JPS6015188B2 - Jitter correction device for video playback equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to a jitter correction device for a video playback device.

In particular, the present invention relates to a video playback diamond jitter correction device comprising a pseudo composite video signal generation device.
DESCRIPTION OF THE PRIOR ART When reproducing a television image on the screen of a television receiver according to a composite video signal reproduced by a video reproducing device such as a video disc, jitter tends to occur, resulting in jitter along the vertical direction. Weaving of the television image is observed.

This jitter can be solved by automatic frequency control (automatic frequency control), which extracts the phase of the composite video signal supplied from the video playback device to the television receiver and the horizontal synchronization signal of the composite video signal, and which is installed in the ordinary television receiver. AF below
This occurs according to the phase difference between the horizontal deflection signal and the phase of the horizontal deflection signal passed through the signal C. Such a phase difference between the composite video signal and the horizontal deflection signal is caused by the fact that while the AFC electrically stabilizes the frequency of the horizontal deflection signal, the video playback device is not able to reproduce the signal based on its structural characteristics. This is caused in the television receiver by reproducing the composite video signal from the television signal recording medium with a fairly low accuracy with respect to the signal phase. Therefore, in a television receiver having a structure in which the AFC time constant can be easily adjusted to a small value from the outside, the desired jitter on the screen can be reduced relatively easily. However, like many television receivers that are already in common use in households, the AFC time constant cannot be adjusted. When used as a monitor television receiver for playback, the AFC time constant changing method described above requires modification of the monitor television, so it cannot be adopted mainly from the viewpoint of serviceability. . A jitter correction method that can easily remove the above-mentioned jitter without making this modification is shown in US Pat. No. 3,681,522. The technology is that the reproduced composite video signal is not directly supplied to the monitor television receiver, but instead of the reproduced horizontal synchronizing signal contained therein, the reproduced composite video signal is A modulated horizontal synchronizing signal obtained by phase modulating the synchronizing signal is used, and the converted composite video signal is supplied to a monitor television receiver. In other words, the above-mentioned U.S. patent basically states that the position between the composite video signal supplied to the display tube of a monitor television receiver and the output signal from the AFC provided in said receiver is The horizontal synchronizing signal of the reproduced composite video signal is phase-modulated by an amount corresponding to the phase difference, and the phase difference is compensated in advance in the video reproduction device. Comparing the above method of changing the AFC time constant of a monitor television receiver with the method of pre-compensating for the phase difference in a video playback device disclosed in the above-mentioned US patent, ``the latter method is The former method is superior in that it cannot completely compensate for the phase difference in question, whereas the former method cannot reduce the phase difference to zero.In the jitter correction method disclosed in the above-mentioned U.S. patent, Jitter
The system must be adjusted so that the modulation signal that phase modulates the horizontal synchronization signal of the reproduced composite video signal better corresponds to the frequency characteristics of the AFC provided in the monitor television receiver in order to minimize

If the frequency characteristics of the AFC of the receiver are known in advance, it is easy to design a means for adjusting the jitter correction means that corresponds to the frequency characteristics of the APC. Since there are various types of AFC frequency characteristics in John receivers, it is not necessarily easy to provide adjustment means for the jitter correction method that can be applied to each individual receiver. The above US patent applies to different types of televisions. AF with various frequency characteristics of John receiver
It does not disclose adjustment means that can be adapted to C. In other words, there is room for improvement in the US patent for practical use. SUMMARY OF THE INVENTION In short, the present invention provides a video playback device connected to a monitor television receiver equipped with AFC and for reproducing a composite video signal of any standard television system, including a jitter correction device, The horizontal synchronizing signal of the reproduced composite video signal is phase-modulated by an amount related to the phase difference between the composite video signal provided to the display tube of the monitor television receiver and the AFC output signal of the monitor television receiver, and the phase means for presenting the transformed composite video signal as a modulated horizontal sync signal;
The feature is that the horizontal synchronization signal includes a vertical and horizontal synchronization signal and a mark signal existing in the phase range of the video signal in order to provide a pseudo composite video signal to the monitor television receiver through the jitter correction device, and the horizontal synchronization signal is a standard signal of the video playback device. means for generating a pseudo-composite video signal that is shifted in phase relative to a horizontal synchronization signal of a television system, whereby said phase modulating means observes a mark indicia on a display tube screen corresponding to said mark signal; The present invention relates to an adjustable jitter correction device for a video playback device.

