KR100274744B1 - Ntsc video signal receivers with reduced sensitivity to interference from co-channel television signal - Google Patents

Abstract

PURPOSE: NTSC TV signal receiver is provided to reduce sensitivity about an interference of a co-channel digital TV signal. CONSTITUTION: NTSC video receiver selects a vestigial sideband amplitude modulation signal indicating a video signal, converts the selected vestigial sideband amplitude signal to IF signal, and provides an amplified IF signal. A vestigial sideband amplitude modulation signal is selected by one of many channels including co-channel interference from a digital TV signal. The amplified IF signal is detected to a video carrier frequency, and generates a co-phase synchronous detection response signal and a quadrature phase synchronous detection response signal. All frequency components of the quadrature phase synchronous detection response signal is shifted by 90°, is linearly combined with a co-phase synchronous detection response signal, and restores a low frequency component of a suppressed video signal. A high frequency component of the video signal is selectively filtered to remove a signal component of a pilot carrier signal component of a co-channel digital TV signal, and is restored by synchronously detecting an amplitude modulation signal of a vestigial sideband. Artifacts of a pilot carrier signal are suppressed by a selective filtering. A full band video signal is obtained by combining a high frequency part and a low frequency part of a video signal.

Description

NTS video signal receiver with reduced sensitivity to interference from co-channel digital television signals

The present invention relates to NTSC television signal receivers, and more particularly to techniques for improving NTSC television signal receivers to be less susceptible to interference from co-channel digital television signals.

U.S. Patent No. 5,122,879, filed June 16, 1992, entitled " Television synchronous receiver with phase ahifter for reducing interference from a lower adjacent channel " for receiving analog television signals in-phase and quadrature. A video signal receiver of an analog television signal which is synchronously detected in phase) is described. In order to improve the noise figure by not using an amplifier of variable diode tuning, the receiver of this patent directly synchronizes the response of a high frequency (RF) amplifier to the baseband by directly synchrodyne. Allows the channel of the band to be represented by an image. The quadrature phase synchronous detection response is phase shifted by 90 degrees at all video frequencies above 750 kHz, and is linearly combined with the in-phase synchronous detection response and shifted to the baseband during phase detection of the video signal portion of the received NTSC signal. image frequency components). The patent does not describe the fact that this process removes video components above 750 kHz. However, loss of luminance of high frequency signals can be tolerated in small screen television receivers such as those used in wrist watches.

Modified band-limited video signal receiver of U.S. Patent No. 5,122,879 to shift the quadrature synchronous detection response by 90 degrees out of phase at all video frequencies, thereby limiting the artifacts of the co-channel interference digital television signal. Can be removed from the band NTSC signal. Orthogonal phase synchronous detection to ensure that the time constant of the automatic gain control circuit in the receiver is several horizontal scan lines and that the artificial noise of the co-channel digital television signal in the band-limited video signal does not appear on the television screen or interfere with horizontal synchronization. The response is supposed to be 90 degrees out of phase only for frequencies above a few kHz.

1,2,3,4,5,6,7 are capable of receiving NTSC analog television signals and digital television signals, and the method of the present invention for detecting the presence of co-channel interference NTSC analog television signals in digital television signals. A diagram showing a configuration diagram of a television receiver using

8 shows a preferred spectral response for the components of the television receivers of FIGS. 1,2,3,4,5;

9 is a block diagram of a synchine circuit that can be used in the television receivers of FIGS.

10 shows a preferred spectral response for the components of the television receiver of FIGS. 6 and 7.

A video signal receiver which is less sensitive to interference from co-channel digital television signals constructed in accordance with the present invention selects a vestigial sideband amplitude modulated signal representing the video signal and converts the selected residual sideband amplitude modulated signal into an intermediate frequency. And an input circuit for amplifying the intermediate frequency signal and providing the amplified intermediate frequency signal after conversion into a signal. The received residual sideband amplitude modulated signal includes a video carrier and a full sideband together with the residual sideband. The residual sideband amplitude modulated signal is selected from one of a plurality of channels, each of which sometimes includes co-channel interference from a digital television signal.

The video synchine circuit detects an amplified intermediate frequency signal with respect to the video carrier signal to generate an in-phase synchronous detection response and a quadrature phase synchronous detection response. All frequency components of the quadrature synchronous detection response signal above a predetermined frequency are 90-degree phase shifted by an inverse Hilbert transform and linearly combined with an appropriately delayed in-phase synchronous detection response signal to co-channel interfering digital television signals. The low frequency portion of the video signal represented by the front side band and the residual side band of the residual side band amplitude modulated signal suppressed by artificial artifacts is recovered. As used herein and in the claims, the term "linear combiner" means in general terms "addictive combiner" or adder, and "differential combiner" or subtractor.

