JPS61290872A - Video signal reproducing device - Google Patents

Abstract

PURPOSE:To prevent a screen from flickering and to make a synchronization follow quickly when reproducing a new track by providing a means for muting a video signal reproduced when a head moves to other track and always applying a composite synchronizing signal to a video signal outputted through the muting means. CONSTITUTION:When executing a reproduction, a switch SW1 is connected to a reproducing amplifier 7 side by a control signal S-2 from a system controller 15 and video signal S-4 reproduced by a magnetic head 5 is inputted to an encoder 9 through the reproducing amplifier 7 and a demodulator 8. In the encoder 9, an SCS-8 from a synchronizing system circuit 14 is received, a processing for encoding a chroma signal is executed and also a color burst signal is applied to a demodulated video signal by a BFS-9 outputted from the system controller 15. In the same way, character signal S-5 outputted from the system controller 15 is multiplexed to the video signal. It is executed in order to realize that for instance, a data, time, a track, etc. can be displayed on a part of the screen.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal reproducing device that reproduces a video signal from a recording medium using a head.

[Conventional technology]

Hereinafter, in this specification, this type of device is constructed by forming a plurality of concentric tracks on a magnetic sheet, recording a video signal for one field on each track, and repeatedly reproducing the video signal. Example f of a device for obtaining still images
I will explain it.

FIG. 2 is a block diagram showing an example of a conventional video signal recording and reproducing device. In FIG. 1, 1 is an input terminal, 2 is a decoder, 3 is a modulator, 4 is an amplifier, 5 is a magnetic head, and 6 is a magnetic・Ki sheet, 7 is amplifier, 8 is demodulator, 10 is monitor,
11 is the head drive unit, 12 is the sir? system, 13 is a synchronization separation unit, 14 is a synchronization system, 15! system controller, 16
4d17 remote control switch, 17 is the light receiving part. In addition, SW is a switch, S-1 is a video signal, and S-1 is a video signal.
-2 is a control signal, S-4 is a reproduced video signal, 5-1
0 is a free run control signal, 5-12 is a vertical synchronization signal (
(hereinafter referred to as V5ync) and horizontal synchronization signal (hereinafter referred to as H8y
5-13 is a 60Hz vertical drive glus (hereinafter referred to as VD) obtained from the video signal,
5-14 is the magnetic sheet 60 rotation detection/mother pulse (hereinafter PG
pulse).

In the above configuration, the video signal S-1 passes through the decoder 2, the modulator 3, the recording amplifier 4, and the switch SWi.
The information is recorded on the magnetic sheet 6 by the magnetic head 5. Also, during playback, the control signal S-2 output from the system controller 15 causes the switch SW! is connected to the reproduction amplifier 7 side, and the video signal S-4 reproduced by the magnetic head 5 passes through the reproduction amplifier f7 and the demodulator 8.
It is input to the monitor 10.

As is clear from the above description, in conventional video signal reproducing devices, for example, when a head is reproducing a video signal on one circular track, the reproducing head is sent to another track for reproduction. When doing so, the head passes over the tracks between them, so unrelated images appear continuously on the screen during that time. Furthermore, if there is a negative band between tracks where nothing is recorded, no signal will be output intermittently.

[Problem that the invention seeks to solve]

The conventional video signal reproducing apparatus as described above has a problem in that the screen flickers and is very difficult to see. Also,
Even when sending the head to an adjacent track, the screen will be disrupted for a moment before the next track is played.

Furthermore, when the head passes over the guard band for the video playback device and monitor, no signal is input, and then when the head comes over the track where video information is recorded. It is necessary to synchronize with the recorded video information, but since there was no signal until just before that, a high-speed PLL circuit is required to synchronize quickly, which increases the cost of playback circuits, monitors, etc. At the same time, there is a problem in that the circuit scale increases.

This invention was made to solve these problems, and it provides a video signal that prevents the screen from flickering even when the head is moved to a track, and also allows the synchronization to quickly follow when a new track is played. The purpose is to obtain a playback device.

[Means for solving problems]

The video reproducing apparatus according to the present invention includes a means for muting the reproduced video signal when the head moves to another track, and a composite synchronization signal to the video signal outputted through the muting means. It is configured so that it is always added.

[Effect]

In this invention, when the spatula P moves to another track, the video signal is muted to prevent the output screen from flickering, and the composite synchronization signal is still being sent during this time, so even after the track is moved, the video signal is muted. Can be synchronized.

〔Example〕

FIG. 1 is a block diagram of one embodiment of the present invention, and the second
The same symbols as in the figure indicate the same things, 9 is an encoder,
S-3 is a control signal, S-5 is a character signal, S-6 is an output video signal, S-7 is a composite synchronization signal (hereinafter referred to as CS sync), s-8 is a color subcarrier (hereinafter referred to as C), S-9
is burst flag/mother Russ (hereinafter referred to as BF), 8w2
is a switch.

In the video playback device configured as described above, recording is the same as the conventional example shown in FIG. 2, but playback is performed using the control signal S-2 from the system controller 15.
The switch SWl is connected to the reproduction amplifier 7 side, and the video signal S-4 reproduced by the magnetic head 5 is inputted to the encoder 9 via the reproduction amplifier 7 and the demodulator 8.

