JPH0326077A - Video floppy disk recording and playback device - Google Patents

Abstract

PURPOSE:To avoid production of skew by controlling the changeover of a field signal recorded on a magnetic recording medium in response to odd even information of a current reproducing track and a moving track at track movement and a signal retarded by a 1/2 horizontal synchronizing period and the head changeover. CONSTITUTION:The device is provided with a storage circuit 21 storing odd/even information representing whether a video signal recorded on each track of a magnetic recording medium 15 is a video signal of an odd number field or of an even number field and a changeover control circuit 22 controlling the head changeover and a changeover of a field signal recorded on the magnetic recording medium 15 and a signal retarded by a 1/2 horizontal synchronizing period from the odd/even information of a track before movement and the odd/even information of a track after the movement in the case of moving the track during reproduction. Thus, either of the odd number field or the even number field of the video signal is not reproduced consecutively for 2 consecutive vertical synchronizing periods. Thus, skew on the upper part of the screen is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus capable of moving tracks without causing skew even if the tracks are moved during playback of a video signal recorded on a video floppy.

BACKGROUND OF THE INVENTION FIG. 2 shows a block diagram of a conventional video floppy disk recording and reproducing apparatus. 1 is a recorded video signal processing circuit that performs signal processing of the video signal input to the video input terminal; 2 is an FM modulation circuit that performs FM modulation on the video signal processed by the recorded video signal processing circuit 1; 3 is an FM modulation circuit 2
4 is a video floppy disk (hereinafter referred to as video floppy).
Reference numeral 16 denotes a reproduction amplification circuit for amplifying the reproduced FM signal that is surprised up by the magnetic head 16, 6 an FM demodulation circuit that demodulates the reproduction amplified signal, 6 a reproduction video signal processing circuit that performs signal processing of the FM demodulated signal, and 7 iD from the reproduced amplified signal
A field/frame discriminating circuit for discriminating signals, 7 L' A field/frame discriminating circuit for discriminating signals, and 8 delaying the video signal processed by the reproduced video signal processing circuit 6 by 3 AH (H indicates one horizontal synchronization period). 9 is a changeover switch for switching between the output of the reproduction video signal processing circuit 6 and the output of the %H delay circuit 8; 10 is a head changeover switch for switching between the inside and outside measurement of the magnetic head 1e; 11 is a Recording/playback switch for switching between recording and playback, 12 magnetic head 1
6 is a step motor for moving the video floppy 16 in the radial direction, 13 is a step motor drive circuit for driving the step motor 12, and 14 is a step motor drive circuit for driving the step motor 12 to move the magnetic head 1e in the radial direction of the video floppy 15. A moving head moving mechanism, 1T is a spindle motor that rotates the video floppy 15, 18 is a motor control circuit that controls the rotation and stopping of the spindle motor, and 19 is a drive command for the step motor 12 and rotation and stopping of the spindle motor 17. This is a system control circuit that outputs commands, etc.

The operation of the conventional video floppy disk recording and reproducing apparatus will be explained below with reference to FIG.

When recording a video signal, switch the recording/playback switch 11 to the (REC) side and switch the system control circuit 1.
A recording gate pulse is input from 9 to the recording amplifier circuit 3, the signal is processed by the recording video signal processing circuit 1, and the FM modulation circuit 2 inputs the recording gate pulse to the recording amplifier circuit 3.
The signal is M-modulated and amplified by the same path 3, and a recording current is passed through the magnetic head 16 to record on the video floppy 16.

When reproducing, the recording/reproducing selector switch 11 is switched to the PB side, the FM signal recorded on the video floppy 16 is boosted by the magnetic head 1e, the FM signal is amplified by the reproducing amplifier circuit 4, and the amplified FM signal is output by the FM demodulating circuit. The signal is demodulated, processed by the playback video signal processing circuit 6, and output from the video output terminal for playback. At this time, from the FM signal amplified by the regenerative amplifier circuit 4, the 7 elt/frame discriminating circuit discriminates the field/7 frame, and sends the discrimination signal to the system control circuit 1.
9, and when determining the field, set changeover switch 9 to 1.
A every vertical synchronization period. During frame discrimination, the head changeover switch 10 is switched between (inner) and (outer) every vertical synchronization period.

When moving from the frame playback track, move the head selector switch 10 every vertical synchronization period to move the track by one track, and when move from the field playback track, switch the head selector switch 9 every vertical synchronization period. Move while switching.

Problems to be Solved by the Invention However, in the above structure, in order to move the head by one point when pseudo frame playback or head switching is performed, pseudo frame playback is performed between two adjacent tracks of odd and even fields. If you move one track in one vertical synchronization period, if you move to an even field recording track during playback of an odd field recording track, when you play the even field recording track, the same field as the field that was playing the odd field recording track will be played continuously. Since the same field is continuously reproduced during two vertical synchronization periods, there is a problem in that skew occurs when reproduced on a TV screen.