According to another aspect of the present invention, the video signal receiver includes circuitry for recovering a high frequency portion of the video signal (which does not appear in the residual sideband) of the front sideband of the residual sideband amplitude modulated signal. The residual sideband amplitude modulated signal for high frequency component recovery of the video signal provided to this circuit is selectively filtered to remove the pilot carrier signal component of the co-channel digital television signal. This is to suppress the artificial noise of the pilot carrier signal generated when recovering the high frequency components of the video signal. The video signal receiver also linearly represents the high frequency components of the video signal as the front side bands and the residual side bands of the residual side band amplitude modulated signal, and the low frequency component of the video signal in which artificial artifacts from co-channel interference digital television signals are suppressed. It includes a circuit to combine.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 shows a television receiver capable of receiving not only digital television signals but also NTSC analog television signals. The wireless television broadcast signal received by the antenna 1 is amplified by an appropriately tuned high frequency (RF) amplifier 2 and applied to the first detector 3. The RF amplifier 2 and the first detector 3 work together as tuners for selecting the digital television signal from any one of the channels which are properly tuned and located in different frequency bands. The first detector 3 comprises a first local oscillator that provides a first local oscillation tunable over a frequency band above an ultra-high-frequency (UHF) television broadcast band and the first local oscillation. A UHF intermediate frequency signal of 6 MHz UHF intermediate frequency band located at a frequency above the assigned channel in the UHF television broadcasting band by up-converting by mixing with the television signal selected by the appropriately tuned RF amplifier 2 And a first mixer to produce.

The first detector 3 carries the UHF band intermediate frequency amplifier 4 for the NTSC audio signal, the UHF band intermediate frequency amplifier 5 for the fullband NTSC video signal, and the NTSC video high signal. In order to provide a high intermediate frequency signal to the UHF band intermediate frequency amplifier 6, respectively. The outputs of the UHF band intermediate frequency amplifiers 4, 5 and 6 are downconverted into VHF band intermediate frequency signals within a very high frequency (VHF) band below the high frequency allocated to the television broadcasting channel. The second detectors 7, 8, 9 share a common second local oscillator that generates a second local oscillation and output the second local oscillation signal and the UHF band intermediate frequency amplifiers 4, 5 and 6, respectively. And a second mixer for mixing the signals. The VHF band intermediate frequency signals from the second detectors 7, 8, 9 are respectively the VHF band intermediate frequency amplifier 10 for the NTSC audio signal, the VHF band intermediate frequency amplifier 11 and the NTSC for NTSC video signal. To the VHF band intermediate frequency amplifier 12 for the video high signal.

UHF band intermediate frequency amplifiers (4, 5, 6) are SAW (surface-acoustic-wave) for UHF intermediate frequency NTSC audio signal, UHF intermediate frequency NTSC video signal, and UHF intermediate frequency NTSC video high signal, respectively. ) Filters. SAW filters, which have steep rejection skirts but whose passbands have linear group delay and flat amplitude response, operate more easily in UHF than in VHF. Why is it more desirable to determine the overall mid-frequency response for UHF mid-band NTSC audio signals, UHF mid-band NTSC video signals, and UHF mid-band NTSC video high signals in the UHF mid-frequency band than in the VHF band? to be.

The SAW filter in the mid-frequency amplifier 5 for determining the overall mid-frequency response for the full-band NTSC video signal is the residual sideband amplitude modulated signal portion in the frequency range between 500 KHz and 6 MHz, at least 3.5 MHz above the lowest frequency of the television broadcast channel. By having a flat amplitude response, the residual sideband amplitude modulated signal is shifted to the UHF intermediate frequency band, suppressing the in-channel NTSC audio signal and the adjacent channel NTSC audio signal, and providing a linear phase response across the passband. It is desirable to have. The SAW filter in the intermediate frequency amplifier 5 suppresses the pilot carrier of the cochannel interference ATSC digital television signal while the linear phase response is maintained at 750 kHz from the NTSC video carrier frequency. The magnetic resonance of the intermediate frequency filtering for the full-band NTSC video signal induced by impulse noise is located near the middle of the intermediate frequency passband. Therefore, the ringing effect due to impulse noise is small, and if intermediate frequency filtering has at least 3MHz bandwidth, it can affect the baseband video response below 750kHz.