In a preferred embodiment of the present invention, the horizontal synchronization signal is
Two signs are desired on the display tube screen, consisting of two types of horizontal synchronization signals, one of the leading and the other of the lagging type.

Adjustment of the phase modulation means is therefore easily accomplished by bringing the two markers close together.
The leading-phase horizontal synchronizing signal and the lotus-phase horizontal synchronizing signal are included in a pseudo composite video signal that appears alternately after the peak of one field of the leading-phase horizontal synchronizing signal and one field of the lagging-phase horizontal synchronizing signal. Preferably, the starting point of each field is such that the two marking lines produced by the mark signal intersect at a position away from the top or bottom edge of the display tube screen of the television receiver. It is shifted from the vertical sync signal so that the characteristics of the AFC and the state of adjustment can be easily observed on the screen. Such a pseudo-composite video signal may be pre-recorded on a recording medium of a video playback device, such as a video tape or a video disc.

Alternatively, such a pseudo-composite video signal may be generated by an electrical circuit serving that purpose.
Such a circuit can be constructed relatively easily. Therefore, the main object of the present invention is to provide a jitter correction scheme for a video playback device comprising a jitter correction circuit with adjustment means that can be easily adapted to the AFC of a monitor television receiver.

Furthermore, the present invention provides a jitter correction method for a video playback device comprising a jitter correction circuit having an adjustment means that allows the user to easily and easily adjust the adjustment means while observing a display tube screen of a monitor television receiver. It provides: Furthermore, the present invention provides an adjustment means and a pseudo for displaying on the display tube screen of the monitor television receiver the fixed adjustment state of said adjustment means in relation to the characteristics of the AFC of the monitor television receiver. It is an object of the present invention to provide a jitter correction device for a video playback device, which includes pseudo composite video signal generation means for generating a composite video signal.

Furthermore, the present invention provides means for phase modulating a horizontal synchronizing signal of a reproduced composite video signal, means for adjusting the amount of phase modulation, and a pseudo composite for displaying the adjustment process of the adjusting means on a screen of a display tube. the phase modulation means includes means for detecting a jitter component of a reproduction synchronization signal, and the jitter component detection means is of a speed detection type, that is, a type that detects a time differential of a phase change; It is therefore an object of the present invention to provide a jitter correction device for a video playback device that improves the frequency characteristics of a jitter detection signal.

The invention further provides means for phase modulating the horizontal synchronization signal of a reproduced composite video signal, and a pseudo-composite for producing an indicator on the screen of a display tube of a monitor television receiver indicating the adjustment status of said phase modulating means. means for generating a video signal, the phase modulation means comprising means for detecting a jitter component of a reproduced synchronization signal, and the jitter component is based on a pulse train corresponding to a trailing edge of a reproduced horizontal synchronization signal provided in a reproduced composite signal. It is an object of the present invention to provide a jitter correction device for a video playback device, which is adapted to detect jitter, thereby improving the accuracy of a jitter detection signal.

These and other objects, configurations, effects, and overall aspects of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 shows one embodiment of a jitter correction apparatus according to the present invention.

Basically, this embodiment consists of a video playback device VRA, such as a video disc player, and a monitor television receiver T.
It is equipped with a jitter correction circuit JCC connected between V and V. An input of the jitter correction circuit JCC is connected to receive a pseudo-composite signal from a pseudo-composite video signal generator PSG. Although the pseudo composite signal generator PSG is prepared independently of the video playback device VRA and the jitter correction circuit JCC of the illustrated embodiment, the generator PSG may also be provided in the jitter correction circuit JCC in the form of an electric circuit. Alternatively, the pseudo composite video signal may be provided in the video reproducing apparatus VRA in the form of a recording medium on which the pseudo composite video signal is recorded, as will be described in more detail below.
A composite video signal reproduced from the video reproduction device VRA is supplied to the jitter correction circuit JCC. Specifically, the jitter correction circuit JCC includes a synchronization signal separation circuit 1 for separating the horizontal synchronization signal from the reproduced composite video signal, and a synchronization signal removal circuit 2 for removing the horizontal synchronization signal from the reproduction composite video signal. , a horizontal synchronization signal phase modulation circuit 3 for phase modulating the separated horizontal synchronization signal, a video signal from which the horizontal synchronization signal has been removed from the synchronization signal removal circuit 2, and a phase-modulated horizontal signal from the horizontal synchronization signal phase modulation circuit 3. A mixing circuit 4 is provided for mixing synchronizing signals and presenting a synthesized composite video signal that is phase modulated with the horizontal synchronizing signal. On the other hand, the monitor television receiver is supplied with a video signal system including an intensifier 5 for amplifying the synthesized composite video signal and providing the intensified signal to a display tube 6, and the synthesized composite video signal. Horizontal sync signal separator 7, separated horizontal sync signal (phase modulated as described above)
, and a deflection system including a deflection circuit 9 to which the output of the AFC 8 is supplied and for driving the horizontal deflection coil of the display tube 6 . AF of monitor television receiver
C8 is a voltage controlled oscillator 1 that oscillates near the horizontal frequency.
0, a phase comparator 11 that compares the phase of the separated (phase modulated) horizontal synchronizing signal and the output of the voltage controlled oscillator 10, and an average level for an error for controlling the voltage controlled oscillator 10. and an integrator 12 for detection.

