JP2001313847A - Television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent malfunction of synchronizing separation with respect to a video signal subjected to ghost elimination using a transversal filter. SOLUTION: The television receiver is provided with a distortion correct circuit 121 that corrects the level of a vertical synchronizing signal of a video signal subjected to ghost elimination processing with the transversal filter 108 and with a clip circuit 109, that clips the pedestal level of the video signal at a reference pedestal level decided by a microcomputer 120, so as to prevent the malfunction of synchronizing separation processing of a synchronizing separator circuit 125.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver having a transversal filter for removing or reducing a ghost component superimposed on a television signal, and more particularly to a television receiver having a ghost removal process performed by a transversal filter. The present invention relates to a television receiver provided with an improvement for preferably separating a synchronization signal from a video signal.

[0002]

2. Description of the Related Art When receiving a television signal transmitted from a broadcasting station, distortion of a transmission line caused by superimposition of a reflected wave by an obstacle such as a high-rise building or a mountain on a direct wave is called a ghost. This is the largest cause of image quality degradation in terrestrial television broadcasting. Techniques for improving the image quality deterioration due to the ghost include, for example, the technical report of the Institute of Television Engineers of Japan, Vol. 13, NO. 32 (1
(June 986), pages 1 to 36.
This is a GCR (Ghost Cancel Reference) which is a reference signal for ghost removal on the broadcast station side.
The signal is inserted into a blanking period of a television signal and transmitted, and the ghost is removed by a transversal filter or the like using the GCR signal on the receiving side.

Due to the characteristics of a tuner for a ghost in this ghost removing device, when synchronizing separation is performed using a video signal after removing a ghost, a malfunction may occur in the synchronizing separation. As described in “Research on One Method of Video IF Compatible with Ghost Canceller” at the 1989 National Convention of the Institute of Television Engineers of Japan, pp. 249-250, the video IF circuit generates an IF output upon receiving an in-phase ghost and a quadrature ghost. The baseband signal is nonlinearly disturbed. If a ghost is removed using the disturbed video signal, a malfunction such as a synchronization flow may occur in the synchronization separation circuit. This phenomenon will be described below.

First, the case of an in-phase ghost will be described. IF-AGC (Auto Ga
In an in-control circuit, a peak AGC circuit for controlling a video amplitude level to be constant is generally employed. The response characteristic of the AGC circuit is such that it has a response that is fast enough to operate the AGC by following a flutter ghost generated in an aircraft or the like. For this reason, when an RF signal to which an in-phase ghost having a delay time of about several microseconds is received is received, in the AGC circuit, since the video signal including the in-phase ghost has a large amplitude level, the vertical synchronization with the ghost superimposed thereon is performed. The AGC works so that the signal amplitude including the part becomes constant. For this reason, in the output of the AGC circuit, the waveform of the ghost component in the vertical synchronization portion is different from the ghost waveform in which only the ghost edge component is left without preserving the shape of the original in-phase ghost waveform, that is, a nonlinear ghost waveform. Become. However, the ghost linearity of the ghost in the video signal portion is preserved. Therefore, the ghost added to the video part after the ghost is removed is not nonlinearly distorted, so the ghost can be removed correctly.However, the vertical synchronization part has to add a distorted waveform as a result by removing the nonlinear ghost. As a result, waveform distortion, which is higher than the pedestal level, so-called sag occurs. Since the vertical synchronizing signal is distorted in this way, when the synchronizing signal is separated from the video signal after the ghost removal by the sync separation circuit, the vertical synchronizing signal may not be correctly separated and a vertical synchronization flow may occur. Was. As a countermeasure, it has been reported that when the IF-AGC circuit is changed from the peak AGC circuit configuration to the keto @ AGC circuit configuration, nonlinear distortion of the vertical synchronization signal at the time of in-phase ghost can be reduced.