The SAW filter in the intermediate frequency amplifier 6 to determine the overall intermediate frequency response for NTSC video high signals suppresses the NTSC audio signal in the channel and the NTSC audio signal in the adjacent channel, and the 6MHz bandwidth television shifted to the UHF intermediate frequency band. It exhibits a roll-off characteristic with respect to 1.75 MHz of the lower side of the broadcast channel, and has a linear phase response characteristic over a pass band. The rolloff to 1.75 MHz on the lower side of the 6 MHz bandwidth television broadcast channel shifted to the intermediate frequency band suppresses the co-channel interference ATSC digital television signal and the NTSC video carrier in the channel. The SAW filter in the intermediate frequency amplifier 6 exhibits a roll-off characteristic for the upper side 550 kHz of the 6 MHz bandwidth television broadcast channel shifted to the UHF intermediate frequency band, and suppresses the in-channel sound signal.

Fig. 8 shows the preferred overall receiver responses for the low frequencies of the original transmission channel at the output of the UHF intermediate frequency amplifiers 5,6.

UHF band intermediate frequency amplifiers 4, 5 and 6 drive wideband constant-gain amplifiers to drive SAW filters from source impedance that minimize multiple reflections and to overcome the insertion loss of SAW filters. It may include. The VHF band intermediate frequency amplifiers 10, 11 and 12 each comprise a controlled gain amplifier providing 60 dB or more of amplification. The VHF band intermediate frequency amplifiers 10, 11, and 12 each have a forward automatic gain control stage obtained in response to the output signal level of the intermediate frequency amplifier 11, so that a forward AGC is preferable for a better noise figure. . The RF amplifier 2 has a delayed reverse automatic gain control in response to the output signal level of the intermediate frequency amplifier 11.

The response of the VHF intermediate frequency amplifier 10 is applied to the intercarrier sound detector 13, which provides an intercarrier sound intermediate frequency signal of 4.5 MHz to the intercarrier sound intermediate frequency amplifier 14. The intercarrier sound intermediate frequency amplifier 14 amplifies the intercarrier sound intermediate frequency signal and symmetrically limits the amplified signal for application to the FM detector 15. The FM detector 15 reproduces the baseband composite audio signal supplied to the sound reproducing section 16 of the NTSC receiver. The sound reproducing section 16 of the NTSC receiver includes a stereo sound decoder circuit. When the NTSC audio signal is selected by narrowband filtering in the intermediate frequency amplifiers 4 and 10 that pass only the FM audio carrier to the intermediate frequency, the intercarrier sound detector 13 outputs the output of the intermediate frequency amplifier 10. May be provided by a multiplier that multiplies the video carrier provided by the third local oscillator of the circuit 17 for synchronizing the full-band NTSC video signal to baseband.

Intercarrier when NTSC audio signal is selected and outputs "quasi-parallel" sound by filtering in the intermediate frequency amplifiers 4 and 10 that pass both NTSC video and audio carriers to intermediate frequency. The sound detector 13 may be a simple rectifier or a square-law device. Thereafter, the video carrier is no longer provided from the third local oscillator in circuit 17 for synchronizing the full band NTSC video signal to baseband.

The output signal of the VHF intermediate frequency amplifier 11 is applied to a circuit 17 for synchronizing the NTSC video carrier modulated signal to baseband, which may take the form as shown in FIG. In-phase synchronous detectors and quadrature synchronous detectors are used in the circuit 17 for synchronizing NTSC video carrier modulated signals to baseband. Synchro-dining is performed in the analog region within the circuit 17 for synchronizing the NTSC video carrier modulated signal to baseband, and the outputs of the in-phase synchronous detector 170 and the quadrature synchronous detector 171 used for this purpose are Digitized by analog-digital detectors 172 and 172, respectively. The third local oscillator 174 in the circuit 17 supplies the oscillation of phase 0 ^{0 to} the in-phase synchronous detector 170 and the oscillation of phase +90 ⁰ or -90 ⁰ through the phase shift network 175 at right angles. Provided to the phase-lock detector 171. The third local oscillator 174 is a controlled oscillator provided with an automatic frequency and phase control (AFPC) signal responsive to unwanted low frequency components appearing at the output of the quadrature synchronous detector 171. 9 shows that the outputs of the in-phase synchronous detector 170 and the quadrature synchronous detector 171 are filtered by the low pass filters 176 and 177, and the outputs of the low pass filters 176 and 177 are multiplied in the mixer 178. Multiplicavely mixed and the resulting signal is filtered using a low pass filter 179 to generate a typical Costas loop arrangement that generates an AFPC signal for the third local oscillator 174. Indicates an AFPC signal.

Synchronizing the NTSC video carrier modulated signal to the baseband may be performed in the digital domain after being converted into the final intermediate frequency band above the baseband to digitalize the final intermediate frequency. This solves the problem of two analog-digital converters 172 and 173 having different conversion gains.