If the open loop transfer function of AFC8 is F(S), as is well known, the phase of the input signal? Phase of IC and output signal? o
The following equation holds between . ? 0=. chapter) Gume
...■ Note that the open loop transfer function F(S) is the frequency characteristic G(S) of the integrator including the gain of the voltage controlled oscillator and the phase comparator.
Expressed as follows:

F(S)=G(S)/S...■The horizontal synchronizing signal phase modulation circuit 3 converts its transfer function C(S) into the open-loop transfer function of this AFC. It is configured such that it can be adjusted so as to be equal to the reciprocal of the output signal (AFC 8), thereby eliminating the phase difference between the composite video signal supplied to the display tube 6 and the output signal from the AFC 8.

At the air pole, the phase modulation circuit 3 has its transfer function C(S)
is constructed as expressed by the following equation. c(s) = equal sign = decimation ...... In the formula, the circuit configuration to achieve the component S is designed to detect the time differential of the phase fluctuation of the separated horizontal synchronization signal for jitter detection. This can be achieved by using a speed detection type jitter detection circuit.

In addition, the total component 'ma-shoe transfer function E(S
) can be realized by using a phase adjustment circuit that can adjust it so that E(S); 1/G(S).

Basically, this horizontal synchronizing signal phase modulation circuit 3 is constructed by connecting a speed detection type jitter detection circuit 13, a vibration/phase adjustment circuit 14, and a phase modulator 15 as shown in the figure. configured.

FIG. 2 shows an embodiment of a speed detection type jitter detection circuit 13 with excellent frequency characteristics.

This detection circuit includes a preprocessing circuit 16 for removing a horizontal synchronizing signal near the vertical synchronizing signal, as described below, a voltage controlled oscillator 17 that oscillates near the horizontal frequency, and an output from this voltage controlled oscillator. an integrator 18 for integrating
, a sampling circuit 19 for sampling the output from the integrator 18 using the output from the preprocessing circuit 16, a holding circuit 20 for holding the output from the sampling circuit 19, and a voltage control signal from the holding circuit as a control signal. A circuit connection 21 provides an output to the oscillator 17 and a circuit connection 22 derivates a jitter detection signal from the holding circuit. The above-mentioned preprocessing circuit 16 includes a differentiation circuit 23 that differentiates the reproduced horizontal synchronization signal in the separated synchronization signal.
, a level detection circuit 24 that detects the level of the differential output from the differentiating circuit 23 at a predetermined level of the differential output, and a vertical sync signal separator that separates the vertical sync signal from the separated sync signal obtained from the sync signal separator 1. It includes a circuit 25 and a NAND gate 26 that performs NAND processing on the output of the level detection circuit and the separated vertical synchronization signal. With regard to FIG. 3A, which shows the waveform of a composite video signal actually played back from a video playback device such as a video disc player, the played composite video signal has the leading edge (falling portion a) of the horizontal synchronization signal. When comparing the trailing edge (falling portion b) of the horizontal synchronization signal, it is observed that the sharpness of the front green of the horizontal synchronization signal is inferior to that of the rear green.

The reason for this is that in video disc players, the frequency band of the video signal is limited, so the waveform becomes dull in parts where sudden changes occur, and in the case of the leading edge of the horizontal synchronization signal, the video signal exists until just before that point. Therefore, the sharpness of the foreground green is thought to be inferior as a result of the sudden change. Therefore, as a signal for detecting jitter, it is better to obtain a pulse formed from the trailing edge of the horizontal sync signal with good sharpness, that is, a pulse train corresponding to the trailing edge pulse of the horizontal sync signal, for more accurate operation. You can expect it. FIG. 3B is a signal waveform diagram in the vicinity of vertical planking of each part of the preprocessing circuit 16 shown in FIG.

