JPS61233467A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate necessity of removing a video signal component using a filter, and prevent distortion of address signal waveform by not recording video signal component in the address signal part on a disk, and inserting delayed precedent video signals in lacking part of video signals at the time of reproducing. CONSTITUTION:Signals reproduced from a disk 4 are supplied to a drop-out detector 6, and lack of signal is detected, and the detection signal is supplied to an address gate circuit 7. The gated address signal is supplied to an address detector 8, and address information is detected and outputted to a terminal 9. In this case, as signals are not recorded in the address signal part, it is regarded as drop-out and compensated. A drop-out compensating circuit 11 switches a signal obtained by delaying the drop-out compensated signal by horizontal scanning period of video signals by a 1H delay line 13 and a signal from an FM demodulator 10 using a switch 12 according to output signals of the drop-out detector 6.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video signal recording and reproducing device for recording and reproducing video signals on a disk-shaped recording medium (hereinafter referred to as a disk) on which an address signal has been formed in advance. It is.

Conventional technology Generally, when it is necessary to record a continuous signal such as a video signal on a disk-shaped recording medium on which guide grooves and address signals have been formed in advance, the video signal is also overwritten on the address signal. things are being done. In this case, during playback, as shown in FIG. The demodulated video signal is output. Further, the filter 18 removes the video signal component from the signal reproduced from the disc 4, and the remaining component is supplied to the address detector 8, which outputs address information to the terminal 9.

Problems to be Solved by the Invention However, when the video signal component is superimposed on the address signal in this way, the frequency band occupied by the address signal is wide and overlaps with the frequency band occupied by the video signal component. Therefore, the address signal component cannot be completely removed by the filter 16, and the address signal component is mixed into the video signal component. Therefore, when this video signal component is demodulated by the video signal demodulator 10, noise due to the address signal occurs in the output video signal. This noise not only interferes with video information, but also interferes with synchronization signals, causing a problem in that it causes synchronization disorder on the screen.

Furthermore, since a portion of the address signal component is lost when the video signal component is removed by the filter 18, there is a problem in that the address signal waveform is distorted and the address detector 8 is more likely to malfunction.

The present invention is intended to solve these conventional problems, and aims to provide a video signal recording and reproducing device that can remove noise from video signals and stably detect address signals.

Means for Solving the Problems In the video signal recording and reproducing apparatus of the present invention, no video signal component is recorded in the address signal portion on the disk, and during playback, the previous video signal is recorded in the missing portion of the video signal. It is configured to insert a delayed video signal.

According to the video signal recording and reproducing device of the present invention, since the video signal component is not recorded by overwriting the address signal portion, there is no need to remove the video signal component using a filter, and the address signal waveform is not distorted. Addresses can be detected stably.

Then, since the video signal component missing in the address signal portion is demodulated and then inserted with a delayed video signal recorded in a portion other than the address signal portion, it is possible to prevent any interference noise caused by the address signal from occurring.

Embodiment Hereinafter, a video signal recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a recording part in an apparatus according to an embodiment of the present invention. As shown in the figure, a video signal input to a terminal 1 is transmitted to an FM modulator 2
The signal is frequency modulated and supplied to the address mute circuit 3. This address mute circuit 3 is connected to the disc 4 to be recorded.
A signal indicating the timing of the address signal formed in the guide groove of the address mute pulse generator 5 is supplied to the address mute pulse generator 9.
The video signal component is recorded on the recording disc 4 by removing the signal in the period corresponding to the address signal portion of the disc 4 from among the frequency modulated video signal components.

FIG. 2 is a block diagram of a reproduction section in an apparatus according to an embodiment of the present invention. As shown in the figure, the signal reproduced from the disc 4 is supplied to a dropout detector 6 to detect signal loss in the reproduced signal, and this detection signal is supplied to an address gate circuit 7. Further, the signal reproduced from the disc 4 is supplied to the address gate circuit 7, and the address signal portion where no video signal component is recorded is gated and output. The gated address signal is supplied to an address detector 8 to detect address information and output to a terminal 9.

Furthermore, the signal reproduced from the disc is sent to an FM demodulator 1o.
The address signal part of this video signal becomes noise because no signal is recorded, and this video signal is supplied to the dropout compensation circuit 11.
The address signal portion is considered to be a dropout and compensated for.

Therefore, a video signal from which noise has been removed is output to the terminal 14.

Further, the dropout compensation circuit 11 transfers the dropout compensated signal to the 1H delay line 13 as shown in FIG.
This is achieved by switching between a signal delayed by a horizontal scanning period (hereinafter referred to as 1H) of the video signal and a signal from the FM demodulator 1o using a switch 12 according to the output signal of the dropout detector 6. I can do it.

In this case, if the signal loss period extends over 1H, the demodulated video signal will repeatedly pass through the 1H delay line 13, and the video signal output from the terminal 14 will deteriorate, so the signal loss period will be within 1H. It is desirable that the address signal period be within 1H.

In addition, if the address signal period cannot be kept within 1H or if you want to form multiple address signals in succession, the period of each signal should be within 1H, and if they are formed at least 1H apart, then 1H before the address signal is By ensuring that the video signal component is always recorded, deterioration of the video signal in the dropout compensation circuit 11 can be minimized.

Effects of the Invention As described above, according to the video signal recording and reproducing apparatus of the present invention,
Since the video signal component is not recorded in the address signal portion of the disk, the address signal can be separated from the video signal component by a gate circuit, etc., and the waveform is not distorted by filters and is stable. can be detected.

In addition, the signal loss portion of the video signal can be completely compensated for using the video signal delayed by a dropout compensation circuit, etc., so unnecessary noise is not generated, which is extremely advantageous in practice. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the recording section of a video signal recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram of its reproducing section, and FIG. 3 is a block diagram of the reproducing section of a conventional video signal recording and reproducing apparatus. It is a block diagram. 2...FM modulator, 3...Address mute circuit, 4...Disk, 6...Address mute pulse generator, 6...・Dropout detector, 7...Address gate circuit, 8...
・Address detector, 1o...FM demodulator, 11...
...Dropout compensation circuit.

Claims (3)

[Claims] (1) A video signal component occupying a predetermined frequency band is recorded on a disc-shaped recording medium in which a guide groove is formed in advance and an address signal is formed by changing a part of the guide groove. A device for reproducing,
The video signal component is not recorded in the address signal portion, and during playback, a signal obtained by delaying the previously recorded video signal by a predetermined delay time is inserted into this unrecorded video signal section. A video signal recording and reproducing device characterized by: (2) The video signal recording and reproducing apparatus according to claim 1, wherein the period during which the video signal component is not recorded is shorter than the horizontal scanning period of the video signal to be recorded. (3) A video signal according to claim 1, characterized in that there are a plurality of parts where no video signal component is recorded, and the interval between the plurality of parts is longer than the horizontal scanning period of the video signal to be recorded. Recording and playback device.