The digital output signal Q of the quadrature synchronous detector 171 is a digital signal appearing at the output I of the Hilbert transform signal of the single sideband component of the NTSC signal (i.e., the component of frequency 750 kHz or more) and the in-phase synchronous detector 170. The artificial noise of the television signal is added together. Referring back to FIG. 1, the Hilbert transform signal provided by the output Q of the quadrature synchronous detector in the synchine circuit is phase shifted by an inverse Hilbert transform circuit 18 to provide a number of kHz or more. It provides a 90 degree lag at all frequencies. Suitable finite impulse response (FIR) filters for use with the inverse Hilbert transform circuit 18 are known in the field of digital television receivers.

The inverse Hilbert transform response signal of the circuit 18 is linearly combined with the digital response signal I of the in-phase sync detector in a linear combiner 19 to produce a luminance signal with a cutoff of 750 kHz. In this luminance signal, artificial noise is suppressed due to a single sideband characteristic called NTSC video carrier frequency of digital television artificial noise. The linear combiner 19 may be an adder or a subtractor depending on whether the operation of the quadrature synchronous detector is selected to lead or lag the operation of the in-phase synchronous detector.

The output signal of the VHF intermediate frequency amplifier 12 is applied to the quadrature phase synchronous detector 20. The quadrature phase synchronous detector synchronizes the NTSC video carrier modulated signal representing the high frequency portion of the composite video signal to the baseband. The quadrature phase detector 20 provides a digital response signal Q '. For example, when quadrature phase synchronous detection is performed in the analog domain, an analog-to-digital converter is cascaded to the next stage of the synchronous detector to digitize the response signal of the synchronous detector. The synchronization carrier for the quadrature phase detector is provided from a source (i.e., a phase shift network 175) in circuit 17 for synchronizing the NTSC video carrier modulated signal to baseband, which is synchronized to the synchine circuit 17. Synchronous carriers are also provided in quadrature phase synchronization detectors. The response signal Q 'of the quadrature phase synchronous detector 20 is a Hilbert transform signal of a single sideband component (i.e., components of 750 kHz or more) of the NTSC signal and a digital television signal passed through a SAW filter in the intermediate frequency amplifier 6. It is the sum of the artificial miscellaneous parts. The Hilbert transform signal provided by the response signal Q 'of the quadrature phase synchronous detector 20 is phase shifted by the inverse Hilbert transform circuit 21 to provide a lag of 90 degrees at a frequency of at least 500 kHz. This process produces the same response signal as the high frequency response signal of the in-phase NTSC video detector, but this response signal exhibits a low frequency cutoff complementary to the high frequency cutoff of the linear combiner 19.

The linear combiner 22 combines the output signals of the linear combiner 19 and the quadrature synchronous detector 20 to generate a fullband composite video signal to reproduce a picture on a screen. 23). This NTSC receiver section 23 generally includes a synchronous separation circuit and a color signal reproducing circuit. In NTSC and HDTV receivers, an NTSC image with a 4: 3 aspect ratio is displayed on a 16: 9 screen used for displaying a digital television image. It may be included to.

The inverse Hilbert transform circuit 18 requires a constant latency (or insertion delay) to provide a 90 degree lag for frequencies as low as several kHz. Providing a 90 degree lag for a frequency that is part of the horizontal scan ratio means that the uncontrolled artificial noise of the digital television signal has a frequency low enough for the AGC receiver to operate to suppress it. A shim delay is required to connect the I signal from the synchrodine circuit 17 to the linear combiner 19 so as to equalize the waiting time of the I signal and the Q signal supplied to the linear combiner 19. The rest delay unit must be cascaded with the inverse Hilbert transform circuit 21 such that its waiting time is shorter than that of the inverse Hilbert transform circuit 18. The inverse Hilbert transform circuit 21 can be made the same as the inverse Hilbert transform circuit 18 to eliminate the need for such a delay delay. When such a deformation is made, the separate Hilbert transform circuits 18 and 21 which are separated separately are not necessary, so that the circuit can be easily implemented.

FIG. 2 shows the configuration of a television receiver capable of receiving not only digital television signals but also NTSC analog television signals. The components 18-22 of FIG. An adder 24 coupling the output signal Q 'of the quadrature phase synchronous detector 20, an inverse Hilbert transform circuit 25 in response to a sum output signal from the adder 24, and an inverse Hilbert transform It is replaced by a linear combination circuit 26 that linearly combines the output signal of the circuit 25 and the output signal I of the synchine circuit 17 to produce a luminance signal that is cut off above 750 kHz. In the luminance signal, the digital television artificial noise is suppressed due to the single sideband characteristic of the artificial noise referred to as NTSC video carrier frequency. When the quadrature synchronous detector 20 and the quadrature synchronous detector in the synchine circuit 17 operate in different out-of-phase phases that are not in phase with each other, the adder 24 is replaced by a subtractor to perform the same operation. It can be done.