- Regarding the waveforms in Figure 3B, during the periods of the forward equivalent pulse, the vertical sync pulse, and the backward equivalent pulse, the horizontal synchronization signal
Two pieces are included in one horizontal scanning period (IH). In this specification, for ease of explanation, the period including the forward equivalent pulse, vertical synchronization pulse, and backward equivalent pulse will be referred to as "
collectively referred to as "vertical synchronization signal section". Because the cycle of pulses obtained from the trailing edge of the reproduced horizontal sync signal during the above-mentioned "vertical sync signal portion" is different from that of the pulses obtained in other parts of the reproduced composite video signal, It turns out that in order to detect the jitter based on the pulse train corresponding to the edges, it is necessary to remove the pulses corresponding to the trailing green of the horizontal synchronization signal in the section of the vertical synchronization signal part mentioned above. The pre-processing circuit 16 mentioned above is for accomplishing the above purpose. The detailed operation of this preprocessing circuit will be explained below with reference to the waveforms shown in FIG. 3B.
The differentiating circuit 23 to which the separated synchronizing signal shown in waveform a in FIG. 3B is input derives a differentiated output shown in waveform b in the same figure.

The differential output is input to the level detection circuit 24, where only the output portion above the level shown by the broken line of waveform b in the same figure is detected, and the signal shown in waveform c in the same figure is derived as the output. . On the other hand, the vertical synchronization signal separation circuit 25 serves to separate the vertical synchronization signal shown in waveform d in the figure from the separated synchronization signal input thereto. The vertical synchronization signal is separated with a slight delay from the actual vertical synchronization signal because the vertical synchronization separation circuit usually includes an integrating circuit therein. The NAND gate 26, which receives the output from the level detection circuit 24 and the separated vertical synchronization signal, exhibits an output shown in waveform e in FIG. 3B. From the waveform e, it is observed that only the pulse corresponding to the rear green of the reproduced horizontal synchronization signal occurring in the above-mentioned horizontal synchronization signal section is removed. In this way, a pulse train corresponding to the trailing edge of the reproduced horizontal synchronizing signal from which the reproduced horizontal synchronizing signal generated in the vertical synchronizing signal portion described above has been removed is derived as an output from the preprocessing circuit 16 and is supplied to the sampling circuit 19. Ru. Now, the operation of deriving the jitter detection signal based on the output from the preprocessing circuit 16 will be explained with reference to the waveforms in FIG. 3C showing the signal waveforms in blocks 17, 18, 19, and 20 of the circuit in FIG. do.

The oscillation output from the voltage controlled oscillator 17 (waveform a in FIG. 3C) is input to the integrating circuit 18, and an integrated output as shown in waveform b in the figure is derived. This integrated output is the above-mentioned pulse train (waveform C in FIG. 3C) corresponding to the trailing edge of the remaining reproduced horizontal synchronizing signal after removing the reproduced horizontal synchronizing signal in the section of the vertical synchronizing signal portion described above, and is generated by the sampling circuit 19. sampled by The sampled output is sent to the holding circuit 20
The holding output of waveform d in FIG. 3C is fed back to the voltage controlled oscillator and is also used as a jitter detection signal during oscillation.
It is input to the phase adjustment circuit 14 through circuit connection 22 .
Next, the above-mentioned vibration and phase adjustment circuit 14 will be explained in detail.

Frequency characteristic G of the integrator including the gain of the above-mentioned voltage-controlled oscillator and phase comparator in the monitor television receiver TV
(S) generally exhibits frequency characteristics as shown in FIG. 4A. Therefore, during this vibration, the frequency characteristics of the transfer function E(S) of the phase adjustment circuit 14 must be adjusted as shown in FIG. 5A. From a practical point of view, the falling part of the characteristic curve shown in Figure 4A in the high frequency region can be ignored;
Therefore, the frequency characteristic G(S) of the integrator including the gain of the voltage controlled oscillator and phase comparator shown in FIG. 4A can be viewed as shown in FIG. 4B. Therefore, during vibration, the transfer function E(S) of the phase adjustment circuit 14 can be selected from a practical standpoint as shown in FIG. 5B. In FIG. 4B, the levels at the frequencies f, (=Kozo) and H2(i; Puhiko) are respectively K. and Q. K. Then, the transfer function G(S) of the integrator including the gains of the voltage controlled oscillator and the phase comparator is expressed as follows. G(S)=KO・Sensankichi Lord
...■Therefore, during vibration, the transfer function of the phase adjustment circuit 8(S)
must be as follows:

E(s) = zhi = jin/shibuzei.・．． ．．・．． ■Here, Q.

