JPH0423878B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION For example, it is conceivable that a microcomputer and a video disk player may be combined to provide guidance on sightseeing spots.

That is, in FIG. 1, numeral 1 indicates a microcomputer, from which standard three primary color signals R, G, and B are output, and these signals R to B are supplied to the switcher 4. Reference numeral 2 indicates, for example, a laser-type video disc player. A standard composite color video signal is taken out from the player 2, and this signal is supplied to an NTSC decoder 3, which then receives the standard three primary color signals R to B and the composite color video signal. The synchronizing pulse _Ps is taken out and these signals R to B are supplied to the switcher 4. The switcher 4 is controlled by a control signal S _w from the computer 1 , and the two sets of signals R to B from the computer 1 and decoder 3 are switched or mixed and supplied to the color monitor 5 . A synchronizing pulse P _s from is supplied to the monitor 5.

At this time, the synchronizing pulse P _s and the color subcarrier S _c are supplied from the computer 1 to the player 2, and the video output of the computer 1 and the video output of the player 2 are synchronized.

In this way, by inputting the conditions indicated by the customer into the computer 1, data such as costs are outputted from the computer 1 and displayed on the monitor 5.

Further, the player 2 is controlled by the computer 1 to reproduce a screen of the scenery of the destination, and this is reproduced as an image on the monitor 5, superimposed on the data image from the computer 1, for example.

By combining the computer 1 and the player 2 in this manner, various guidance services and the like can be realized.

However, in this case, when player 2 performs variable speed playback such as slow playback or still playback,
The playback screen of monitor 5 may appear for the following reasons.
This results in a jitter of 140 ns.

That is, in a laser type video disc, a recording track is formed in a spiral shape, and in the standard mode, one frame of a color video signal is recorded in one round of the recording track. Therefore, in player 2, during variable speed playback, for example during still playback, the scanning position of the playback head (laser light source and light receiving element) is returned by one track every time the video disk rotates once, thereby producing one frame. The unit is still being regenerated. In other words, a still reproduced image is obtained by repeatedly reproducing one frame of color video signal.

However, in the case of the NTSC system, the color subcarrier frequency f _sc is f _sc =455/2f _h =455/2・525/2・f _v =455×525×1/4×f _v f _h : Horizontal frequency f _v : Vertical frequency, that is, as shown in FIG. 2A, the phase of the color subcarrier S _c returns to the original position every 2 frames (4 fields) with respect to the synchronization pulse P _s , Each frame is shifted by 180 degrees.

Therefore, in the video disc player 2,
For example, when performing still playback, the reproduced color video signal is a repetition of one frame of the signal, so the phase of the carrier color signal changes from frame to frame as shown in Figure 2B. The phase shifts by 180°.

Therefore, in the video disc player 2, during still playback, the phase of the synchronizing pulse P _s is shifted by 180 degrees, that is, 140 ns for each frame, so that the phase of the carrier color signal with respect to the synchronizing pulse P _s The relationship shown in Figure 2A is established.

In other words, during still playback, the temporal position of the synchronization pulse P _s deviates from its original position by 140 ns for each frame.

Therefore, when the monitor 5 is horizontally and vertically deflected by such a synchronization pulse P _s , when a video signal from the computer 1 is supplied to the monitor 5, the image by the video signal from the computer 1 is will result in a jitter of 140ns.

In the case of variable-speed playback other than still playback, the phase of the synchronization pulse P _s is similarly shifted by 140n seconds at a cycle corresponding to the variable-speed playback mode, so the same jitter is generated on the output screen of computer 1. will occur.

This invention attempts to solve these problems.

Let's explain one example below.

In FIG. 3, the signal R from the computer 1
~B is supplied to the switcher 4 through the delay circuit 6, and a control signal _Sd for the delay time of the delay circuit 6 is supplied from the player 2, and the delay time is controlled to 0 or 140 ns. This signal _Sd is a signal that controls the track position of the playback head during variable speed playback of a video disc. In other words, in the case of still playback, when the video disc completes one rotation,
It can be formed from a signal that returns the playback head to its original track, which corresponds to the synchronization pulse P _s .
This is the same signal that indicates whether or not a 140 ns shift has been performed, and as described above, the synchronization pulse P _s is
The frame period is delayed by 140 ns, and the delay time of the delay circuit 6 is controlled to 140 ns.

Therefore, according to such a configuration, player 2
During variable speed reproduction, in order to maintain the continuity of the phase of the carrier color signal, _{the signal S d causes} the delay circuit 6 to
Since the delay time is 140 ns and the delay time is 0 in other frame periods, the signals R to B supplied from the computer 1 to the monitor 5 via the switch 4 are supplied from the player 2 to the monitor 5 via the decoder 3. 140n for synchronization pulse P _s
There will be no difference in seconds.

Therefore, when the player 2 performs variable speed reproduction, no jitter occurs on the output screen of the computer 1.

FIG. 4 shows an example of the delay circuit 6. That is,
Q ₁ and Q ₂ are emitter follower transistors for the buffer, 6D is an LC delay circuit with a delay time of 140 ns, and 6W is a switch circuit, and this switch circuit 6W is switched by the signal S _d to delay the delay circuit 6. The time is controlled to 0 or 140ns.

In the example shown in FIG. 5, the synchronizing pulse P _s from the computer 1 is supplied to a delay circuit 6S which is controlled in the same way as the delay circuit 6, and its output is sent to the monitor 5.
This is the case when it is supplied to

Furthermore, in the example shown in FIG.
The composite color video _signal from
P _s and the synchronization pulse P _s from the computer 1 are compared in phase in the phase comparison circuit 8, and the comparison output is supplied as a signal S _d to the delay circuit 6. When there is a phase difference between the two synchronization pulses P _s , the delay A delay of circuit 6 is performed.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 4 are diagrams for explaining this invention, and FIG. 3, FIG. 5, and FIG. 6 are system diagrams of an example of this invention. 1 is a microcomputer, 2 is a video disk player, 4 is a switch, 5 is a monitor, 6R
~6B is a delay circuit.

Claims (1)

[Claims] 1 A video disc playback device that is externally synchronized and capable of variable-speed playback, and that corrects the phase of the synchronization pulse so that continuity of the carrier color signal is obtained during variable-speed playback, and a color television that serves as a reference. A computer that outputs a signal is used to apply external synchronization by supplying the synchronization pulse and color subcarrier of the color television signal from the reference computer as an external synchronization input to the video disc playback device, and outputs the synchronization pulse as well. The phase of the color TV signal from the reference computer is changed by the amount of correction of the phase of the synchronization pulse by the signal indicating that the phase of the color TV signal from the computer has been corrected, and the color TV signal from the computer whose phase has been changed is A color video signal playback device which switches or mixes the playback output of the video disc playback device and supplies the signal to a color monitor for display.