Synchronous detection of a video signal high frequency using a quadrature video carrier is advantageous when the crossover between the video signal low frequency and the video signal high frequency is automatically corrected. In addition, if a crossover occurs at the highest video frequency, digital television artificial noise is suppressed as high as possible.

3 is a variation of the television receiver of FIG. 1, which uses an in-phase synchronous detector 27 to synchronously detect a high frequency of a video signal instead of the quadrature synchronous detector 20, and in the television receiver of FIG. The synchronous detector 20, the inverse Hilbert transform circuit 21, and the linear combiner 22 are removed. Referring to FIG. 3, the crossover filter 28 low pass filters the output of the linear combiner 19 and high pass filters the output signal I 'of the in-phase synchronous detector 27, and then linearly combines them. It generates a full-band NTSC composite video signal and applies it to a predetermined portion 23 of the NTSC receiver used for reproducing the image on the screen. The crossover frequency at which lowpass filtering and highpass filtering are cut off in the crossover filter 28 is preferably at least 500 kHz. The television receiver of FIG. 2 is more economical than the receiver of FIG. 3 because it does not require the crossover filter.

1, 2 and 3, it is assumed that a color signal demodulation circuit of a television receiver is included in a predetermined portion 23 of an NTSC receiver used for reproducing an image on a screen. Is separated from the full-band composite video signal applied to a predetermined portion 23 of the NTSC receiver used to reproduce the picture. However, it is also possible to separate the color signal from the high frequency component of the composite video signal before combining it with the low frequency component of the composite video signal.

FIG. 4 shows a television receiver having a conventional color signal demodulation circuit 29 connected directly to the baseband video high frequency detected by the in-phase synchronous detector 27 as a variant of the television receiver of FIG. It is. The color signal demodulation circuit 29 is shown to be separated from the predetermined portion 30 of the NTSC receiver used to reproduce the image on the screen. The color signal demodulation circuit 29 provides a color difference signal to a predetermined portion 30 of the NTSC receiver. The full band composite video signal is applied to the portion 30 from the crossover filter 28.

FIG. 5 shows a television receiver having a conventional color signal demodulation circuit 29 connected directly to the baseband video high frequency detected by the quadrature synchronous detector 20 as a variant of the television receiver of FIG. It is. Since the color burst like other color signal components is phase shifted by 90 degrees, the fact that the Hilbert transform signal of the color signal is detected synchronously rather than the actual color signal does not affect the color difference signal recovery.

In the television receiver configuration of FIG. 6, the UHF band intermediate frequency amplifier 5 of the television receiver of FIG. 2 has a pass band for the entire frequency spectrum of the residual sideband amplitude modulated NTSC video carrier modulated signal. The NTSC video low frequency second detector 8 is replaced with a second detector 32 for the entire frequency spectrum of the residual sideband amplitude modulated NTSC video carrier modulated signal, and the VHF band intermediate frequency amplifier 11 remains. Sideband amplitude modulation is replaced by a VHF band intermediate frequency amplifier 33 having a passband for the entire frequency spectrum of the NTSC video carrier modulated signal. Figure 10 shows the preferred overall receiver response which is the low frequency of the original transmission channel at the output of the UHF intermediate frequency amplifier 33. According to this full bandwidth response, the UHF band intermediate frequency amplifier 6, the NTSC video high frequency second detector 9, the VHF band intermediate frequency amplifier 12, the NTSC video high frequency quadrature detector 20, and the inverse Hilbert transform circuit ( 21) all unnecessary. Instead, the high pass filter 34 extracts the video high frequency signal from the output signal of the inverse Hilbert transform circuit 18 and applies it to the linear combiner 22 so that it is linear with the video low frequency signal provided by the linear combiner 19. To be combined.

