JPS5881396A - Video disk reproducing device - Google Patents

Abstract

PURPOSE:To prevent a reproduced signal from deteriorating in quality, and to simplify circuit constitution by mixing a (R-Y) component having doubled amplitude with a reproduced composite color video signal without separation into a luminance and a chrominance signal. CONSTITUTION:A (R-Y) component having doubled amplitude is led out of an adder 9 and also passed through a band-pass filter 10 to eliminate a luminance signal component, and the resulting signal is supplied to an inverter 11. In a frame where a switch circuit 12 is turned on during a track jump, the chrominance signal from the inverter 11 is supplied to an adder 6 together with a color video signal which is inputted from an input terminal 3 and put in phase by a delay circuit 5. At an output terminal 4, a PAL composite color video signal having a chrominance signal inverting the color subcarrier of the (R-Y) component in phase at every 1H interval even in case of a track jump and a burst signal varying in phase at every 1H interval corresponding to it appears.

Description

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

As shown in FIG. 1, a track 2 is formed in a spiral shape on a video disc 1, and seven frames of a color video signal are recorded as seven revolutions of track 2 from point P to point Q. be done. During recording, the carrier signal is modulated using a composite color video signal consisting of a luminance signal, a carrier color signal, etc. as a modulation signal. As the video disc 1, there are known optical discs, capacitive discs, etc. in which the signal surface is a reflective surface and has a geometric pattern according to the recording signal. Still reproduction can be performed by repeatedly reproducing seven rounds from track point 20P to Q point as described above. The playback head starts playing from point P and starts from point Q.
When the point is reached, the track jump is instantaneously jumped again to the point P, and this track juffing period is usually selected within the vertical blanking period. Furthermore, not only still playback but also high-speed playback can be achieved by performing track jumps to omit fields every predetermined number of 0 fields.

By the way, when a PAL system composite color video signal is recorded as track 2, when the above-mentioned track jump is performed, a problem occurs regarding the demodulation of the color signal.

As shown in Figure 1 AlIC and Figure 1 BK, in the PAL system, the color subcarrier of the (RY) component is inverted every IH (/horizontal period), and the phase of the burst signal corresponds to this. It also changes from IH to IH. In addition, if the number of lines in the / frame is an odd number of 623, as shown in Figure 3 and Figure B, the (R-Y) of the horizontal period of the corresponding number between the I frame and the next frame. The color subcarriers of the components are inverted and are in the nine-way range. FIG. 3 shows the equalization pulse period, vertical synchronization period, etc. of the vertical blanking period. The video disc 1 described above has a track pattern in which horizontal periods of corresponding numbers of each frame are arranged in the radial direction, so when jumping to an adjacent track, the IH of the color subcarrier of the (RY) component every y
The regularity of the transfer relationship is lost. Therefore, the reproduced image at the time of track jump is distorted. The color demodulation circuit of the pAIJ method is configured to discriminate the phase of the subcarrier and control the phase of the subcarrier for demodulation so that it corresponds to the phase of the subcarrier, but it has a time constant that is large enough to generate a discrimination output. As a result, the above-mentioned conditions such as disturbed hue and lack of color during the track jump extend to approximately T of both reproduced images.

One way to solve this problem during track jumping is to separate the reproduced PAL color video signal into a luminance signal and a carrier chrominance signal, and further improve the regularity of the phase inversion relationship of the carrier chrominance signals. It is conceivable to perform processing that does not occur even during a track jump, and then add the signal to the luminance signal and output the result. However, even though the carrier signal is modulated with a composite signal including the luminance signal and carrier chrominance signal, it is unreasonable to process the luminance signal and carrier chrominance signal separately in the reproduction system. Furthermore, there is a risk that the configuration on the playback side will become complicated and the quality of the signal will deteriorate.

(9) As another method, it is conceivable to perform recording such that the recording position is shifted in adjacent tracks by IH, but this has the problem that the configuration of the recording system becomes complicated.

In consideration of the above points, the present invention provides (
This is to prevent the regularity of the inversion of the color subcarrier of the carrier color signal of the RY) component from being lost.

An embodiment of the present invention will be described below with reference to FIGS.

In the figure, a PAL composite color video signal reproduced from a video disc 1 and subjected to FM demodulation is supplied to an input terminal indicated by 3, and is supplied to one side of an adder 6 via a delay line 5 for phase adjustment. is supplied to the input terminal of , from which the output terminal 4 is derived. FIG. 3 shows a carrier color signal which is an input color video signal Kt. ,. Ka, - kadeya ya v
The change in iH units is shown.

Further, the color video signal from the input terminal 3 is supplied to one input terminal of the adder 9 and is also supplied to the other input terminal of the adder 9 via the K, IH delay line T and the inverter 8. Here, the total delay time of the IH delay line 7 and the inverter 8 is (284Xλ6°) (where λ8o is the period of the color subcarrier). In the PAL system, the relationship is fac = (284-7) rh + A (where fac is the frequency of the color subcarrier and fh is the line frequency), (IH = 283,7516λ8
゜), IH is not an integral multiple of λ8c. Therefore, if the delay amount is strictly @KIH, the carrier color signal for (B-Y)6 will not be completely removed from the output of the adder 9, so as mentioned above, 2g'1 times λ8c .

