both sidebands appears as the quadrature phase component of the demodulated signal of the carrier signal component of the received modulated wave. First, only the signal components transmitted in the car sideband are transmitted, and the interference waves also appear in that, so the interference waves are extracted by skillfully taking advantage of the fact that the interference waves are extracted, and the interference waves are extracted.
This is designed to cancel out and remove the interference waves mixed in the carrier signal component of the received modulated wave, and reproduce the carrier wave component from the carrier signal component of the modulated wave that has both sideband transmission components received including the interference wave. a carrier wave reproducing means for regenerating the carrier wave; a transmission wave shifter for shifting the phase of the carrier wave component regenerated by the carrier wave reproducing means; and a carrier signal component of the received modulated wave by the carrier wave component regenerated by the carrier wave reproducing means. a first synchronous detection means for synchronously detecting and extracting an in-phase component; and a first synchronous detection means for synchronously detecting and extracting an in-phase component; a second synchronous detection means for extracting a quadrature phase component; a quadrature phase component phase shift means for shifting the phase of the quadrature component extracted by the second synchronous detection means; and an output of the quadrature phase component phase shift means. The present invention is characterized by comprising a combining means for combining the output of the first synchronous detection means and canceling and removing the interference wave mixed into the double-side band transmission components. EXAMPLES The present invention will be described in detail below with reference to the drawings. First, the sideband distribution of a television broadcast wave using vestigial sideband modulation is shown in Figure 1(a), which is shown in Figure 1(b).
and (c), respectively. In the figure, ω. is the angular frequency of the video carrier wave. Now, the video signal in the television broadcast wave is expressed as G(t)
and the angular frequency of the image carrier wave is ω. Then, the amplitude modulated television broadcast wave G (t) cos ω. t first
When vestigial sideband transmission is performed as shown in Figure (a),
The signal component can be expressed as follows. Note that the following relationship also applies to an intermediate frequency signal obtained by converting the frequency of a vestigial sideband modulation television broadcast wave. C(t) cos (ωot+θo)−5(t)sin
(ωot+θo) (1) Here, θ. is the video carrier angular frequency ω. is the phase of the signal at and C(t)
and 5(t) are shown in FIGS. 1(b) and (c), respectively.
) are the output responses obtained when the above video signal G (t) is supplied to a circuit having a transfer function with a characteristic in which the video carrier angular frequency ω0 is shifted to 0, that is, zero frequency. Assume that the frequency band of the video signal G(t) is limited to the range ν shown in Figure 1(a), that the amplitude characteristics of the transfer function of the in-phase component are flat, and that the phase characteristics are flat. If it is linear, then C
(t)=G(t)/2. Therefore, if the output expressed by equation (1) is synchronously detected using the carrier wave of equation (2) below, the original video signal can be completely demodulated. cos (ω, 1+θo) (2) The bandpass characteristics of a bandpass filter configured to flatten the amplitude characteristics of the in-phase component are shown in Figure 2(a), and the phase characteristics of the filter are Make it linear. Therefore, the television broadcast wave having the sideband distribution shown in Fig. 1(a) is
The filtered output is supplied to a bandpass filter with the band characteristics shown in , and the filtered output is set to the same angular frequency ω as that of the video transmission. and phase θ. When the synchronous detection is performed using the carrier wave COS (woj+θG) having
The video carrier has the same angular frequency ω, but the phase θ as mentioned above. When synchronized detection is performed using a carrier wave of 5 inches (ω.t+θ0) that differs by - with the time delay direction being positive, a quadrature component of the video signal component that does not contain any video signal component is obtained in the angular frequency range of 0 to μ. It will be done. Under such conditions, as shown in FIG. 2(a). The following interference wave A-cos ((ω.+δ)t+(θ.+ψ)) is generated at a frequency position separated by the angular frequency δ from the angular frequency ω0 of the video carrier wave.