The encoder 9 receives 5cs-s from the synchronous circuit 14 and performs processing to encode the chroma signal. Also,
BF S-9 output from system controller 15
A color burst signal is added to the demodulated video signal. Similarly, the character signal S-5 output from the system controller 15 is multiplexed on the video signal. This is for displaying, for example, date, time, track, etc. on a part of the screen. Furthermore, by multiplexing the C3yncS-7 output from the synchronization circuit 14, a video signal S-6 conforming to the NTSC signal, for example, is generated.
and send it to the monitor 10.

The input video signal S-1 during recording and the reproduced output video signal S-6 during playback are input to the synchronization separator 13.
11, the synchronization system 14 synchronously generates various timing signals. Furthermore, the synchronization system 14 also has a free run state due to an internal oscillator. This synchronization system 14 sends a signal 5-12 including V5ync and )(5ync to the system controller 15,
The free run control signal 5-1 is sent from the CPU 15.
Receive 0. Then, VD 5-13 is input to the servo system 12, and the servo system 12 rotates the magnetic sheet 6 in synchronization with this VDS-13. The head drive section 11 is, for example, a step motor, and drives the magnetic head 5. This is controlled by a control pulse φ8 from the CPU 15.

Now, when the user wants to advance a track and sends a signal to the light receiving section 17 using the remote control switch 16, the light receiving section 17 sends a pulse φ.

and is sent to the system controller 15.

This is, for example, from the first track to the second track from the inner diameter side.
Assuming that the signal sends the magnetic head 5 to the 0th track, the CPU 15 outputs a control signal S-3 for connecting the switch SW2 to the GND side. Furthermore, although the reproduced video signal S-4 is no longer input to the encoder 9, the 5cs-s and csyncS-72 character signals S
-5, BFS-9 is input, so C3yncS
Since the newly added output video signal S-6 is output only for -7 and the burst signal, a black screen appears on the monitor 10, for example.

Here, if the connection of the switch SW2 is changed before the number H of VsyncO, muting can be performed on the monitor 10, and at the same time, the signal φ is sent to the head drive section 11. For example, if it is possible to send 1 track with 10 pulses, then by sending 190) pulses, it is possible to move from 1 track to 20 tracks.

When the magnetic head reaches the 20th track, Vsyn
When the switch SW2 is switched aO number H before, the video information on the 20th track appears on the monitor 10. Here, the synchronization system 14 attempts to synchronize with the reproduced video signal S-4, but since there is no reproduced video signal S-4 during muting, the control signal 5-10 causes it to be in a free run state. Then, the C3yncS-7 is on monitor 1.
It was sent to 0. Here, the servo system 12 is VDS
-13 and pQ/#Rus5- sent from the rotating sheet
Since the phase with 14 is matched, V in the free running state
5ync and V 5yn of the reproduced video signal S-4.
Since there is no significant difference between the two tracks, the synchronization will not be significantly out of sync when the free running state of miniting is shifted to playback of a new track.

In addition, even when playing back adjacent tracks one after another at high speed, muting can be performed while the no-signal portion between tracks is being played, which eliminates screen disturbances and Since the synchronization catches up quickly, there is less synchronization disturbance during playback, making it possible to perform frame-by-frame playback that is very easy to view.

Note that the recording medium used in the above embodiments is not limited to magnetic disks; it is also possible to use optical disks as long as a corresponding head section is provided. The department is not just one dopando,
It can be used for unrecorded tracks, and can also be operated by wire instead of a remote control. Furthermore, during muting, it is not limited to black, but it is also possible to output gray, white, etc., and muting may not be necessary for reasons such as search, so in that case, it is recommended that the user be able to change the output using a switch. good. Furthermore, character signals, BF
, SC can of course be muted, and the number of heads may be any number, and the timing for switching switch SW2 during track forwarding does not have to be V5yncO number H before.

〔Effect of the invention〕

As explained above, the present invention includes a means for muting a reproduced video signal by providing a muting circuit when a track is sent to move the head to another track;
Since a means for adding a composite synchronization signal to the video signal outputted via the muting means is provided, it is possible to eliminate screen flickering and disturbances during track forwarding, and to ensure synchronization when playing a new track. This has the advantage that there is no large deviation and there is no need for a high-speed PLL circuit for both the reproduction circuit and the monitor.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional video signal reproducing apparatus. In the figure, 1 is an input terminal, 2 is a decoder, 3 is a modulator, 4 is an amplifier, 5 is a magnetic head, 6 is a magnetic sheet, 7 is an amplifier, 8 is a demodulator, 9 is an encoder, 10 is a monitor,
11 is the head drive unit, 12 is the sir? 13 is a synchronous separation unit, 14 is a synchronous system circuit, 15H system controller,
16 is a remote control switch, and 17 is a light receiving section. In addition, swt and sw2 are switches, S-1 is a video signal,
S-2 and S-3 are control signals, S-4 is a reproduced video signal, S-5 is a character signal, S-6 is an output video signal, S-7
is C3ync, S-8ke SC, S-9 is BF. 5-10 is a free run control signal, 5-11 is 5ync
. 5-12 is a signal including VSyne and H8ync, 5-1
3 is VD, and 5-14 is PG mother Rus.

Claims (1)

[Claims] In a video signal reproducing device that reproduces a video signal using a head, when moving the head to another track, a means for muting the reproduced video signal and a composite synchronization signal are outputted via the muting means. 1. A video signal reproducing device characterized by comprising means for always adding information to a video signal.