FIG. 3B shows the carrier color signal 8! being output from the IH delay line 7! It shows a change in IH units of the color subcarrier of , and is converted into a carrier color signal i- as shown in FIG. In the adder 9, the carrier color signals 81 (person in Figure 3) and - (C in Figure 5) are added, so the carrier color signals of the K and (B-Y) components are removed as shown in Figure 5DK. Then, the carrier color signal S3 of the (RY) component having twice the amplitude is taken out from the adder 9. When the output of the adder s is passed through a bandpass filter 10 with a pass characteristic centered on the subcarrier frequency fsc, the luminance signal component is removed by K, and the filter is further supplied to an inverter 11.

The total delay time caused by the band bus fiber kfi 10 and the inverter 11 is made equal to the delay time of the delay line 5. At the output of this inverter 11, a carrier color signal 83 (not shown) having a phase opposite to that shown in FIG. This switch circuit 12 is turned on and off every frame by a control signal obtained from the output of the 7-resolution 70 tube 13. Aritubu flop 13 is
The output is inverted every time the input signal is supplied, and the pulse generated every time a track jump is sent to terminal 1.
4 to 7 lip-flops 13. At the same time, during normal reproduction operation, the output for keeping the switch circuit 12 off is generated from the 7-rip 70 tube 13.

In the 7th frame in which the switch circuit 12 is on at the time of track jump, the carrier color signal 83 from the inverter 11 is added together with the color video signal from the input terminal 3 whose phase is matched by the delay circuit 5.
K is supplied. Therefore, at the output terminal 4 of the adder 6,
As shown in Figure 3 EK, the original O phase is inverted (R-Y
) component color subcarrier is obtained. Therefore, the regularity of the phase inversion of the (R−Y)m subcarriers is not impaired. Also, when the next track jump occurs, that firefly's /
In the frame, the output of the Aritz flop circuit 13 is inverted, and the -switch circuit 12 is turned off (tt). Furthermore, when the next track jump occurs, the switch circuit 12 is turned on again in the next seven frames. In this 5, 12 switch circuits, track jump and k, from on to off.

The state changes from off to on. Due to this operation, even if there is a track jump at the output terminal 4,
The color subcarrier of the K(R-Y) component is necessarily phase-inverted for each IH, and the phase of the carrier color signal corresponding to this is inverted for each IH.
A PAL composite color video signal containing a burst signal that changes every time is obtained.

FIG. 6 shows another embodiment of the invention. In this example,
Connect the bandpass filter 10 to the input terminal 3,
After separating the carrier chrominance signals, it is possible to form the (R-Y) component of single amplitude. The other configurations are the same as those of the above-mentioned embodiment.

In addition, all inverters 8 are removed from the configuration shown in FIGS. q and 6, and the IHM is expanded! 110 slow amount (284,5
λ8°). Furthermore, it is also possible to remove the inverter 11 in the configurations shown in FIGS.

As can be understood from the description of the embodiments above, this originating BA
According to VC, even if you do a truck jump and make a lot of money, (
Phase inversion of color subcarrier of R-Y) component owiv
It is possible to prevent the loss of tackiness. (9) In this invention, the (R-y) component of one times the amplitude is synthesized into the reproduced composite color video signal without separating the luminance signal and the carrier color signal, so that the circuit configuration on the reproduction side can be simplified. (complicated), there is an advantage that the quality of the reproduced signal does not deteriorate.

Furthermore, since the recording pattern may be one in which horizontal sections of corresponding numbers are lined up in the radial direction of the disk, the configuration on the recording side does not become complicated.

[Brief explanation of the drawing]

FIG. 7 is a plan view used to explain a video disc to which the present invention can be applied; FIG. A block diagram of one embodiment of the present invention and a vector diagram used to explain its operation, and FIG. 6 is a block diagram of another embodiment of the present invention. 1...Video disc, 2...
・・・・・・・・・Track, 3・・・－・・・・・・
・Input terminal, 4...Output terminal, 8
, 11... Inverter, 7...
・・・・・・・・・IH delay line. Agent Tadashi Sugiura Figure 3

Claims (1)

[Claims] A PAL composite color video signal is used as a modulation signal and N-modulated as a carrier signal, and nine signals are recorded on the video disk, and during playback, the playback head moves in the radial direction of the video disk, causing a $111') rack. In a video disc playback device that performs a track jump operation, the carrier color signal of the (R-Y) component is separated from the reproduced composite color video signal of the PM method after demodulation, and the carrier color signal of the (R-Y) component is divided into a switch circuit that operates during the track jump operation, and a carrier color signal of the (R-Y) component with an amplitude a times the amplitude above the circle, which is synthesized with the reproduced composite color video signal through the switch circuit. (R
A video disk reproducing apparatus comprising: - a synthesis circuit for inverting the phase of a carrier color signal of the Y) component.