Suppose that (3) is mixed in. Here, (θ0+ψ) is the phase of the interference wave. This interference wave has the same angular frequency ω as the video carrier wave. and a carrier wave with phase θ0, i.e., (
2) The carrier wave expressed by the formula and the same angular frequency ω as the video transmission wave. However, the following carrier wave 5in (ωot + θo) of equation (4) with a different phase only
(4) When synchronously detecting each and extracting only the baseband component, the in-phase component -cos (δt+ψ)+7°C(t)
(5) Quadrature component −'5in (δ = 1ψ) −−3(
Two types of demodulated outputs with t> can be obtained. Among them, (6)
When the quadrature component of the equation is added to a low-pass filter with a bandwidth μ, a component corresponding to the first term of equation (6) appears on the output side of the filter, that is, one interference wave component s+n(δt+ψ
)(7) Only can be taken out. On the other hand, the in-phase component in equation (5) includes the original video signal component and the interference wave component even within the range of the bandwidth μ. Therefore, if a signal component of the form 1-ycos(δt+ψ) (8) can be created from the interference wave component expressed by equation (7), then that signal component can be added and synthesized with the in-phase component of equation (5). By doing so, the interference wave components can be canceled out and removed. Therefore, in order to generate the signal component of equation (8) from the interference wave component of equation (7), the receiving device of the present invention must have the same amount of interference wave component of equation (7). An example of the basic configuration is shown in FIG. In the configuration shown in the figure, the television broadcast wave supplied to the input terminal IO or an intermediate frequency signal obtained by converting the frequency of the television broadcast wave is guided to a round pass filter with good phase linearity, and the television broadcast wave using the vestigial sideband modulation method is Only the frequency band corresponding to the double-sideband transmission band of Fig. 2(a)
After reducing the signal amplitude by half as shown in , the signal is supplied to the synchronous detection circuits 2 and 3 in parallel. The carrier wave that drives these synchronous detection circuits 2.3 supplies the television broadcast wave or intermediate frequency signal from the input terminal 1O to the carrier wave regeneration circuit 8, extracts the video carrier wave component, and outputs the filtered signal from the bandpass filter. It is generated in the same phase as the video carrier wave component. The in-phase carrier wave is applied directly to the synchronous detection circuit 2 to obtain a video signal of the in-phase component, and after being phase-shifted by 90 degrees via the three-shift and sum circuit 7, it is applied to the synchronous detection circuit 3 to obtain a quadrature phase component. The component video signal and interference wave component are extracted as detection output. The detection output of the latter synchronous detection circuit 3 is supplied to a low-pass filter that passes only the video frequency band corresponding to the double-sideband transmission band of the vestigial sideband modulation type television broadcast wave or intermediate frequency signal. From the output side of 6, only the interference wave components existing in the frequency band corresponding to the double-sideband transmission band are extracted, and the extracted interference wave components are guided to the -phase shift circuit 9 and phase shifted by 90 degrees, and then Addition circuit 5 via a level adjustment circuit (not shown) if necessary.
lead to. The video signal component from the former synchronous detection circuit 2 is
After aligning the timing through a delay circuit 4 that provides a delay equivalent to the delay exhibited by the low-pass filter 6 in the other system, the signal is also led to the adder circuit 5, and is added and synthesized with the above-mentioned interference wave component led from the other system. In this way, it is possible to extract from the output terminal 11 a high-quality demodulated output video signal in which interference waves mixed in the frequency band corresponding to the double-side band transmission band are canceled out. Note that the -phase shift circuit 9 that shifts the phase of the detected output interference wave component by 90 degrees can be realized by configuring a filter whose transfer function has an impulse response of y. A transversal filter constructed using a charge-coupled device CCD that has been developed can be applied. Furthermore, when configuring the -phase shift circuit 9, it is also possible to include the filtering characteristics of the low-pass filter 6. Note that a bandpass filter that imparts the characteristics shown in FIG. 2(a) to television broadcast waves or intermediate frequency signals can be easily constructed by using, for example, a surface acoustic wave element. Next, in the configuration example shown in the third figure, at G'), -phase shift'? Another configuration example of the receiving device of the present invention in which the phase shift circuit 9 is simply configured using conventional circuit elements without using special circuit elements such as the above-mentioned transversal filter in the circuit 9 is shown in the fourth example. As shown in the figure. In the configuration example shown in the fourth figure, the circuit portion shown surrounded by a broken line frame is exactly the same as the remaining circuit portion excluding the phase shift circuit 9 in the configuration example shown in the third figure. That is, in the configuration example shown in FIG. 4, the i phase shift circuit 9 in the configuration example shown in FIG. , the baseband interference wave component extracted from the low-pass filter 6 is guided to the multiplication circuit 13 and multiplied by the recovered carrier wave from the cliff transmission regeneration circuit 8 to once return it to the form of a carrier interference wave component, By extracting only the upper sideband component and guiding it to the synchronous detection circuit 15, and performing synchronous detection using the quadrature phase carrier wave from the i-phase shift circuit 7, 9 is extracted from the filtered output interference wave component of the low-pass filter 6.