,K. and T. is a constant determined once the frequency characteristics of the integrator including the gains of the voltage controlled oscillator and the phase comparator are specified. Therefore, if the frequency characteristics of the voltage-controlled oscillator and the integrator, including the gain of the phase comparator, are not specified, they must be adjusted in the phase adjustment circuit 14 during oscillation, as is clear from equation (2) above. The variable parameters are listed in Q above.

,K. , and T. The variables Q, K, and T are related to . In principle, to determine these three parameters, the frequency characteristics of the characteristic G(S) as shown in FIG. 4A or 4B are measured over the entire frequency range, and from there
K, and T must be determined.

Also, according to these parameters, E that satisfies the above formula
The above-mentioned vibration and phase adjustment circuit 14 must be configured to have a transfer function of (S). It is extremely impossible to perform the above-mentioned work on a television receiver already installed in a general household, and it is hardly possible to put it into practical use. In this regard, the previous US patent leaves room for improvement. On the other hand, in order to be able to appropriately deal with the AFC characteristics of a monitor television receiver while visually observing the display tube screen of the monitor television receiver, without being conscious of the frequency characteristics of the AFC, the above vibration Of course, it would be very convenient if the phase adjustment circuit 14 could be adjusted.

The present invention achieves this objective as detailed below. An NTSC video disc player that rotates the video disc at a rate of 3 sub-rotations per second has 3 discs (g).
It has been observed that the following jitter components are hardly noticeable to those observing the display screen of a monitor television receiver.

It is also known that due to the fundamental characteristics of this type of player, it is dominated by jitter components of the three plates g and its harmonics. The APCs of various monitor television receivers whose characteristics are unknown can be classified as shown in Fig. 4 by classifying each AFC whose characteristics are unknown based on the position on the above-mentioned three frequency characteristic curves. The characteristics can be classified into any of characteristic curves a, b, and c.

In other words, the above-mentioned three frequencies are in the flat part of the high frequency range as shown in characteristic curve a, those in the mirror slope part of the intermediate frequency range as shown in characteristic curve b, and those in the low frequency range as shown in characteristic curve c. The three typical cases are those in the plateau of the region. Since the jitter component below the frequency of 30 Hg can be ignored from a practical standpoint as described above, each characteristic in FIG. 4C can be substituted by a, b, and c in FIG. 4D.

Therefore, the transfer characteristics required of the adjustment circuit 14 corresponding to the characteristics shown in FIG. 40 are the characteristics a', b' shown in FIG. 5C.
, and c'. Therefore, the adjustment circuit 14 adjusts the parameter K at the three capes g to the value K, , K2 or K3 of the monitor television receiver of the type corresponding to the characteristic curve a, b or c classified as above. If adjusted to match, the jitter-component of the three plates can be eliminated on the display screen of the corresponding monitor television receiver. This parameter K can be adjusted by adjusting the oscillation adjustment circuit 14A of the oscillation and phase adjustment circuit 14 described above, and the parameters Q and T
is adjusted by the phase adjustment circuit 1 of the phase adjustment circuit 14 during the above-mentioned vibration.
This is done by adjusting 48. Next, we will explain how the parameter K corresponding to the jitter component of the above-mentioned three caps is observed on the display tube screen of the monitor television receiver, and how the parameter K is adjusted. do. For conditioning, the present invention employs a pseudo-composite video signal specifically prepared for conditioning,
The pseudo composite video signal is inputted to the signal input terminal of the jitter correction circuit JCC so that it is displayed on the display tube screen of the monitor television receiver, and then adjusted while visually observing the image on the display tube screen. circuit 14
This is to make adjustments. FIG. 6 shows the waveform of the above-mentioned pseudo composite video signal in which the vertical synchronization signal train is compressed on the time axis, and FIG. 7 shows the waveform of the pseudo composite video signal in which the horizontal synchronization signal train is expanded in the time axis. The waveform of the video signal is shown.