The present invention stores odd-even information indicating whether a video signal recorded on each track of a magnetic recording medium is an odd field video signal or an even field video signal, and when moving tracks, the odd-even information of the currently played track and the track to be moved are stored. Accordingly, switching between the field signal recorded on the magnetic recording medium and a signal delayed by 1/2 horizontal synchronization period and head switching are controlled;
To provide a video floppy disk recording and reproducing device in which either an odd field or an even field of a video signal is not continuously reproduced during two consecutive vertical synchronization periods.

Means for Solving the Problems In order to solve the above-mentioned problems, the video floppy disk recording and reproducing apparatus of the present invention determines whether the video signal recorded on each track of a magnetic recording medium is an odd field video signal or an even field video signal. storage means for storing the odd-even information determined by the above, and when moving tracks during playback, a field signal recorded on a magnetic recording medium and a 1/2 horizontal A control means for controlling head switching and switching with a signal delayed by a synchronization period, and means for preventing continuous reproduction of either the odd field or the even field of the video signal during two consecutive vertical synchronization periods. It is.

According to the above-described structure, the present invention combines a field signal recorded on a magnetic recording medium and a signal delayed by 1/2 horizontal synchronization period according to the odd-even field of the recorded video signal of the currently reproduced track and the moving track. In order to control switching and head switching, the odd and even fields of the video signal are alternately reproduced every vertical synchronization signal during movement, eliminating skew in the two parts of the screen.

Example Examples of the present invention will be described below.

FIG. 1 shows a block diagram of a first embodiment of the present invention. Components in FIG. 1 with the same numbers as in FIG. 2 are equivalent to the conventional technology, and their explanation will be omitted.

2o is an odd-even field discrimination circuit that discriminates whether the video signal processed by the reproduced video signal processing circuit 6 is an odd-field video signal or an even-field video signal, and 21 is a video floppy that uses the information discriminated by the odd-even field discrimination circuit 2o. A storage circuit 22 stores information for all 15 tracks, and a switching control circuit 22 controls switching of the switching switch 9 and the head switching switch 1o based on the odd-even field information before and after the movement.

When performing trunk movement to a field track, the system control circuit 19 reads the odd-even field information of the currently played track and the track to be moved from the storage circuit 21, and if the odd-even fields of the two read tracks are the same, the vertical synchronization signal is After synchronizing and moving within one vertical synchronizing signal period, the changeover switch 9 is switched in the opposite direction from before the movement by the switching control circuit 22 in synchronization with the vertical synchronizing signal,
When the odd-even fields are different, the changeover switch 9 is not changed.

When moving a track to a frame track, the system control circuit 19 reads the odd-even field information of the currently played track and the track to be moved from the storage circuit 21, and if the odd-even fields of the two read tracks are the same, the information is synchronized with the vertical synchronization signal. After moving one track every vertical synchronization period, the head changeover switch 10 is switched by the switching control circuit 22 to the direction opposite to the track in which the odd-even field information has been read. Switch to the track that has been loaded.

With the above structure, the odd and even fields of the video signal are alternately switched for each vertical synchronization signal when moving a track.When the video output terminal is connected to a TV monitor and played back, skew occurs on the screen. This has the excellent effect of making the screen transitions extremely smooth.

Effects of the Invention According to the present invention as described above, two vertical synchronizations in which either the odd field or the even field of the 7-yield video signal are continuous even if the video signal recorded on the video phronopi is moved back You can move the track without the period being the same and change the screen without any skew at the top of the screen! 7 can be obtained with the excellent effect of smoothing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a video floppy disk recording and reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional example. 20... Odd-even field discrimination circuit, 21...
. . . Memory circuit, 22 . . . Switching control circuit.

Claims (1)

[Claims] a recording means for recording a video signal on a magnetic recording medium having a plurality of substantially concentric tracks; a reproducing means for reproducing the video signal recorded on the magnetic recording medium; a recording/reproduction switching means for switching between recording and reproduction; a magnetic head that contacts two adjacent tracks of a magnetic recording medium; a moving means that moves the magnetic head in the radial direction of the magnetic recording medium; and a field signal recorded on the magnetic recording medium that is delayed by a 1/2 horizontal synchronization period. a switching means for switching between a delayed signal and an undelayed signal in the delay means, a head switching means for switching between two adjacent tracks recorded and reproduced by the magnetic head, and a video signal reproduced by the reproduction means. a discriminating means for discriminating between odd and even fields; a storage means for storing odd-even information discriminated by the discriminating means for all tracks of the magnetic recording medium; and when the magnetic head is moved;
It is characterized by comprising a control means for controlling the switching of the switching means and the head switching means so that the odd-even fields are different before and after the movement based on the odd-even information of the track before the movement and the odd-even information of the track after the movement. A video floppy disk recording and playback device.