The interference wave component phase-shifted by 0 degrees is extracted and supplied to the adder circuit 5. Therefore, the filtered output of the low-pass filter 6 is the interference wave component of equation (7), and when this interference wave component of equation (7) is multiplied by the recovered carrier wave of equation (2) obtained from the carrier wave regeneration circuit 8', , the carrier interference wave component of the following equation (9) is obtained. 1' 5in (δt +1), cos(ci), t
+ θo) = −Δsi ro ((ωO+δ) to 10(θ. −ψ )) Ning+! ! -81n (ω.-δ)t+(μ0-ψ))(
9) If we remove the second term on the right side of equation (9), that is, the lower sideband component, using the bandpass filter 4 and extract only the first term on the right side, that is, the upper sideband component, then ω.+δ) to ten(θ0+ψ
)) = −Dcas(δt +CP) ・5
in(ω, t+θO)-sin(δ+ψ)・C0
A filtered output carrier interference wave component of 5(ω.t 10,) (10) is obtained. This filtered output carrier interference wave component is guided to the synchronous detection circuit 15, and an interference wave component expressed as is obtained. - cos(δt+ψ) (+17 After adjusting the level of the interference wave component in equation (11) by four times and adding and combining it with the in-phase component video signal from the synchronous detection circuit 2, we get (
5) The mixed interference wave component represented by the first term of the equation is canceled out and only the second term -C(t) remains, meaning the demodulated output video signal G(t) in terms of content. There is. Note that the multiplication circuit 13 that performs multiplication with the reproduced carrier wave is a type of modulator, and for example, a balanced modulator can be applied. Next, in the present invention, a broadcast wave or intermediate frequency signal that is exactly the same as the television broadcast wave or intermediate frequency signal supplied to the input terminal appears at the output terminal, except that the mixed interference wave component is removed. An example of the configuration of the receiving device is shown in FIG. That is, the main part of the configuration example shown in FIG.
As in the configuration example shown in FIGS. 3 and 4, an in-phase component demodulated output video signal C(t) is obtained from which the interference wave components mixed in the frequency band corresponding to the double-side band transmission band are removed. On the other hand, when the detection output of the synchronous detection circuit 3 is supplied to a bandpass filter 16 having a pass band corresponding to the single sideband transmission band of a vestigial sideband modulation type television broadcast wave, this bandpass filter 16 Interfering wave components mixed in the frequency band corresponding to the waveband transmission band are removed, and only the quadrature component video signal -H5(t) is obtained, as seen from equation (6). In this state, the in-phase component video signal C(t) from the adder circuit 5 and the in-phase Hata transmission wave of equation (2) from the carrier wave regeneration circuit 8 are supplied to the multiplication circuit 19 and multiplied, thereby producing an in-phase carrier image. The quadrature component video signal from bandpass filter 16 -7s(t)
is supplied to the multiplication circuit 20 via the level adjustment circuit 17 and the delay circuit 19, and the quadrature phase carrier wave of equation (4) from the π i phase shift circuit 7 is supplied to the 1 multiplication circuit 20 and multiplied. forming a phase carrier video signal; After that, when these in-phase and quadrature-phase carrier video signal components are added and synthesized by the adder circuit 2, the output terminal 22 receives the TV of the formula (1) supplied to the input terminal 10, except that the mixed interference wave has been removed. A carrier video signal wave that is exactly the same as the television broadcast wave can be obtained. In addition, the detection output of the synchronous detection circuit 3 is passed through the Ropes filter 6.
If the cascade connection circuit of the multiplier circuit 13, bandpass filter 4, and synchronous detection circuit 15 in the configuration example shown in FIG. 4 is used instead as the phase shift circuit 9, the configuration example shown in FIG. Similarly, the configuration of the circuit device can be simplified and realized at low cost without using any special circuit elements. In the above explanation, it is assumed that interference waves are mixed in the upper sideband of the double-sideband transmission band of the vestigial sideband modulation television broadcast wave, and the circuit configuration is adapted to accommodate this. The device is capable of canceling out and removing interference waves in exactly the same way even when interference waves are mixed into the lower sideband. That is, in this case, in the circuit tIF& shown in FIGS. 3, 4, and 5, the adder circuit 5 is configured to subtract the output of the delay circuit 4 by one output of the phase shift circuit 9. Alternatively, in the circuit configuration shown in FIG. 4, the adder circuit 5 may be left as is, and the bandpass filter 14 may be changed to pass only the lower sideband component. Effects As is clear from the above explanation, according to the present invention, interference waves that are mixed into the both sideband transmission bands of residual sideband modulation television broadcast waves and significantly deteriorate the received image quality are removed from the video signal component. Since it is extracted as a quadrature phase synchronized detection output in a double-sideband transmission band that does not include interference waves, characteristic deterioration such as waveform distortion of the video signal due to the deletion of secondary video signal components may occur when canceling and removing interference waves. However, it is possible to sufficiently cancel out and remove the signals to ensure a high quality received image. In addition, as in the configuration example shown in Figure 4, when phase-shifting a signal component over a wide frequency band by 90 degrees, a complicated transversal filter is not used, and the configuration is performed using only conventional circuit elements. 9 of the signal components over a wide band
By performing a 0 degree phase shift, it is possible to sufficiently remove interference waves and perform high-quality reception using a circuit device with a simple and inexpensive configuration. In the configurations shown in FIGS. 3 and 4, the bandpass filter 1 at the input end is provided with baseband filtering characteristics as shown in FIG. 6, for example, and inserted at the output end to obtain the same effect. asked. Furthermore, in the configuration shown in FIG. 5, as shown in FIG.