In the configuration of the television receiver of FIG. 7, the UHF band intermediate frequency amplifier 5 of the television receiver of the television receiver of FIG. 3 has a pass band with respect to the entire frequency spectrum of the residual sideband amplitude modulated NTSC video carrier modulated signal. Replaced by a frequency amplifier 31, the NTSC video low frequency second detector 8 is replaced by a second detector 32 for the entire frequency spectrum of the residual sideband amplitude modulation NTSC video carrier modulated signal, and a VHF band intermediate frequency amplifier. (11) is replaced by a VHF band intermediate frequency amplifier 33 having a passband for the entire frequency spectrum of the residual sideband amplitude modulated NTSC video carrier modulated signal. 10 shows the preferred overall receiver response, which is the low frequency of the original transmission channel at the output of the UHF intermediate frequency amplifier 33. According to this full bandwidth response, the UHF band intermediate frequency amplifier 6, the NTSC video high frequency second detector 9, the VHF band intermediate frequency amplifier 12, and the NTSC video high frequency in-phase detector 27 are all unnecessary. Instead, the output signal I of the in-phase sync detector in the synchine circuit 17 is applied to the crossover filter 28, which is provided at a video high frequency.

In the variants of the television receiver of FIG. 1, the color signal demodulation circuit can be arranged to respond directly to the output of the quadrature synchronous detector 20 or the inverse Hilbert transform circuit 21. In the variations of the television receiver of FIGS. 6 and 7, the color signal demodulation circuit is arranged to respond directly to the output signal I or the output signal Q of the synchine circuit 17 or to the inverse Hilbert transform circuit 18. Can be arranged to respond directly to the output of The arrangement of the above is also possible in the television receivers of FIGS. 1, 2 and 3 if the video low frequency intermediate frequency amplifier is modified to have an overall full band response as shown in FIG.

While the luminance signal exhibits strong line-to-line anticorrelation before it is modulated and after demodulation, it has strong line-to-line correlation. Because of the irregularity over the effect of co-channel digital signal on the color signal demodulation result, it can be reduced by the transversal filtering (like other irregular noise types). The NTSC receiver described above is incorporated into the digital television receiver described in the patent "Using video signals from auxiliary analog TV receivers for detecting NTSC interference in digital TV receivers" filed March 21, 1997, filed by the inventor. Can be. Modification of the above-described television receiver to use PAL or SECAM signals rather than NTSC signals can be easily performed by one of ordinary skill in the art of television receiver design. Although the NTSC television receiver for reproducing sound and image has been described above, the present invention can be applied to an NTSC television receiver mounted in an NTSC signal suppression filter for a videotape recorder or a digital television receiver which does not reproduce sound and image. .

Various modifications of the above-described receiver may be made by those skilled in the art of television receiver design, which should be considered in determining the claims.

Claims (20)

