JPH03183280A - Video signal recording and playback device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video signal having a simultaneous reproduction function in which the timing at which a recording signal is recorded and the timing at which a reproduction signal is reproduced are different from each other with respect to the rotational phase of a rotating cylinder. The present invention relates to a video signal recording and reproducing device that can provide the same monitor screen as the video signal that is actually edited when previewing editing.

Conventional technical recording and reproducing equipment W (hereinafter simply referred to as VTR) for video signals for business use or broadcasting uses a so-called "VTR" system that records video signals actually recorded on a recording medium while playing back and checking them. Simultaneous playback is essential. In order to realize this simultaneous reproduction, a playback head is arranged on a rotating cylinder at a predetermined angle with the recording head, the recording head records a video signal on a recording medium, and the playback head follows the recording head. A configuration is adopted in which the recorded video signal is reproduced by tracing it on the recording medium.

Problems to be Solved by the Invention However, in the above configuration, the timing at which a recording signal is recorded on the recording medium and the timing at which it is reproduced are different from each other between the recording head and the reproduction head with respect to the rotational phase of the rotating cylinder. The mounting differs by the time △T due to the angular difference, so the mode switches from the ■-■ mode in which the signal reproduced from the recording medium is processed as a reproduced signal to the E-E mode in which the recorded signal is processed as a reproduced signal without going through the recording medium. At this point, or at the time of switching from E-E mode to V-■ mode, temporal discontinuity (hereinafter simply referred to as skew) or signal loss occurs in the signal input to the reproduction signal processing circuit by the amount of ΔT. It turns out.

FIGS. 3(a) to 3(f) are operational waveform diagrams showing skew and signal loss in preview when editing using a conventional VTR. Preview is performed by playing back the tape (■-V mode) and checking the portion to be edited in advance by switching to E-E mode. The timing of the recording signal J and the reproduction signal differs by a time ΔT due to the difference in mounting angle between the recording head and the reproduction head, and the reproduction processing manual signal M is obtained by switching these according to the mode signal. It is. The reproduction processing output signal N is obtained by removing the skew from the reproduction processing input signal M, but ■-
The signal corresponding to ΔT is missing at the switching point between the ■ mode and the E-E mode.

The monitor screen at the mode switching timing in preview, that is, at the editing timing, is important in confirming whether editing is performed at the desired timing, and the occurrence of signal dropouts poses a major problem.

In view of the above, an object of the present invention is to provide a video signal recording and reproducing device in which a recording head and a reproducing head are separated, and which does not cause skew or signal dropout when switching operation modes. do.

Means for Solving the Problems In order to solve the above problems, the present invention provides a storage means for temporarily storing recorded signals, and a recording head that traces the timing at which the recorded signal is output from the storage means depending on the operation mode and then reproduces it. means for controlling the storage means so that the time difference until the head traces is different; means for recording and modulating the signal output from the storage means; and a reproduction modulation signal reproduced via the recording modulation signal and the reproduction head. and means for switching between the two.

Operation According to the above-mentioned Precept III, the present invention does not cause temporal discontinuity in the video signal input to the reproduction signal processing circuit even when switching between the E-E mode and the V■ mode, so a stable monitor screen can be obtained. In particular, it is possible to obtain an editing preview monitor screen that is exactly the same as the video signal being edited during editing.

Embodiment FIG. 1 is a block diagram of signal processing of a video signal recording and reproducing apparatus in an embodiment of the present invention. In Figure 1, 1
2 is an input terminal for inputting a recorded video signal, 2 is a sync separation circuit that separates a sync signal from the input video signal, and 3 is a horizontal sync signal separated by the sync separation circuit 2, and a clock signal and various other types from the vertical sync signal. A system control circuit that generates a timing signal and controls the operation of the system, 4 an A/D converter that digitally converts the input video signal using the clock signal, and 5 a video signal that records the digitally converted video signal. 6 is a storage circuit that temporarily stores the recorded video signal, and 7 generates an address for the storage circuit and stores it in accordance with the mode signal output from the system control circuit 3. a storage circuit control circuit that controls the output timing of the circuit; 8 a D/A converter that converts the recorded video signal output from the storage circuit into analog; 9 a °FM modulator;
10 is a head amplifier; 11 is a recording-only head mounted on a rotary cylinder for recording a recording FM signal; 12 is a magnetic tape; 13 is a reproduction-only head attached to the rotary cylinder for reproducing the recorded recording FM signal. , 14 is a head amplifier; 15 is a switch that switches and outputs the recording FM signal output from the FM modulator 9 and the reproduction FM signal according to a mode signal output from the system control circuit 3; 16 is an FM demodulator; 17 is F
A reproduction signal processing circuit performs the reverse processing of the M demodulated reproduction video signal to that during recording, and 18 is an output terminal from which the reproduction signal is output.