Without the need for a band-pass filter with the filtering characteristics shown in Figure 3, it is possible to almost completely eliminate interference waves mixed into both sideband transmission bands, and to receive a television broadcast wave signal or intermediate frequency signal that is exactly the same as the input. 1, it can be installed in front of a ready-made receiver to easily remove interference waves from television broadcast reception. For example, if the apparatus of the present invention having the configuration shown in FIG. 5 is installed in front of a receiving device at a satellite station in a broadcast wave relay network, high-quality broadcast wave relay can be easily achieved. Further, if the device of the present invention having the configuration shown in Figure 5 is configured to be inserted into the intermediate frequency amplification stage of a normal receiver, interference waves can be removed regardless of the channel selection in the receiver. . Furthermore, according to the present invention, in view of its operating principle,
Regardless of whether the interfering interference wave is modulated or non-modulated, regardless of the modulation format, and not limited to television broadcast waves using vestigial sideband modulation method, modulated waves that have both sideband transmission components. The special effect is that all interference waves asymmetrically mixed with respect to the carrier wave can be sufficiently removed from the carrier signal component of the carrier signal, regardless of the number of interference waves mixed in or the frequency change of the interference waves.

[Brief explanation of the drawing]

Figures 1 (a), (b) and (C) are characteristic curve diagrams showing the sideband distribution, in-phase component and quadrature phase component of television broadcast waves, respectively. Figure 2 (a), (b) and ( c) is a characteristic curve diagram showing the band-pass filter characteristics used in the device of the present invention and the mode of interference wave mixing in the in-phase component and quadrature phase component, respectively; Fig. 3 is a block line showing an example of the configuration of the interference wave removal receiving device of the present invention; 4 is a block diagram showing another configuration example of the receiving device, FIG. 5 is a block diagram showing still another configuration example of the receiving device, and FIG. 6 is a base used in the device of the present invention. FIG. 3 is a characteristic curve diagram showing an example of characteristics of a band filter. 1, 14. 16...Band pass filter 2, 3
．． 15...Synchronous detection circuit 4.18...Delay circuit 5,21...Addition circuit 6...Low pass filter 7.9...i phase shift circuit 8...Carrier regeneration circuit 1o... input terminal 11,
22... Output terminal 13.19.20... Multiplier circuit 17... Level adjustment circuit. Procedural amendment September 5, 1980 L. 2゜1, Indication of the case 1982 Patent No. 68985 2 Name of the invention Interference wave removal receiving device Person making the amendment Relationship to the case Patent applicant (4 (5) Figures 1, 2, 3, 4, and 5 in the drawings of the Japan Broadcasting Corporation (corrected) Description Name of the invention Interference wave removal receiving device Claims include the above-mentioned double-sided waves Detailed description of the invention Field: The present invention provides residual sideband modulation by removing mixed interference waves from the band transmission components. The present invention relates to an interference wave removal receiving device for receiving standard television broadcast waves, etc., and is designed to be able to eliminate interference waves mixed in the double-sideband transmission band, which has a particularly large effect on received image quality. Conventionally, in order to remove interference waves mixed in received television broadcast waves, a band rejection filter with a narrow rejection band width, that is, a so-called notch filter, is used to localize the signal components that are removed along with the interference waves. However, if the frequency of the interference wave is close to the video carrier frequency of the vestigial sideband modulation television broadcast wave, it may be mixed within the double sideband transmission band of the television broadcast wave. When the notch filter is inserted, the waveform distortion of the demodulated output video signal due to the deletion of signal components that occurs as a side effect appears, and the deterioration of the received image quality due to the generation of beats between the interference wave and the video carrier wave is caused by the notch filter being inserted. Even if the problem is alleviated by inserting a filter, the problem is that the image quality deteriorates due to the distortion of the signal waveform that occurs as a side effect, and the received image quality cannot be sufficiently improved. The purpose is to eliminate the above-mentioned drawbacks of the conventional method and to eliminate interference waves that mix into the double-sideband transmission band of received vestigial sideband modulation television broadcast waves and cause significant reception interference by changing the waveform of the demodulated output signal. It is an object of the present invention to provide a receiving device for eliminating interference waves that can sufficiently remove interference waves without deterioration of image quality due to distortion. When an interference wave enters the double-sideband transmission band of a modulated television broadcast wave, etc., the signal component transmitted in both sidebands is the quadrature phase component of the demodulated signal of the carrier signal component of the received modulated wave. The interference wave is extracted by cleverly utilizing the fact that only the signal component is transmitted in a single sideband, and that the interference wave also appears, and the extracted interference wave is used to
