JPS63224061A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the generation of a skew at the time of recording two picture frames by controlling the travel of a magnetic tape at a constant reproducing speed, and impressing a phase difference between a horizontal sync signal, separated from a regenerated first video signal, and the horizontal sync signal, separated from a second video signal, to a drum servo. CONSTITUTION:At the time of recording two picture frames, the tape is made to reproducing-travel at the constant speed by the control signal for reproduction. The horizontal sync signal, extracted from a first video signal S1, which is recorded already, is made to pass through an AFC circuit 4, and is divided into a prescribed frequency dividing ratio, and is inputted to a phase comparison circuit 6. At such a time, the horizontal sync signal, extracted from a second video signal S2, to be recorded newly, is divided into the prescribed frequency dividing ratio, and inputted to the phase comparison circuit 6. A phase difference signal S3, outputted from the phase comparison circuit 6, comes to be the signal S7 to control a phase according to the second video signal S2, and is added together with a speed difference signal S6, and comes to be the control signal S9 to control the drum servo, and a drum motor 11 is servo-controlled on the basis of the said control signal S9.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a magnetic recording/reproducing device, and relates to a camera-integrated video tape recorder (VT) capable of recording two screens.
R).

(Prior art) Conventionally, as one of the special recording methods of a camera-integrated VTR,
It is possible to record another video signal in a part of the video signal in which the video signal has already been recorded, and to display different videos on the upper and lower halves of the screen during playback, for example.

(Problems to be Solved by the Invention) However, in this type of special recording, the horizontal synchronization period between the already recorded video signal and the video signal to be recorded later is shifted, resulting in skinny.

Figures 2 (a) to (0) and Figure 3 are timing diagrams showing the occurrence of this skinny. indicates the timing to do so.

3A shows a PG signal, and in the same figure (C1 shows a video signal, code 1 shows a vertical synchronizing signal, and b shows a horizontal synchronizing signal part, respectively.

FIG. 3 is an enlarged view of the video signal portion corresponding to the rising edge of the switching signal, and the horizontal synchronization period is the normal period (I
There exists a period C that is shorter than H). Therefore, skinny distortion occurs on the screen.

(Means for Solving the Problems) A magnetic recording/reproducing apparatus of the present invention records a second video signal on a part of a first video signal already recorded on a magnetic tape, and The drive is controlled at a constant playback speed, and the phase error between the horizontal synchronization signal separated from the reproduced first video signal and the horizontal synchronization signal separated from the second video signal is added to the drum servo control. .

(Function) Once the first video signal recorded on the magnetic tape is in a reproduction state, the horizontal synchronizing signal is separated. On the other hand, the horizontal synchronization signal is also separated from the second video signal to be newly recorded.
The phase error between these two horizontal synchronization signals is added to the phase difference signal of the servo system that is controlled by the drum servo with the second video signal, and is Prevents horizontal synchronization phase disturbance.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus according to the present invention.

A first video signal S has already been recorded on the magnetic tape (not shown), and this video signal SI is outputted via the reproducing circuit 2 by switching the recording/reproducing switch 1 . The reproduced video signal output from the reproduction circuit 2 is input to the synchronization separation circuit 3, where the horizontal synchronization signal is extracted. This horizontal synchronization signal is stabilized through the AFC circuit 4 and input to the frequency divider circuit 5, and after being divided to a predetermined frequency division ratio, the phase comparator circuit 6
is input to. The AFC circuit 4 has the same configuration as that for removing disturbances due to dropouts, etc.
4a, a frequency divider circuit 4b, and a feedback loop of a phase comparator circuit 4C.

On the other hand, the second video signal St to be newly recorded is recorded on the magnetic tape via the recording circuit 7 and the previous recording re-switching switch 1 which switches to the recording side at a predetermined timing. Also,
The second video signal S2 is input to the synchronization separation circuit 8, where the horizontal synchronization signal is extracted, and then the frequency division circuit 4b,
The 0 phase comparator circuit 6 inputs the first video signal Sl and the second video signal S, The phase difference of the horizontal synchronizing signal extracted from the horizontal synchronizing signal and divided by the same frequency division ratio is determined, and a phase error signal S is output. In addition,
The timing at which the previous recording re-switching switch 1 is switched from the reproduction side to the recording side is controlled by a switching signal S10 using a delay pulse having a fixed delay time from a PG signal S4, which will be described later.

Incidentally, the drum motor 11 is subjected to drum servo control consisting of a phase servo system and a speed servo system. The phase servo system consists of a phase control loop circuit 13 which receives as input the PC signal S4 detected by the PC head 12, and the drum servo system comprises a speed control loop circuit which receives as input the FG signal S detected by the FG head 14. 15 are configured. Then, the phase error signal S output from the phase control loop circuit 13 and the phase error signal S3 are added 16.

The signal S after this addition is the speed control loop circuit 15
The control signal S for controlling the drum servo is obtained by adding 17 the speed error signal S outputted from the drum servo. This control signal S drives and controls the motor driver 18 and servo-controls the drum motor 11.

However, during so-called special recording that records two screens,
The tape is run at a constant speed using a playback control signal, and the phase of the rotary head 19 is controlled using a second video signal S8. This rotary head 19 traces the trunk of the already recorded first video signal Sl by controlling the phase of tape running. Then, the horizontal synchronizing signal extracted from the already recorded first video signal Sl is passed through the AFC circuit 4, frequency-divided to a predetermined frequency division ratio, and input to the phase comparison circuit 6. At this time, the horizontal synchronizing signal extracted from the second video signal S2 to be newly recorded is also frequency-divided to a predetermined frequency division ratio and input to the phase comparator circuit 6.

Then, the phase error signal S outputted from the phase comparison circuit 61J becomes a signal S for controlling the phase based on the second video signal S2, and is added to the speed error signal S to perform drum servo control. Control signal S.

becomes. As described above, since the drum motor 11 is servo-controlled based on the control signal S, it is possible to switch from the part where the first video signal S is recorded to the part where the second video signal St is newly recorded. Disturbance of the arrangement pattern of the horizontal synchronization phase when changing is prevented.

(Effects of the Invention) As described above, according to the present invention, it is possible to prevent skinny from occurring due to a shift in the horizontal synchronization period that occurs when recording two screens.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the magnetic recording/reproducing apparatus according to the present invention, FIG. 2 (a) to ((+) are timing diagrams showing the occurrence of skinny, and FIG. 3 is a video signal switching section. 3.8... Synchronization separation circuit 4... AFC circuit 6
... Phase comparison circuit 18 ... Motor driver 82
Figure t5 Kurano PG (jC No. 3 Figure IHIHIH

Claims (1)

[Claims] 1) A second video signal is recorded on a part of the first video signal already recorded on a magnetic tape, the magnetic tape is controlled to run at a constant playback speed, and the playback A magnetic recording and reproducing apparatus characterized in that a phase error between a horizontal synchronizing signal separated from a first video signal and a horizontal synchronizing signal separated from a second video signal is added to drum servo control.