6 and 7, the pseudo-composite video signal of the illustrated embodiment is shown at a predetermined time 7 after each vertical synchronization signal. That is, for each area A and B in FIG. 6, the repetition period of the horizontal synchronizing signal is (day-6H), and the first mark signal is placed at a predetermined position, for example, at the center of each line of the first adjustment signal. P, and the return period of the horizontal synchronization signal is (H+8H), and a second mark signal P2 is added at a predetermined position, for example, at the center of each line of the second adjustment signal. It is constructed by alternately combining the second adjustment signal and the second adjustment signal. Generally, the positions of the first and second mark signals are as follows:
The ratio of the repetition period (H-6H) of the horizontal synchronization signal of the first adjustment signal to the time t from the horizontal synchronization signal of the first adjustment signal to the first mark signal P is the horizontal synchronization of the second adjustment signal. The position is selected to be equal to the ratio of the repetition period (H+6H) of the horizontal synchronizing signal of the second adjustment signal to the eyebrow gain 2 from the signal to the second mark signal P2. In FIG. 1, the pseudo-composite video signal generator G is loosely configured to generate the above-mentioned pseudo-composite video signal shown in FIGS. 6 and 7. The pseudo composite video signal generator PSG will be described in more detail later. When the above-mentioned pseudo composite video signal is input to the monitor television receiver TV through the jitter correction circuit JCC, a set of lines as shown by solid lines and dotted lines in FIG. 8 appears on the display tube screen of the monitor television receiver. It is hoped.

The horizontal period of the first adjustment signal part is shorter than that of the standard horizontal period, so that the marking caused by the mark signal P of the first adjustment signal moves from the upper right area to the lower left area on the screen as shown by the solid line. Take on the tendency to extend. On the other hand, since one horizontal period of the second adjustment signal portion is longer than the standard horizontal period, the mark caused by the mark signal P2 on the screen extends from the upper left area to the lower right area on the screen, as shown by the point Sosen. Take the mirror direction that exists. However, since the monitor television receiver is equipped with AFC, the monitor television receiver operates to perform horizontal deflection in synchronization with a phase-shifted horizontal synchronizing signal according to the characteristics of the AFC. Thus, the marker lines produced by the mark signals P and P2 of the pseudo composite video signal tend to be bent to extend vertically in accordance with the AFC characteristics of the monitor television receiver. The bending of these lines indicates the AFC characteristics of the monitor television receiver, and
Corresponds to the FC step response. Consequently, the APC characteristics of a monitor television receiver can be determined by looking at the display tube screen of the receiver. In order to adjust the adjustment circuit 14 of the jitter correction circuit JCC, it is sufficient to adjust the above-mentioned lines so that they are close to each other as shown in FIG. 8B. In the illustrated embodiment, the first and second adjustment signals for each field are 7 from the vertical synchronization signal. The two indicator lines on the screen are phase shifted by the time 7 shown above. Depending on the desired location on the screen away from the top or bottom edge of the frame on the screen. It is desirable to locate the intersection of these two lines near the center of the frame on the screen because the intersection can be easily observed. As shown in FIG. 8B, the middle W between the above two lines desired on the screen can be made wider or narrower by adjusting the above-mentioned swing adjustment circuit 14A, thereby minimizing the middle W. When the above parameter K is the corresponding parameter K,,K of AFC specific to the adopted monitor television receiver.
2, or K3. As shown in FIG. 8C, unlike the case in FIG. 8B, the solid line and the dotted line may not partially match each other. This occurs when the above-mentioned phase adjustment circuit 14B is not properly adjusted. Next, a specific example of the phase adjustment circuit 14B will be explained.

In principle, this phase adjustment circuit 14B can have any configuration as long as it satisfies the above formula (2), but considering the convenience of the adjustment operation, the previously set parameter K is the same as the parameter Q and It is desirable to have a configuration that does not change during the T adjustment process. 9A, 98, and 9C all show embodiments of phase adjustment circuits that meet this requirement,
10A, 10B, and 10C show frequency response characteristic diagrams of each corresponding circuit.

The transfer characteristic of the first adjustment circuit shown in FIG. 9A is expressed by the following equation.

Ea(S)=R ear sheep owner;-. Young Ouji≦S -…”■T
ia NiCne・R・a●Xq. =R,a+R2a-R,a
・X R・a+RneOS×SI Here, fne=; With three branches, fia/f(H)a=
Cia is selected so that C(i-,)a/Cia=constant.

The transfer function of the second adjustment circuit shown in FIG. 9B is expressed by the following equation. Eb(S)=R; black main; ●. Lord Juumote Ashigoto S...
…■Tib NiCib (Rib+Rlb)R, hR ground+R
．． P′, b+R, bR2bQb=(R, b+R, bXR
, b+R2b) where Cib is fib/f(i-,
)b=C(i-,)b/Ci=constant.