This is designed to cancel out and remove the interference waves mixed in the carrier signal component of the received modulated wave, and reproduce the carrier wave component from the carrier signal component of the modulated wave that has both sideband transmission components received including the interference wave. a carrier wave regenerating means for regenerating the carrier wave, a carrier wave phase shifting means for shifting the phase of the carrier wave component regenerated by the carrier wave regenerating means, and a carrier signal component of the received modulated wave using the carrier wave component regenerated by the carrier wave regenerating means, and synchronously detecting the carrier signal component of the received modulated wave. a first synchronous detection means for extracting an in-phase component using the first synchronous detection means; a second synchronous detection means for extracting an eye component; a quadrature phase component phase shift means for shifting the phase of the quadrature component extracted by the second synchronous detection means by π/2; The apparatus is characterized by comprising a combining means for combining the output and the output of the first synchronous detection means to cancel out and remove the interference wave mixed into the double-side band transmission components. EXAMPLES The present invention will be described in detail below with reference to the drawings. First, the sideband distribution of a television broadcast wave using vestigial sideband modulation is shown in Figure 1(a), which is shown in Figure 1(b).
and (C), respectively. In the figure, ω0 is the angular frequency of the video carrier wave. Now, the video signal in the television broadcast wave is expressed as G(t)
If the angular frequency of the video carrier wave is ω0, then when the amplitude modulated television broadcast wave G (t) cos ω,1 is transmitted in the vestigial sideband as shown in Figure 1(a), the signal component is as follows. It can be expressed as Note that the following relationship also applies to an intermediate frequency signal obtained by converting the frequency of a vestigial sideband modulation television broadcast wave. C(t)cos(ωot+θo)−5(t)sin(
ω. t + θo) (1) Here, θ. is the video carrier angular frequency ω. is the phase of the signal at C(t
) and 5(t) are respectively shown in Figure 1(b) and (C
) of the video carrier angular frequency. These are the output responses obtained when the above-mentioned video signal G(t) is supplied to a circuit having a transfer function with a characteristic in which G(t) is shifted to 0, that is, zero frequency. Assume that the frequency band of the video signal G(t) is limited to the range ν shown in Figure 1(a), that the amplitude characteristics of the transfer function of the in-phase component are flat, and that the phase characteristics are flat. If it is linear, then C(
t)・G(t)/2. Therefore, if the output expressed by equation (1) is synchronously detected using the carrier wave of equation (2) below, the original video signal can be completely demodulated. cos (ω.t+θ.) (2) The bandpass characteristics of a bandpass filter configured to flatten the amplitude characteristics of the in-phase component are shown in Figure 2(a), and the phase characteristics of the filter are is linear. Therefore, a television broadcast wave with the sideband distribution shown in Figure 1(a) is supplied to a bandpass filter with the band characteristics shown in Figure 2(a), and its filtered output is the same as the video carrier wave. Angular frequency ω. and phase θ. The original video signal is obtained by synchronous detection with a carrier COS (ω.t+θ.), which has the same angular frequency ω as the video carrier. Even if the phase is θ as mentioned above,
When synchronized detection is performed using a carrier wave of 5 inches (ω. = 10.), which differs by i by setting the direction of time delay as positive, in the angular frequency range of 0 to μ, there is a quadrature of the video signal component that does not contain any video signal component at all. A phase component is obtained. Under such a state, as shown in FIG. 2(a), the angular frequency ω of the video carrier wave. The next interference wave A-CO8 ((ωG+δ)t+(θo+p)) is generated at a frequency position separated by the angular frequency δ from
Suppose that (3) is mixed in. Here, (θ
o+%) is the phase of the interference wave. This interference wave has the same angular frequency ω as the video carrier wave. and phase θ. , that is, the carrier wave expressed by equation (2), and the same angular frequency ω as the video carrier wave. However, the carrier wave 5in(ω, 1+
By performing synchronous detection using θ, > (4) and extracting only the baseband components, the in-phase component T C08 (δ + ρ) + T C (t)
(5) Quadrature component −T s+n(δt + 'f'
)--5(t), two types of demodulated outputs are obtained. When the quadrature component of equation (6) is added to a low-pass filter with a bandwidth μ, the output side of the filter becomes (6).