Next, the case of an orthogonal ghost will be described. When an orthogonal ghost having a relatively long delay time is added, the ghost waveform after the IF signal processing appears to be vertically shifted with respect to the image at the position where the orthogonal ghost is added if the linearity is similarly preserved. Should be a very different shape. However, the television receiver IF
Since the circuit is not perfectly synchronous detection, the ghost changes the detection axis for detecting carrier reproduction, so that the higher the degree of modulation, that is, the higher the white level of the video signal, the greater the ghost waveform added to the video. A luminance step occurs, and the image is distorted with a luminance step as if an in-phase ghost or a reverse-phase ghost were attached. Also,
In a place close to the black level, this luminance step hardly occurs. The ghost in the luminance step portion is removed from this video signal, but as a disadvantage, a new distortion waveform is added to another portion. Therefore, the fluctuation of the detection axis is reduced by increasing the time constant of the detection carrier reproducing PLL of the IF signal processing circuit, and the response of APC (Auto Phase Control) is slowed, so that the characteristics of the synchronous signal detection can be approximated. The luminance step when orthogonal ghost is added is reduced.
Thus, the amount of distortion to be newly added is reduced.

[0006]

The ghost removing apparatus according to the prior art described above has the following problems and will be described. First, the problem with the in-phase ghost will be described. As described above, by increasing the time constant of the AGC and delaying the response, the nonlinear distortion of the vertical synchronization signal portion due to the in-phase ghost can be reduced. There is a problem that fluttering ghosts cannot be removed because they cannot follow. In addition, the nonlinear distortion of the in-phase ghost can be eliminated by the keyed AGC, but since there is no nonlinear distortion in the video portion, the tuner circuit needs to be changed, which leads to an increase in cost.

Next, the problem of the ghost removing device for the orthogonal ghost will be described. In the related art, the distortion component is reduced even after the ghost is removed, but a distortion waveform is added to a level lower than the pedestal level, which may cause a malfunction in the synchronization separation. APC
Although the luminance step can be reduced by slowing the response, if various types of ghosts in the field are added, a distortion signal may be generated below the blanking level after the ghost is removed. For example, 100
When the orthogonal ghost is added to the% white square wave, after the ghost is removed, the trailing edge of the video signal waveform may be greatly distorted below the pedestal level. In this case, depending on the place where the ghost occurs and the size of the ghost There is a possibility that a malfunction occurs in the sync separation circuit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to correct the distortion of a video signal after performing a ghost removal process and to operate the synchronization signal separation circuit incorrectly. It is an object of the present invention to provide a television receiver suitable for preventing the problem.

[0009]

In order to achieve the above-mentioned object, a television receiver according to the present invention provides a television receiver having a ghost removal process performed by a transversal filter. A correction circuit for correction is provided, and an output signal of the correction circuit is input to a synchronization separation circuit to perform synchronization separation.

The correction circuit has an adder for adding a vertical cycle gate pulse signal (a gate pulse signal whose period corresponding to the vertical synchronizing signal is a Low level) and a video signal subjected to ghost removal processing. The distortion of the vertical synchronization signal portion caused by the ghost removal processing of the transversal filter is corrected by increasing the level of the vertical synchronization signal portion by the adder.

Further, the video signal subjected to the ghost removal processing by the transversal filter may be pedestal clipped and then input to the correction circuit. Further, the pedestal signal in the back porch period of the video signal input to the transversal filter may be clamped to a predetermined level.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to FIGS. FIG.
It is a block diagram showing one embodiment of a television receiver concerning the present invention. R input via antenna 101
The F signal is input to the tuner 102. Tuning microcomputer 1
04 is a tuner 102 for transmitting a desired channel signal to be tuned.
The tuner 102 outputs a signal obtained by converting the signal of the channel into an intermediate frequency. This intermediate frequency signal is input to the video IF signal processing circuit 105,
The video IF signal processing circuit 105 outputs a baseband video signal. This video signal is input to the clamp circuit 106 and the synchronization separation circuit 113. First, the synchronization separation circuit 113 separates and outputs a horizontal synchronization signal and a vertical synchronization signal from the output video signal of the video IF signal processing circuit 105,
At the same time, a color burst signal is extracted and 4f having a frequency of 14.32 MHz synchronized with the color burst signal.
An SC clock signal is output. This clock signal is generated by a digital circuit for generating various digital pulse signals, which will be described below, and an A / D converter 107 and a D / A converter 110.
Clock signal. Sync separation circuit 1
The output from 13 is a clamp pulse generation circuit 114, a video gate circuit 103, a GCR gate generation circuit 115, and a vertical synchronization gate generation circuit 116 in the distortion correction circuit 121.
Is input to That is, in the present embodiment, the horizontal and vertical synchronization signals output from the synchronization separation circuit 113 are supplied to four circuits. Hereinafter, the operation of each circuit in these four routes will be described in order.