The transfer function of the third adjustment circuit shown in FIG. 9C is expressed by the following equation.

EC(S)=C; given; -. Main manager's voice S ---
- ■T'C Ni (C Matsuju C31) RCCiCC evil + C3C
IC + C3C upper 9 QiC ni (C young + C3i) (CIC + C2C) where,
C3; is selected so that Qic/Q(M)c=constant.

The procedure for adjusting the phase adjustment circuit 14 during operation, which includes one of these circuits as the phase adjustment circuit 14B, will be described below.

First, the contact of the switch SW is connected to terminal 0, and the gain of the above-mentioned center adjustment circuit 14A is adjusted so that the above-mentioned center W desired on the display tube screen of the monitor television receiver becomes zero. Next, connect the contact of switch SW to terminal 1.
9A, 9B, or 9C, proceeding sequentially from to n.
By changing the variable resistance of each phase adjustment circuit as shown in the figure for each contact of the switch SW connected to each terminal, the terminals are constructed such that a screen image as shown in Figure 8B in which the above two lines overlap each other appears. and a variable resistor, whereby an optimal adjustment of the jitter correction circuit JCC can be made to correspond to the AFC of the employed monitor television receiver. Therefore, by using the above-mentioned pseudo composite video signal, the jitter correction circuit JCC can be adjusted very easily while viewing the screen image of the monitor television receiver that is actually used. Next, the pseudo composite video signal generator PSG will be explained in more detail. Very practically, recording media such as video discs or video tapes, especially recording media for viewing, are equipped with a sixth recording medium.
and the pseudo composite video signal described above with reference to FIG. 7 is recorded. In this embodiment, the recording medium is set in a video playback device VRA for video playback. The reproduced pseudo composite video signal thus obtained is input to the monitor television receiver TV through the jitter correction circuit JCC. In this example,
It can be seen that the pseudo composite video signal generator PSG is included in the video reproduction device VRA. In this embodiment, it is also possible to provide an explanation of the adjustment method before the area where the pseudo composite video signal is recorded, and in that case, the user can easily and easily make adjustments according to the explanation. . The above pseudo-composite video signal may be generated by separately configuring a pseudo-composite video signal generator.

Figure 11 shows such a pseudo composite video signal generator OreG.
1 is a block diagram of a preferred embodiment of the present invention. The illustrated generator PSG comprises an oscillator 40 precisely controlled to oscillate at a frequency of 6 discs. The excavator 40 may be composed of a multi-pipulator that generates a square wave. The output from the oscillator 40 is input to a differentiation circuit 42, and the differentiation output is derived as a vertical synchronization signal. On the other hand, the output from the oscillator 40 is input to a frequency divider or binary counter 41,
The output from the binary counter 41 is input as a control signal to a voltage controlled oscillator 43 which is designed to oscillate near the horizontal frequency. This oscillator 43 can also be configured with a multipipulator that outputs a rectangular wave. The output from the oscillator 43 is input to the differentiating circuit 45, and the differentiating circuit 45
The differential output from is derived as a horizontal synchronization signal. The horizontal synchronization signal from differentiator circuit 46 and the vertical synchronization signal from differentiator circuit 42 are mixed by mixer 47, thereby presenting a series of synchronization signals. On the other hand, the output from the oscillator 43 is differentiated by the differentiating circuit 44, and then the differentiating circuit 4
A differential output having a polarity opposite to the differential output from 5 is derived as a mark signal. The mark signal from circuit 44 and the series of synchronization signals from mixer 47 are mixed by mixer 46 to provide the desired pseudo-composite video signal as shown in FIGS. 6 and 7. The operation will be explained.

The differentiating circuit 42 contributes to generating the vertical synchronization signal based on the rectangular wave output from the oscillator 40 as described above, while the binary counter 41 contributes to generating a binary signal synchronized with the generated vertical synchronization signal. Contributes to providing output. Voltage controlled oscillator 4
3 oscillates near the horizontal frequency in response to the binary output from the binary counter 41, its oscillation frequency increases at the level of one of the binary outputs, and the oscillation frequency increases at the level of one of the binary outputs. decrease at the other level. The differential output of one pole of these two sets of oscillation outputs is derived as a horizontal synchronization signal of the first and second adjustment signals a and b described in relation to FIG. The differential outputs of the other pole are derived as mark signals P and P2 described in connection with FIG. The vertical synchronization signal, two horizontal synchronization signals of different frequencies, and the mark signal are combined in mixers 46 and 47 to provide the desired pseudo-composite video signal as shown in FIGS. 6 and 7. The pseudo composite video signal generator PSG as shown in FIG. 11 can be incorporated into the jitter correction circuit JCC shown in FIG. Apart from this, the first and second
The adjustment signal is easily obtained by imaging with a flying spot scanner that scans vertical lines alternately at periods (H-6H) and (H+6H). In the embodiment described above, the pseudo-composite video signal comprises a pair of conditioning signals;
It is composed of the first and second adjustment signals a and b described in connection with FIG.