The component corresponding to the first term of the equation, that is, the interference wave component"
'2 Sl port (δt+P)
Only (7) can be taken out. On the other hand, the in-phase component in equation (5) includes the original video signal component and the interference wave component even within the range of the bandwidth μ. Therefore, if a signal component of the form 1-cos(δt+ρ) (8) can be created from the interference wave component expressed by equation (7), that signal component can be added and synthesized with the in-phase component of equation (5). By doing so, the interference wave components can be canceled out and removed. Therefore, in order to create the signal component of equation (8) from the interference wave component of equation (7), the phase of the interference wave component of equation (7) must be adjusted by 90
It is passed through a π phase shift circuit so that it is turned right angle by degrees, or -. The receiving apparatus of the present invention is configured to realize the above-mentioned operating principle, and an example of its basic configuration is shown in FIG. In the illustrated configuration, the television broadcast wave supplied to the input terminal 10 or an intermediate frequency signal obtained by converting the frequency of the television broadcast wave is guided to a bandpass filter having good phase linearity, and the television broadcast wave using the vestigial sideband modulation method is guided to a bandpass filter with good phase linearity. Only the frequency band corresponding to the double-sideband transmission band is shown in Figure 2 (a).
After reducing the signal amplitude by half as shown in >, the signal is supplied to the synchronous detection circuits 2 and 3 in parallel. The carrier wave that drives these synchronous detection circuits 2.3 supplies the television broadcast wave or intermediate frequency signal from the input terminal 1O to the carrier wave regeneration circuit 8, extracts the video carrier wave component, and outputs the filtered signal from the bandpass filter. It is generated in the same phase as the video carrier wave component. The in-phase carrier wave is directly applied to the synchronous detection circuit 2 to obtain a video signal of the in-phase component, and after being shifted by 90 degrees via the -shifting circuit 7, it is applied to the synchronous detection circuit 3 to obtain a video signal of the in-phase component. The phase component video signal and interference wave component are extracted as detection output. The detection output of the latter synchronous detection circuit 3 is supplied to a low-pass filter that passes only the video frequency band corresponding to the double-sideband transmission band of the vestigial sideband modulation type television broadcast wave or intermediate frequency signal. Only the interference wave components existing in the frequency band corresponding to the double-side band transmission band are extracted from the output side of the sun, and the extracted interference wave components are guided to the -phase shift circuit 9 and phase shifted by 90 degrees. Addition circuit 5 via a level adjustment circuit (not shown) if necessary.
lead to. The video signal component from the former synchronous detection circuit 2 is
After aligning the timing through a delay circuit 4 that provides a delay equivalent to the delay exhibited by the low-pass filter 6 in the other system, the signal is also led to the adder circuit 5, and is added and synthesized with the above-mentioned interference wave component led from the other system. In this way, it is possible to extract from the output terminal 11 a high-quality demodulated output video signal in which interference waves mixed in the frequency band corresponding to the double-side band transmission band are canceled out. In addition, the phase of the detected output interference wave component is shifted by 90 degrees. The phase shift circuit 9 can be realized by configuring a filter whose transfer function has a − impulse response, and such a filter can be configured using, for example, a charge-coupled device CCD that has already been put into practical use. A transversal filter etc. can be applied. Furthermore, when configuring the -phase shift circuit 9, it is also possible to include the filtering characteristics of the low-pass filter 6. Note that a bandpass filter that imparts the characteristics shown in FIG. 2(a) to television broadcast waves or intermediate frequency signals can be easily constructed by using, for example, a surface acoustic wave element. Next, in the configuration example shown in the third diagram, i shift (0 circuit 9
can be easily implemented using conventional circuit elements without using special circuit elements such as the transversal filter mentioned above.