FIGS. 2(a) to 2(b) are operational waveform diagrams showing the operation of this embodiment. In FIGS. 2(a) to (h), A is the rotation reference signal of the rotary cylinder synchronized with the frame frequency of the human-powered video signal, B is the first recording signal output at the first timing, and C is the first recording signal. A second recording signal is output at a timing △T later than the recording signal, D is a first mode signal that controls the output timing of the recording signal, E is a recording FM signal modulated by the FM modulator 9, and F is a recording FM signal modulated by the FM modulator 9. The playback FM signal played from the tape, G is the second
The mode signal H is a reproduction processing manual signal.

The operation of the video signal recording and reproducing apparatus of this embodiment configured as described above will be described below.

The video signal manually input from the input terminal 1 is sent to the synchronization separation circuit 2,
and the A/D converter 4 manually. The synchronization separation circuit 2 separates a horizontal synchronization signal and a vertical synchronization signal. The system control circuit 3 generates a clock signal based on the synchronization signal separated by the synchronization separation circuit 2, and also generates horizontal, field, and frame timing pulses, and a mode signal. The video signal digitally converted by the A/D converter 4 is converted into a recorded video signal by the recording signal processing circuit 5, and then input to the storage device 6. This storage device 6 is controlled by a storage circuit control circuit 7, and outputs the first recording signal B in the recording mode to the D/A converter 9 at the timing of the second recording signal C in other modes. . This mode switching is performed within the vertical blanking period of the first recording signal B. The D/A converted recording signal is F
The signal is modulated by the M modulator 9 and recorded on the magnetic tape 12 via the head amplifier 10 and the recording head 11, and is input to the switch 15. Recorded recording FM signal E
The recording-only head 11 and the reproduction-only head 13
Attachment and simultaneous reproduction are delayed by a time difference ΔT caused by the angle. Playback-only head 13 and head amplifier 1
The reproduction signal reproduced through the switch 4 is input to the switch 15. This switch switches and outputs the recording FM signal E and the reproduction FM signal F according to the second mode signal G. This signal is FM demodulated and reproduced manually as a signal H
It is then processed by the reproduction signal processing circuit 17 and sent to the output terminal 18.
Output to.

As explained above, according to this embodiment, in a mode other than the recording mode, the recorded video signal delayed by ΔT from that in the recording mode is supplied to the reproduction signal processing section, so that the recording FM signal and the reproduction FM signal are It is possible to obtain a reproduced signal without skew or signal dropout because the timings between the two are consistent.

Although the present embodiment has been described using an example in which a video signal is recorded using FM modulation, the same effect can be achieved even in the case of digital recording.

As described in detail, according to the present invention, when the recording modulation signal is supplied to the reproduction signal processing section, it is supplied at the same timing as the reproduction modulation signal, so that simultaneous reproduction with different recording and reproduction timings is possible. Even if the VTR is equipped with
-No signal loss or skew occurs when switching between V mode and E-E mode, and you can accurately check the image at the editing timing when previewing the editing mode, which has a very practical effect. big.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a video signal recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is an operation waveform diagram of the embodiment, and FIG.
The figure is an operational waveform diagram of a conventional video signal recording and reproducing device. 6... Memory circuit, 7... Memory circuit control circuit, 11... Record-only head, 13...
...Playback-only head, 15...Switch.

Claims (1)

[Claims] A means for recording and reproducing video signals on a recording medium, which includes a recording head and a reproducing head on a rotating cylinder, a storage means for temporarily storing the recorded signal, and a timing at which the recording signal is output from the storage means according to an operation mode. means for controlling the storage means so that the time difference between when the recording head traces the recording medium and when the reproduction head traces the recording medium; means for recording and modulating the signal output from the storage means; and recording modulation. 1. A video signal recording and reproducing apparatus, comprising at least means for switching between a signal and a reproduced modulated signal reproduced from the reproducing head.