This embodiment is the most preferred type in which the two marker lines are adjusted to be close to each other. Alternatively, only one adjustment signal may be used for adjustment according to the invention. Furthermore, the phase difference between the starting point of each adjustment signal and the vertical synchronization signal may be set to zero. In this case, the intersection of the two marker lines appearing on the display tube screen will be near the top and bottom ends of the on-screen frame. Obviously, the invention includes these modifications. Although the invention has been described and illustrated in detail, each description is to be used by way of illustration only and not by way of limitation.
It goes without saying that the spirit and scope of the invention is limited only by the terms of the appended claims.

[Brief explanation of drawings]

1 is a block diagram of a jitter correction device according to the present invention, FIG. 2 is a block diagram of a jitter correction circuit provided in the embodiment of FIG. 1, and FIG. 3 is for explaining the operation of the embodiment of FIG. 2. A waveform diagram, FIG. 4 is a transfer characteristic diagram of the AFC of the horizontal oscillator provided in the monitor television receiver, FIG. 5 is a transfer characteristic diagram of the adjustment circuit provided in the embodiment of FIG. 1, and FIGS. FIG. 7 is a waveform diagram of the pseudo composite video signal used in the present invention, FIG. 8 is an observed view of the display tube screen of a monitor television receiver on which the pseudo composite video signal is displayed, and FIG. 9 is the first
Circuit diagrams of several embodiments of the phase adjustment circuit provided in the adjustment circuit of the embodiment shown in the figure, FIG. 10 is a corresponding transfer characteristic diagram of each embodiment shown in FIG. 9, and FIG. 11 is a pseudo composite 1 is a block diagram of a preferred embodiment of a video signal generator. Explanation of main drawing numbers, PSG...Pseudo composite video signal generator, VRA...Video playback device, JCC...Jitter correction circuit, TV...
...Monitor television receiver, 3...Horizontal synchronization signal phase modulation circuit, 13...Jitter detection circuit, 14...During vibration, phase adjustment circuit, 8...・・・
...AFC. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] 1. A composite video signal of any television system, which comprises vertical and horizontal synchronization signals and a video signal, is reproduced from a recording medium, and the reproduced composite video signal is subjected to horizontal deflection. A jitter correction device for a video playback device for supplying to a monitor television receiver, comprising an automatic frequency control (AFC) circuit for adjusting the playback of the played composite video signal in response to a played back composite video signal. means for detecting a phase variation in the video signal caused by the AFC and an output from the AFC for producing jitter on the screen of the monitor television receiver in response to the phase variation detection output; compensation signal generating means for presenting a compensation signal for compensating for a phase difference between the regenerated video signal and the regenerated composite video signal for presenting a phase modulated converted composite video signal of a horizontal synchronization signal in response to the compensation signal; means for phase modulating a horizontal synchronization signal of a composite video signal; means for adjusting the amplitude and phase of the compensation signal provided in the compensation generation means;
A pseudo-composite video signal comprising vertical and horizontal synchronization signals and a mark signal located at a predetermined phase position in a video signal region, wherein the horizontal synchronization signal of the pseudo-composite video signal is shifted compared to that of the television system. and this pseudo-composite video signal is used in place of the reproduced composite video signal, whereby the mark signals in the pseudo-composite video signal are means for generating a pseudo-composite video signal that enables adjustment of the adjustment means while observing a sign; means for generating, voltage controlled oscillator means for generating the horizontal synchronizing signal of the pseudo composite video signal, and means coupled to the vertical synchronizing signal generating means for generating the phase shift of the horizontal synchronizing signal of the pseudo composite video signal. means for controlling said voltage controlled oscillation means to generate said mark signal in response to an output from said voltage controlled oscillation means; and said vertical synchronization signal for presenting said pseudo composite video signal; A jitter correction device for a video playback device, comprising means for mixing the horizontal synchronization signal and the mark signal.