FIG. 4 shows another example of the configuration of the receiving apparatus of the present invention in which the phase shift circuit 9 is configured. The circuit portion shown surrounded by a broken line frame in the configuration example shown in the fourth figure is completely the same as the remaining circuit portion excluding the π-phase shift circuit 9 in the configuration example shown in the third figure. That is, in the configuration example shown in FIG. 4, the -phase shift circuit 9 in the configuration example shown in FIG. The baseband interference wave component extracted from the low-pass filter 6 is guided to the multiplication circuit 13 and multiplied by the recovered carrier wave from the carrier wave regeneration circuit 8 to temporarily return it to the form of the carrier interference wave component. By extracting only the band component and guiding it to the synchronous detection circuit 15, and synchronously detecting it by quadrature wave transmission from the i-phase shift circuit 7, an interference wave component whose phase is shifted by 90 degrees from the filtered output interference wave component of the low-pass filter 6 is obtained. This is done so that the signal is taken out and supplied to the adder circuit 5. Therefore, the filtered output of the low-pass filter 6 is the interference wave component of equation (7), and when this interference wave component of equation (7) is multiplied by the recovered carrier wave of equation (2) obtained from the carrier wave regeneration circuit 8, The first general transmission interference wave component expressed by the following equation (9) is obtained. -! 5in (δ[10P)・C08(ω, 1+θ.)=
−−s+n((ωθ+δ)+(θ0−ρ))wound7~sin((ω.−δ)+(μ.−ρ))(
9) In Mushiko's equation (9), if the second term on the right side, that is, the lower sideband component, is removed by the bandpass filter 4 and only the first term on the right side, that is, the upper sideband component is taken out, then 1, s + n (( ω0+δ)t+(θo+H>)=--c
os (δt+%) 1 sin (ω, 1 + θ0) false one + s + n (δt 10 tp) ・ cos
(ω, t + θo) (10) The filtered output carrier interference wave component is eliminated. When this filtered output carrier interference wave component is guided to the synchronous detection circuit 15 and synchronously detected by the quadrature phase carrier wave from the π-phase shift circuit 7 according to equation (4), the interference wave component expressed by the following equation (11) is obtained. It will be done. -8. . 8(δt+(p)) (11) After adjusting the level of the interference wave component in equation (11) by four times and adding and combining it with the in-phase component video signal from the synchronous detection circuit 2, the The mixed interference wave component represented by the first term is canceled out and only the second term 1c(t) remains, meaning the demodulated output video signal G (t). Note that the reproduced carrier wave A multiplication circuit 13 that performs multiplication with
is a type of modulator, and for example, a balanced modulator can be applied. Next, in the present invention, a broadcast wave or intermediate frequency signal that is exactly the same as the television broadcast wave or intermediate frequency signal supplied to the input terminal appears at the output terminal, except that the mixed interference wave component is removed. An example of the configuration of the receiving device is shown in FIG. That is, the main part of the configuration example shown in FIG.
As in the configuration example shown in FIGS. 3 and 4, an in-phase component demodulated output video signal C(t) is obtained from which the interference wave components mixed in the frequency band corresponding to the double-side band transmission band are removed. On the other hand, when the detection output of the synchronous detection circuit 3 is supplied to a bandpass filter 6 having a pass band corresponding to the single sideband transmission band of a vestigial sideband modulation type television broadcast wave, this bandpass filter 6 Interfering wave components mixed in the frequency band corresponding to the waveband transmission band are removed, and only the quadrature component video signal 17s(t) is obtained, as seen from equation (6). In this state, the in-phase component video signal C(t) from the adder circuit 5 and the in-phase carrier wave of equation (2) from the carrier regeneration circuit 8 are supplied to the multiplication circuit 19 and multiplied, thereby producing the in-phase carrier video signal component. and the quadrature component video signal −yS(t) from the bandpass filter 16
is supplied to the multiplication circuit 20 via the level adjustment circuit 17 and the delay circuit 19, and the quadrature phase carrier wave of equation (4) from the π i phase shift circuit 7 is also supplied to the multiplication circuit 20 and multiplied. forming a phase carrier video signal; After that, when the in-phase and quadrature-phase carrier video signal components are added and synthesized by the adder circuit 2, the output terminal 22 receives the TV of the formula (1) that was supplied to the input terminal IO, except that the interfering interference waves were removed. A carrier video signal wave that is exactly the same as the television broadcast wave can be obtained. Note that the detection output of the synchronous detection circuit 3 is passed through a low-pass filter 6.
As the phase shift circuit 9, 'J! 4 Multiplying circuit 13 and bandpass filter 1 in the illustrated configuration example
4 and the synchronous detection circuit 15 as an alternative, the configuration of the circuit device can be simplified and realized at a low level without using any special circuit elements, similar to the configuration example shown in FIG. 4. be able to. In the above explanation, it is assumed that interference waves are mixed in the upper sideband of the double-sideband transmission band of the vestigial sideband modulation television broadcast wave, and the circuit configuration is designed to match this. The device of the present invention is capable of canceling out and removing interference waves in exactly the same way even when interference waves are mixed into the lower sideband. That is, in this case, in the circuit configurations shown in FIGS. 3, 4, and 5, the adder circuit 5 is replaced by the delay circuit 4.