First, a route supplied to the clamp pulse generating circuit 114 will be described. The clamp pulse generation circuit 114 delays the clamp pulse based on the 4 fsc clock signal based on the horizontal synchronization signal output from the synchronization separation circuit 113, and sets the clamp pulse at a timing falling within the back porch period of the video signal having a predetermined width. Generate and output a signal. Then, based on the clamp pulse signal, the clamp circuit 106 performs a so-called pedestal clamp for setting the pedestal signal in the back porch period of the input video signal to a predetermined level,
The video signal clamped to a certain level of potential is input to the A / D converter 107. The A / D converter 107 converts the digital video signal into a digital video signal based on the aforementioned 4 fsc clock signal, and outputs the digital video signal to the transversal filter 108. The transversal filter 108 performs ghost removal processing using a plurality of tap coefficients that can be set by the microcomputer 120 as a control circuit. The digital video signal output from the transversal filter 108 is input to a clip circuit 109 and a GCR extraction circuit 119, respectively.

Next, the route supplied to the GCR gate generation circuit 115 will be described. The GCR gate generation circuit 115 uses the horizontal and vertical synchronization signals output from the synchronization separation circuit 113 to set the period of the 18th line and the 281st line in the vertical retrace period to the High level, and the period of the other lines. Generates and outputs a GCR gate pulse signal which is a low-level digital signal. This GC
The R gate pulse signal is input to the GCR extraction circuit 119. In the GCR extraction circuit 119, the GC superimposed on the 18th line and the 281st line in the vertical retrace period of the video signal output from the transversal filter 108
The R signal is extracted using, for example, a logical operation element (such as an AND gate). The extracted GCR signal is transmitted to the microcomputer 1
20 is stored in a RAM built in the microcomputer 120, for example. The microcomputer 120 uses this RA
Based on the extracted GCR signal stored in M, a tap coefficient used for the ghost removal processing executed by the transversal filter 108 is calculated and supplied to the transversal filter 108. This tap coefficient is calculated based on the extracted GCR
A signal and a ROM built in the microcomputer 120, for example.
The ghost information is obtained by comparing a reference GCR signal stored in advance in the data and performing a correlation operation to detect a delay time and a level as ghost information. The tap coefficient is gradually updated so that the extracted GCR signal approaches the reference GCR signal, and the tap coefficient is updated until the ghost is suppressed and converges (the level and phase of the extracted GCR signal and the reference GCR signal substantially match). The operation is repeated. The updating operation of the tap coefficient to the transversal filter 108 performed by the microcomputer 120 described above is well known, and thus the detailed description is omitted.

Next, the route supplied to the video gate generation circuit 103 will be described. Video gate generation circuit 10
3 generates and outputs a digital video gate signal as shown by a waveform 304 in FIG. The video gate signal switches from the Low level to the High level near the middle between the end timing of the color burst signal and the video start point, and the H level slightly before the leading edge of the horizontal synchronization signal.
This is a gate signal that falls from the high level to the low level. This video gate signal is supplied to the clip circuit 1
09 is input. The clip circuit 109 further receives the video signal subjected to the ghost removal processing by the transversal filter 108 and the reference pedestal level preset by the microcomputer 120, and outputs the video gate signal to Hi.
During the period of the gh level, the video signal subjected to the ghost removal processing is compared with the reference pedestal level. If the input video signal is smaller than the reference pedestal level,
The pedestal level of the video signal is limited to the reference pedestal level and output. If the input video signal is larger than the reference pedestal level, the video signal is output as it is. The video signal output from the clip circuit 109 is converted into an analog video signal by the D / A converter 110 based on the 4 fsc clock signal. D / A converter 11
0 is input to the video signal processing circuit 111, and at the same time, the distortion correction circuit 121
Is input to one input terminal of an adder 123 which is one of the constituent circuits. In the video signal processing circuit 111, D / A
The analog video signal converted by the converter 110 is subjected to predetermined signal processing and output to the display device 112. The display device includes, for example, a cathode ray tube or a liquid crystal panel, and displays a video signal that has been subjected to signal processing by the video signal processing circuit 111.