A channel of a plurality of channels, which represents a video signal and receives a residual sideband amplitude modulated signal comprising a video carrier wave and a front sideband with a residual sideband, at least one of which sometimes includes co-channel interference from a digital television signal. Selecting the residual sideband amplitude modulated signal from the second source signal, converting the selected residual sideband amplitude modulated signal into a first intermediate frequency signal, and amplifying the first intermediate frequency signal to provide an amplified first intermediate frequency signal; 1 input circuit; The amplified first intermediate frequency signal is synchronously detected with respect to the video carrier and the quadrature carrier of the video carrier signal to generate a first in-phase synchronous detection response signal, and generates a first quadrature phase synchronous detection response signal. A video synchine circuit for generating; A first phase shift circuit configured to generate a first phase shift circuit response signal by phase shifting all frequency components of the first quadrature phase synchronous detection response signal by a predetermined frequency or more by 90 degrees; And Linearly combining the first in-phase synchronous detection response signal and the first phase shift circuit response signal to represent the front band and the residual side band, and to suppress artificial noise from the same channel interference digital television signal. A video signal receiver having a reduced sensitivity to interference from co-channel digital television signals comprising a first linear combination circuit for recovering low frequency portions. The method of claim 1, The input circuit selects a residual sideband amplitude modulated signal representative of the video signal to suppress interference from co-channel digital television signals including a portion of the front sideband ranging from the video carrier to at least 1.75 MHz and the entirety of the residual sideband. A video signal receiver having a reduced sensitivity with respect to. The method of claim 2, Circuitry for recovering a high frequency portion of the video signal represented by the front side band but not the remaining side band; Further comprising a second linear combination circuit for recovering the video signal by linearly combining the low frequency portion of the video signal with the high frequency portion of the video signal, and having reduced sensitivity to interference from co-channel digital television signals. Video signal receiver. The method of claim 3, A circuit for recovering a high frequency portion of the video signal Selecting a portion of the front sideband of the residual sideband amplitude modulated signal, converting the selected portion into a second intermediate frequency signal, and amplifying the second intermediate frequency signal to provide an amplified second intermediate frequency signal; Two input circuits; A synchronous detector for generating a second quadrature phase synchronous detection response signal by synchronously detecting the amplified second intermediate frequency signal with respect to a quadrature carrier of the video carrier signal; And A second phase shift circuit for generating a second phase shift circuit response signal for recovering a high frequency portion of the video signal by phase shifting all frequency components of the second quadrature phase synchronous detection response signal above a predetermined frequency by 90 degrees; A video signal receiver having a reduced sensitivity to interference from channel digital television signals. The method of claim 2, Selecting a portion of the front sideband of the residual sideband amplitude modulated signal, converting the selected portion into a second intermediate frequency signal, and amplifying the second intermediate frequency signal to provide an amplified second intermediate frequency signal; Two input circuits; A synchronous detector for generating a second quadrature phase synchronous detection response signal by synchronously detecting the amplified second intermediate frequency signal with respect to a quadrature carrier of the video carrier signal; And An adder for adding the second quadrature phase synchronous detection response signal to the first quadrature phase synchronous detection response signal and applying it to the first phase shift circuit; The first phase shift circuit operates to generate the first phase shift circuit response signal by phase shifting all frequency components of the first and second quadrature phase synchronous detection response signals by a predetermined frequency or more by 90 degrees, and generating the first phase shift circuit response signal. A shift circuit response signal causes the first linear combination circuit to display the front side band, but not the residual side band, together with the low frequency portion of the video signal represented by the front side band and the residual side band of the video signal. A video signal receiver having a reduced sensitivity to interference from co-channel digital television signals for recovering high frequency portions. The method of claim 2, Selecting a portion of the front sideband of the residual sideband amplitude modulated signal, converting the selected portion into a second intermediate frequency signal, and amplifying the second intermediate frequency signal to provide an amplified second intermediate frequency signal; Two input circuits; A synchronous detector for detecting the amplified second intermediate frequency signal with respect to the video carrier signal to generate a second in-phase synchronous detection response signal for recovering the high frequency portion of the video signal; And And a crossover filter for recovering the video signal by combining the low frequency portion and the high frequency portion of the video signal with reduced sensitivity to interference from co-channel digital television signals. The method of claim 1, Circuitry for recovering a high frequency portion of the video signal represented by the front side band but not represented by the residual side band; And a second linear combination circuit for linearly combining the low and high frequency portions of the video signal to recover the video signal. The video signal receiver having reduced sensitivity to interference from co-channel digital television signals. The method of claim 7, wherein A circuit for recovering the high frequency portion of the video signal Selecting a portion of the front sideband of the residual sideband amplitude modulated signal, converting the selected portion into a second intermediate frequency signal, and amplifying the second intermediate frequency signal to provide an amplified second intermediate frequency signal; Two input circuits; A synchronous detector for generating a second quadrature phase synchronous detection response signal by synchronously detecting the amplified second intermediate frequency signal with respect to a quadrature carrier of the video carrier signal; And A second phase shift circuit for generating a second phase shift circuit response signal for recovering a high frequency portion of the video signal by phase shifting all frequency components of the second quadrature phase synchronous detection response signal above a predetermined frequency by 90 degrees; A video signal receiver having a reduced sensitivity to interference from channel digital television signals. The method of claim 1, Selecting a portion of the front sideband of the residual sideband amplitude modulated signal, converting the selected portion into a second intermediate frequency signal, and amplifying the second intermediate frequency signal to provide an amplified second intermediate frequency signal; Two input circuits; A synchronous detector for generating a second quadrature phase synchronous detection response signal by synchronously detecting the amplified second intermediate frequency signal with respect to a quadrature carrier of the video carrier signal; And An adder for adding the second quadrature phase synchronous detection response signal to the first quadrature phase synchronous detection response