It is only necessary to change the circuit to a subtraction circuit that subtracts the output of the -phase shift circuit 9 from the output of It may be changed so that only sideband components are passed. Effects As is clear from the above explanation, according to the present invention, interference waves that are mixed into the both sideband transmission bands of residual sideband modulation television broadcast waves and significantly deteriorate the received image quality are removed from the video signal component. Since it is extracted as a quadrature phase synchronized detection output in a double-sideband transmission band that does not include interference waves, characteristic deterioration such as waveform distortion of the video signal due to the deletion of secondary video signal components may occur when canceling and removing interference waves. However, it is possible to sufficiently cancel out and remove the signals to ensure a high quality received image. In addition, as in the configuration example shown in Figure 4, when phase-shifting a signal component over a wide frequency band by 90 degrees, a complicated transversal filter is not used, and the configuration is performed using only conventional circuit elements. 9 of the signal components over a wide band
By performing a 0 degree phase shift, it is possible to sufficiently remove interference waves and perform high-quality reception using a circuit device with a simple and low-level configuration. In the configurations shown in FIGS. 3 and 4, the bandpass filter l at the input end can be inserted at the output end with baseband filtering characteristics as shown in FIG. 6, for example, to obtain the same effect. It will be done. Furthermore, in the configuration shown in FIG. 5, as shown in FIG.
This method eliminates the need for a band-pass filter with the filtering characteristics shown in Figure 2, and almost completely eliminates interference waves mixed into both sideband transmission bands. Therefore, it is possible to easily remove interference waves from television broadcast reception by installing it in a ready-made receiving device. For example, if the apparatus of the present invention having the configuration shown in FIG. 5 is installed in front of a receiving device at a satellite station in a broadcast wave relay network, high-quality broadcast wave relay can be easily achieved. Further, if the device of the present invention having the configuration shown in Figure 5 is configured to be inserted into the intermediate frequency amplification stage of a normal receiver, interference waves can be removed regardless of the channel selection in the receiver. . Furthermore, according to the present invention, in view of its operating principle,
Regardless of whether the interfering interference wave is modulated or non-modulated, regardless of the modulation format, and not limited to television broadcast waves using vestigial sideband modulation method, modulated waves that have both sideband transmission components. A special effect can be obtained in that all interference waves asymmetrically mixed with the carrier signal component of the carrier wave can be sufficiently removed regardless of the number of interference waves mixed in or the frequency change of the interference waves. 4. Brief explanation of the drawings Figures 1 (a), (b) and (C) are characteristic curve diagrams showing the sideband distribution of television broadcast waves, the in-phase component right and the quadrature component, respectively; Figure 2 ( a), (b) and (c) are characteristic curve diagrams respectively showing the bandpass filter characteristics used in the device of the present invention and the mode of interference wave mixing in the in-phase component and the quadrature phase component. FIG. 4 is a block diagram showing an example of the configuration of the device; FIG. 5 is a block diagram showing another example of the configuration of the receiving device; FIG. 6 is a characteristic curve diagram showing an example of the characteristics of the baseband filter used in the device of the present invention. 1, 14. 16...Band pass filter 2, 3
．． 15... Synchronous detection circuit 4.18... Delay circuit 5.21... Addition circuit 6... Low pass filter 7, 9... - Phase shift circuit m
8...Carrier regeneration circuit 10...Input terminal 11,
22... Output terminal 13.19.20... Multiplier circuit 17... Level adjustment circuit. Figure 1 "r 1lEI'ゝαノO Figure 2 Figure 3 (NT, E) Figure 4

Claims (1)

[Claims] 1. Carrier wave reproducing means for reproducing a carrier wave from a vestigial sideband type television broadcast wave or an intermediate frequency signal obtained by converting the frequency of the television broadcast wave, and a carrier wave phase shifting means for shifting the phase of the reproduced carrier wave by π/2. and first and second synchronous detection means for synchronously detecting the television broadcast wave or intermediate frequency signal using the reproduced carrier wave and the π/2 phase-shifted carrier wave, respectively, and an output of the second synchronous detection means. Band limiting means for limiting the frequency band of the video signal to a frequency band corresponding to the double sideband transmission band of the television broadcast wave or intermediate frequency signal; and a video signal for shifting the phase of the output video signal of the band limiting means by π/2. It comprises a frequency phase shifting means and a synthesizing means for synthesizing the output video signals of the video frequency phase shifting means and the first synchronous detection means, and the output of the synthesizing means is the television broadcast wave or the intermediate frequency signal. A television broadcast receiving device characterized in that it obtains an output video signal from which interference waves mixed in both sideband transmission bands are removed.