Next, a route supplied to the vertical synchronization gate signal generation circuit of the distortion correction circuit 121 will be described. The distortion correction circuit 121 includes the transversal filter 10
8 for correcting distortion of a video signal including a vertical synchronizing signal which is distorted by the ghost removal processing. The distortion correction circuit 121 includes a vertical synchronization gate pulse generation circuit 11
6, a low-pass filter 117, an amplifier circuit 118, an adder 123, and a switching circuit 124. The vertical synchronization gate pulse generation circuit 116 has a period in which the period including the vertical synchronization signal of the video signal is Low based on the horizontal and vertical synchronization signals output from the synchronization signal separation circuit 113, for example, as shown by a waveform 204 in FIG. Level, and generates and outputs a gate pulse signal of a vertical cycle which becomes High level in other periods. In the waveform 204, High
Although only a portion where the level is switched from the low level to the low level is shown, the Lo level is changed after the timing of the trailing edge of the vertical synchronization signal signal.
The level switches from the w level to the High level. The vertical synchronization gate pulse signal described here is changed from High to Low.
The timing of switching to the level and / or the timing of switching from the Low level to the High level can be controlled and set by the microcomputer 120. The vertical synchronization gate pulse signal output from the vertical synchronization gate pulse signal generation circuit 116 is input to the low-pass filter 117. The low-pass filter 117 removes a high-frequency component of the vertical synchronization gate pulse signal, and outputs a signal with a dull edge component. The output signal from the low-pass filter 117 is
The signal is input to the amplifier circuit 118, and the amplitude level is amplified or attenuated to output a signal as shown by a waveform 205 in FIG. The amplification or attenuation of the amplifier circuit 118 is controlled by the microcomputer 120, and the waveform 205
A signal whose amplitude level is appropriately reduced from the amplifier circuit 118 is shown as an example. The output signal of the amplifier circuit 118 is input to one input terminal of the adder 123. Adder 123
An output signal from the D / A converter 110 as shown by a waveform 203 in FIG.
The adder 123 adds both signals, and generates the waveform 20 in FIG.
As shown in FIG. 6, a signal in which the level of the vertical synchronizing signal portion is increased is obtained. That is, assuming that the amplitude level of the waveform 203 that is the output signal from the D / A converter 110 is C,
Assuming that the amplitude level of the waveform 205, which is the output signal from the amplifier circuit 118, is D, the amplitude level E of the output signal from the adder 123 is C + D, as shown in the waveform 206. Thus, the transversal filter 10
8, the video signal distorted so that the amplitude level of the vertical synchronizing signal becomes small by the ghost removal processing of FIG.
The distortion can be corrected by increasing the amplitude of the vertical synchronization signal by the adder 123. The signal whose distortion has been corrected by the adder 123 is input to the other input terminal of the switching circuit 124. An output signal from the D / A converter 110 is input to the other input terminal of the switching circuit 124, and one of the signals is selected and output. Control of the switching circuit is performed by the microcomputer 120. When the microcomputer 120 supplies a tap coefficient to the transversal filter 108, that is, when the transversal filter performs ghost removal processing, the switching circuit 124 selects and outputs the output signal of the adder 123,
If 0 does not supply the tap coefficient to the transversal filter 108, that is, if the transversal filter does not perform the ghost removal processing, the microcomputer 120 selects the output of the D / A converter 110 and outputs it. Output a control signal to the This switching circuit 12
4 is input to the sync separation circuit 125. The sync separation circuit 125 compares the level of the predetermined slice level with the input signal level, detects that a portion having a level lower than the predetermined slice level is a sync signal, extracts the sync signal, and outputs the sync signal to the video processing circuit. Supply.

The operation and operation when the in-phase and quadrature ghosts are superimposed on the video signal in the configuration of the embodiment according to the present invention will be described below. The case where the in-phase ghost is superimposed will be described with reference to FIG. 2, and the case where the orthogonal ghost is superimposed will be described with reference to FIG.