signal and applying it to the first phase shift circuit; The first phase shift circuit operates to generate the first phase shift circuit response signal by phase shifting all frequency components of the first and second quadrature phase synchronous detection response signals by a predetermined frequency or more by 90 degrees, and generating the first phase shift circuit response signal. A shift circuit response signal causes the first linear combination circuit to display the front side band, but not the residual side band, together with the low frequency portion of the video signal represented by the front side band and the residual side band of the video signal. A video signal receiver having a reduced sensitivity to interference from co-channel digital television signals for recovering high frequency portions. The method of claim 1, Selecting a portion of the front sideband of the residual sideband amplitude modulated signal, converting the selected portion into a second intermediate frequency signal, and amplifying the second intermediate frequency signal to provide an amplified second intermediate frequency signal; Two input circuits; A synchronous detector for detecting the amplified second intermediate frequency signal with respect to the video carrier signal to generate a second in-phase synchronous detection response signal for recovering the high frequency portion of the video signal; And And a crossover filter for recovering the video signal by combining the low frequency portion and the high frequency portion of the video signal with reduced sensitivity to interference from co-channel digital television signals. The method of claim 1, The input circuit selects the entire residual sideband amplitude modulated signal representing the video signal, but does not interfere with interference from co-channel digital television signals that suppress the accompanying carrier in-channel sound signal and the pilot carrier of the co-channel digital video signal. Video signal receiver with reduced sensitivity. The method of claim 11, A high pass filter for providing a high pass filter response to said first phase shift circuit response signal; And a second linear combination circuit for linearly combining the low frequency portion of the video signal and the high pass filter response signal for the second phase shift circuit response signal to recover the video signal. A video signal receiver having reduced sensitivity to interference from. The method of claim 11, And a crossover filter for recovering the video signal by combining the low frequency portion of the video signal with the high frequency portion of the video signal obtained from the first in-phase synchronous detection response signal. A video signal receiver having a reduced sensitivity with respect to. The method of claim 1, When the video signal receiver is a plural-conversion type, the first input circuit A first detector for selecting one of the plurality of channels and converting an NTSC signal in the channel into a UHF intermediate frequency signal; A frequency selective amplification is performed on a portion of the UHF intermediate frequency signal to generate a first amplifier response signal including signals remaining in response to the residual side band, the video carrier wave and at least a portion of the front side band representing the low frequency portion of the video signal. A first amplifier; And A second detector for converting the first amplifier response signal into a VHF intermediate frequency signal; Frequency selective amplification is performed on the VHF intermediate frequency signal to generate a second amplifier response signal provided to the video synchine circuit as an output signal of the first input circuit, wherein the residual sideband, the video carrier and the video signal are generated. A video signal receiver having a reduced sensitivity to interference from co-channel digital television signals comprising a second amplifier comprising signals responsive to at least a portion of the front band representing the low frequency portion of the signal. The method of claim 14, As components of the second input circuit comprising the first detector A third amplifier for performing a frequency selective amplification on a portion of the UHF intermediate frequency signal to generate a second amplifier response signal responsive only to a portion of the front band; Another second detector for converting the third amplifier response signal into a second VHF intermediate frequency signal; And And further comprising a fourth amplifier for performing frequency selective amplification on the VHF intermediate frequency signal to generate a fourth amplifier response signal provided as an output signal of the second input circuit and responsive to only a portion of the front side band. A video signal receiver having a reduced sensitivity to interference from signals. The method of claim 15, A synchronous detector for generating a second quadrature phase synchronous detection response signal by synchronously detecting the fourth amplifier response signal with respect to a carrier wave on the quadrature phase of the video carrier signal; A second phase shift circuit for generating a second phase shift circuit response signal for recovering a high frequency portion of the video signal by phase shifting all frequency components of the second quadrature phase synchronous detection response signal above a predetermined frequency by 90 degrees; And And a second linear combination circuit for linearly combining the low and high frequency portions of the video signal to recover the video signal. The video signal receiver having reduced sensitivity to interference from co-channel digital television signals. The method of claim 15, A synchronous detector for generating a second quadrature phase synchronous detection response signal by synchronously detecting the fourth amplifier response signal with respect to a carrier wave on the quadrature phase of the video carrier signal; An adder for adding the second quadrature phase synchronous detection response signal to the first quadrature phase synchronous detection response signal and applying it to the first phase shift circuit; The first phase shift circuit operates to generate the first phase shift circuit response signal by phase shifting all frequency components of the first and second quadrature phase synchronous detection response signals by a predetermined frequency or more by 90 degrees, and generating the first phase shift circuit response signal. A shift circuit response signal causes the first linear combination circuit to display the front side band, but not the residual side band, together with the low frequency portion of the video signal represented by the front side band and the residual side band of the video signal. A video signal receiver having a reduced sensitivity to interference from co-channel digital television signals for recovering high frequency portions. The method of claim 15, A synchronous detector for synchronously detecting the fourth amplifier response signal with respect to the video carrier signal and generating a second in-phase synchronous detection response signal for recovering a high frequency portion of the video signal; And a crossover filter for recovering the video signal by combining the low frequency portion and the high frequency portion of the video signal with reduced sensitivity to interference from co-channel digital television signals. The method of claim 14, A high pass filter providing a high pass filter response signal to the first phase shift circuit response signal; And a second linear combination circuit for linearly combining the low frequency portion of the video signal with the high pass filter response signal for the second phase shift circuit response signal to recover the video signal. A video signal receiver having reduced sensitivity to interference from. The method of claim 14, And a crossover filter for recovering the video signal by combining the low frequency portion of the video signal with the high frequency portion of the video signal taken from the second in-phase synchronous detection response signal. A video signal receiver having a reduced sensitivity with respect to.