(1) When In-phase Ghost is Superimposed In FIG. 2, a waveform 201 is an enlarged view of the vicinity of the leading edge of the vertical synchronizing signal in the vertical blanking period of the video signal, and has an H / 2 cycle. Equivalent pulse and H / 2
And a vertical synchronizing signal obtained by synthesizing a cutting pulse having a period, and an in-phase ghost is superimposed with a delay time τ. Among the in-phase ghosts, the ghost of the cutting pulse is indicated by a slanting line falling left and the ghost of the vertical synchronization signal is indicated by a slanting line falling rightward. The amplitude level of the vertical synchronization signal at this time is A. This waveform 201 is an ideal waveform when the linearity of the in-phase ghost is preserved. However, in actuality, as shown in a waveform 202, the output signal of the video IF circuit 105 has the linearity of the equivalent pulse and the cut pulse. Although the characteristic is preserved, the in-phase ghost near the leading edge of the vertical synchronizing signal is not preserved in linearity due to the AGC operation of the video IF circuit 105, and becomes a differential non-linear ghost. The amplitude level at this time is B.

When the signal of this waveform 202 is subjected to the ghost removal processing by the transversal filter 108, the ghost of the equivalent pulse and the cut pulse whose linearity is preserved, which is indicated by the diagonally left-downward slant, is removed, but the ghost of the vertical synchronization signal is removed. Due to the influence of the nonlinear ghost ahead, the level of the vertical synchronizing signal after the nonlinear ghost is raised. As a result, the amplitude level of the vertical synchronization signal portion becomes B
Is smaller than C. If such a signal is input to the sync separation circuit 125 to perform sync separation processing, a malfunction may occur. That is, the sync separation circuit 125 compares the input video signal with a signal having a level lower than the predetermined slice level 208 as a sync signal and separates the signal. If it does not exceed (below) 208, the slice level 20
Since it is larger than 8, it is determined that the signal is not a vertical synchronization signal.

Therefore, in the present invention, the amplitude separation of the vertical synchronizing signal in the video signal output from the transversal filter 108 is increased, and the sync separation is determined by comparing with the slice level 208 in the sync separation circuit 125. It is intended to be performed accurately.
Specifically, as described above, the vertical synchronizing gate pulse generating circuit 116 generates a gate pulse signal whose level in the vertical synchronizing signal period is Low as shown by the waveform 204, and outputs the gate pulse signal to the low-pass filter 117 and the amplifying circuit. 1
The waveform and the amplitude level are adjusted by the
5 is added to the video signal (waveform 203) output from the transversal filter 108 by the adder 123 to obtain the video signal output from the transversal filter 108. This is to increase the amplitude level of the vertical synchronizing signal portion in the signal. The amplitude level of the vertical synchronizing signal portion of the video signal output from the adder 123 is the waveform 206
, C + D = E, which is sufficiently smaller than the slice level 208 as shown by the waveform 207.
Therefore, erroneous detection and malfunction of the synchronization signal of the synchronization separation circuit 125 are prevented. It should be noted that the waveform 207 corresponds to the sync separation circuit 1
The low-pass filter (not shown) included in 25 removes the equivalent pulse and the cut pulse, which are high frequency components, and shows a signal from which a vertical synchronization signal portion is extracted.

(2) When orthogonal ghost is superimposed In FIG. 3, a waveform 301 is obtained by adding an orthogonal ghost with a delay time τ to a video signal of one horizontal scanning cycle including a 100% white square wave. This shows an ideal waveform when the linearity of the orthogonal ghost is preserved. Actually, the output of the video IF circuit 105 is the waveform 30
As shown in FIG. 2, a luminance step is added to the video portion, and a differentiated non-linear ghost is added between the trailing edge of the video portion and the leading edge of the horizontal synchronization signal. When the signal of the waveform 302 on which such orthogonal ghost is superimposed is input to the transversal filter 108, the orthogonal ghost (luminance step portion) is removed by the ghost removal processing. Due to the effect of the differential non-linear ghost added between the leading edge and the leading edge, a new ghost waveform is added to the trailing edge of the video portion, or a large waveform distortion below the pedestal level (see waveform 303). (Hereinafter simply referred to as waveform distortion). When such a video signal is input to the synchronization signal separation circuit 125 to perform the synchronization separation processing, a malfunction may occur as in the case of separating the vertical synchronization signal described above. That is, the synchronization signal separation circuit 125 compares the input video signal with a predetermined slice level 306 and determines a signal of a lower level as a synchronization signal and separates the signal. If less than
The waveform distortion is erroneously determined as a horizontal synchronization signal.

Therefore, in the present invention, when a waveform distortion having a level equal to or less than the pedestal level is added to the video signal output from the transversal filter 108 during one horizontal scanning period, the pedestal level is changed to a predetermined level. So that the sync separation circuit 12
5 to accurately determine the synchronization separation by comparison with the slice level 306. More specifically, as described above, as shown by the waveform 304 in FIG. 3, a period including a video area in one horizontal scanning cycle and a predetermined area after the trailing edge of the video area is a high level video gate signal. Generated by the gate generation circuit 103,
This video gate signal, transversal filter 108
Signal and microcomputer 120 after ghost removal processing
Is input to the clipping circuit 109. And the video gate signal is Hi
During the period of the gh level, the video signal subjected to the ghost removal processing is compared with the reference pedestal level, and when the input video signal is smaller than the reference pedestal level,
As shown in a waveform 305, the pedestal level of the video signal is limited to a reference pedestal level (waveform distortion component is cut) and output. Thus, even when a waveform distortion having a level lower than the slice level 306 is added to the video signal subjected to the ghost removal processing by the transversal filter 108, the clipping circuit 109 removes the waveform distortion component and removes the lower limit of the pedestal level. Since the value is set to be constant, the influence of waveform distortion in the synchronization separation circuit 125 can be reduced and malfunction can be prevented.

As described above, according to the present invention, the distortion correction circuit 121 for correcting the attenuation of the amplitude level of the vertical synchronization signal when the video signal on which the in-phase ghost is superimposed is subjected to the ghost removal processing, and the video on which the quadrature ghost is superimposed. A clip circuit 109 for correcting (clip) distortion of a pedestal level when a signal is subjected to ghost removal processing is provided with two characteristic configurations. Therefore, according to the present invention, even if any ghost is superimposed on the video signal, it is possible to prevent a malfunction (synchronous flow or the like) of the sync separation circuit 125, and to stably display a ghost-free video of optimal quality stably. There is an effect that can be displayed. Further, even if the ghost canceling device according to the present invention is incorporated into a television receiver, it is not necessary to improve the video IF circuit or to improve the sync separation performance of the sync separation circuit 125 connected to the subsequent stage of the ghost removing device. Therefore, there is an effect that shortening the development time is also beneficial.

[0024]

As described above, according to the present invention, a malfunction of the sync separation circuit due to a ghost can be prevented, and a stable image can be displayed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a television receiver according to the present invention.

FIG. 2 is a signal waveform diagram of each circuit shown in FIG. 1, mainly illustrating an operation of a distortion correction circuit 121;

FIG. 3 is a signal waveform diagram of each circuit shown in FIG. 1, mainly illustrating an operation of a clip circuit 109;

[Explanation of symbols]

101: antenna, 102: tuner, 103: video gate generation circuit, 105: video IF circuit, 106: clamp circuit, 108: transversal filter, 109 ...
Clip circuit, 111 ... Video signal processing circuit, 112 ... Display device, 113 ... Sync separation circuit, 114 ... Clamp pulse generation circuit, 115 ... GCR gate generation circuit, 116 ...
Vertical synchronization gate pulse generation circuit 117 117 low-pass filter 118 amplifier circuit 120 microcomputer 121
Distortion correction circuit, 123 ... adder, 124 ... switching circuit, 1
25 ... Sync separation circuit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takahiro Mizuguchi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Digital Media System Division of Hitachi, Ltd. 5C020 AA35 BA03 BA05 BA07 BA09 BB14 5C021 PA12 PA13 PA34 PA62 PA66 PA86 SA02 SA03 YA22 YA40

Claims (13)

[Claims] 1. A transversal filter for performing processing for removing a ghost from a video signal in a television signal based on a ghost removal GCR signal inserted into the television signal, and a transversal filter. A synchronization separation circuit that separates a synchronization signal from the ghost-removed video signal, and a video processing circuit that performs video processing on the video signal output from the transversal filter using the synchronization signal separated by the synchronization separation circuit. The television receiver comprising: a correction circuit for correcting a level of a period including a vertical synchronization signal of the video signal subjected to the ghost removal processing,
A television receiver, wherein the video signal corrected by the correction circuit is input to the synchronization separation circuit. 2. A control circuit for outputting a control signal based on a difference between a ghost removal GCR signal inserted into a television signal and a pre-stored reference GCR signal, and a control signal from the control circuit. A transversal filter that performs processing for removing a ghost from a video signal in a television signal, a synchronization separation circuit that separates a synchronization signal from a video signal that has been subjected to the ghost removal processing by the transversal filter, and a transversal filter. A video processing circuit that performs video processing on the output video signal using a synchronization signal separated by the synchronization separation circuit, wherein the vertical synchronization signal of the ghost removal-processed video signal is A correction circuit for correcting the level in the period including the video signal, and the image corrected by the correction circuit. A television receiver, wherein an image signal is input to the sync separation circuit. 3. The control circuit according to claim 2, wherein the control circuit is configured to control the GCR signal and a reference G signal.
3. The method according to claim 2, wherein a difference between a level and a phase of a CR signal is detected to generate a tap coefficient used for a ghost removal process of the transversal filter, and the tap coefficient is output as the control signal. Television receiver. 4. The television receiver according to claim 2, wherein the correction circuit has an adder for adding a gate pulse signal having a vertical period and the video signal subjected to the ghost removal processing. 5. The television receiver according to claim 4, wherein said gate pulse signal is inputted to said adder via a low-pass filter. 6. The correction circuit includes a switching circuit that selects one of the output signal of the adder and the video signal on which the ghost removal processing has been performed, and outputs the selected signal to the synchronization separation circuit.
5. The television according to claim 4, wherein when the transversal filter performs a ghost removal process, the control circuit controls the switching circuit so as to select and output an output signal of the adder. John receiver. 7. A vertical synchronizing gate signal generating circuit for generating and outputting a gate pulse signal of a vertical cycle in which a period including a vertical synchronizing signal of the video signal is at a low level; A low-pass filter that removes a high-frequency component of a gate pulse signal from a signal generation circuit; an amplification circuit that amplifies / attenuates an output signal of the low-pass filter; an output signal of the amplification circuit and a video signal that has been subjected to the ghost removal processing And a switching circuit that selects one of the output signal of the adder and the video signal on which the ghost removal processing has been performed, and outputs the selected signal to the synchronization separation circuit. When performing a ghost removal process, the control circuit controls the switching circuit so as to select and output an output signal of the adder. Television receiver according to claim 2. 8. The amplification circuit according to claim 7, wherein the amplification / attenuation is controlled by said control circuit.
A television receiver according to item 1. 9. A clip circuit for clipping a pedestal level of a video signal from the transversal filter to a preset reference pedestal level, and a D / A converter for converting an output signal of the clip circuit into an analog signal. 3. The television receiver according to claim 2, wherein an output signal of the D / A circuit is input to the video processing circuit. 10. A clipping circuit for clipping a video signal from the transversal filter to a preset reference pedestal level, and a D / A converter for converting an output signal of the clipping circuit into an analog signal. D /
8. The television receiver according to claim 6, wherein an output signal of the A circuit is input to the adder, the switching circuit, and the video processing circuit as a video signal subjected to the ghost removal processing. Machine. 11. The clipping circuit according to claim 11, wherein when a video signal from said transversal filter is smaller than said reference pedestal level, said clipping circuit clips said pedestal level to said reference pedestal level. The television receiver according to 9 or 10. 12. The system according to claim 9, wherein said reference pedestal level is provided from said control circuit.
The television receiver according to any one of the above. 13. The apparatus according to claim 1, further comprising a clamp circuit for clamping a pedestal signal to a predetermined level in a back porch period of a video signal input to said transversal filter. Television receiver.