JP2722736B2 - Video signal recording and playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention 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 are reproduced differ with respect to the rotation phase of a rotary cylinder. The present invention relates to a video signal recording / reproducing apparatus which can obtain the same monitor screen as a video signal actually edited at the time of editing preview.

2. Description of the Related Art In a commercial or broadcast video signal recording / reproducing apparatus (hereinafter, simply referred to as a VTR), a video signal actually recorded on a recording medium is reproduced and confirmed while recording, so-called simultaneous reproduction. Is mandatory. In order to realize this simultaneous reproduction, a recording head is arranged at a predetermined angle with the recording head on the rotating cylinder, a video signal is recorded on a recording medium by the recording head, and the recording head follows the recording head. A configuration is adopted in which the recorded video signal is reproduced by tracing on a recording medium.

However, in the above-described configuration, the timing at which a recording signal is recorded on a recording medium and the timing at which the recording signal is reproduced with respect to the rotation phase of the rotating cylinder are determined by the mounting of the recording head and the reproducing head. At the time of switching from the VV mode in which the signal reproduced from the recording medium is processed to the reproduction signal to the EE mode in which the recording signal is processed without using the recording medium due to the difference of the time ΔT due to the angle difference, or At the time when the mode is switched from the EE mode to the VV mode, the signal input to the reproduction signal processing circuit is temporally discontinuous (hereinafter simply referred to as skew) by the above-mentioned ΔT or a lack of signal occurs. .

3 (a) to 3 (f) are operation waveform diagrams showing skew and missing signals in a preview when editing using a conventional VTR. The preview is for switching the part to be edited in advance to the EE mode while playing back the tape (VV mode) and checking it. The timing of the recording signal J and the timing of the reproduction signal K are different from each other by a time ΔT due to the mounting angle difference between the recording head and the reproduction head, and the reproduction processing input signal M is such that these are switched according to the mode signal L. is there. The reproduction processing output signal N is obtained by removing the skew from the reproduction processing input signal M.
At the switching point between the V mode and the EE mode, a signal corresponding to ΔT is missing. The mode switching timing in the preview, that is, the monitor screen at the editing timing is important for confirming whether or not the editing is performed at a desired timing, and the occurrence of a signal loss is a major problem.

In view of the foregoing, an object of the present invention is to provide a video signal recording / reproducing apparatus which does not cause skew or signal loss when switching an operation mode of a video signal recording / reproducing apparatus in which a recording head and a reproducing head are separated. I do.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a storage unit for temporarily storing a recording signal, and a recording head that traces the timing at which the storage unit is output from the storage unit depending on an operation mode, and reproduces the timing. Means for controlling the storage means so as to differ by a time difference until the head traces, means for recording and modulating a signal output from the storage means, a recording modulation signal and a reproduction modulation signal reproduced via the reproduction head And means for switching between the two.

Effect of the Invention According to the present invention, even if the mode is switched between the EE mode and the VV mode, a temporal discontinuity of the video signal input to the reproduction signal processing circuit does not occur, so that a stable monitor screen can be obtained. In particular, it is possible to obtain a monitor screen having the same edit preview as the video signal to be edited at the time of editing.

Embodiment FIG. 1 is a block diagram of signal processing of a video signal recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, 1 is an input terminal for inputting a recording video signal, 2 is a synchronization separation circuit for separating a synchronization signal from the input video signal, 3 is a horizontal synchronization signal and a vertical synchronization signal separated by the synchronization separation circuit 2 , A system control circuit for generating a clock signal and various timing signals, and controlling the operation of the system; 4, an A / D converter for digitally converting the input video signal using the clock signal; and 5, a digitally converted video signal. A recording signal processing circuit for converting a signal into a recording video signal; 6 a RAM or the like; a storage circuit for temporarily storing the recording video signal; 7 generating an address of the storage circuit;
A storage circuit control circuit for controlling the output timing of the storage circuit according to a mode signal output from the system control circuit 3; 8, a D / A converter for converting a recording video signal output from the storage circuit into an analog signal; Device, 10 is a head amplifier, 11 is a recording-only head attached to a rotating cylinder to record a recording FM signal, 12 is a magnetic tape, 13 is a reproducing-only attached to the rotating cylinder that reproduces the recorded FM signal recorded. Head, 14 is a head amplifier,
Reference numeral 15 denotes the recorded FM signal output from the FM modulator 9 and the reproduction
A switch for switching and outputting an FM signal in accordance with a mode signal output from the system control circuit 3;
A demodulator 17 is a reproduction signal processing circuit for performing the reverse processing of the reproduction video signal demodulated by FM when recording, and 18 is an output terminal for outputting the reproduction signal.

2 (a) to 2 (h) are operation waveform diagrams showing the operation of the present embodiment. 2 (a) to 2 (h), A is a rotation reference signal of the rotary cylinder synchronized with a frame frequency of an input video signal, and B is a first signal output at a first timing.
C, a second recording signal that is output at a timing later by ΔT than the first recording signal, D is a first mode signal that controls the output timing of the recording signal, and E is an FM modulator 9. The modulated recording FM signal, F is a reproduction FM signal reproduced from the tape, G is a second mode signal for controlling the switch 15, and H is a reproduction processing input signal.

The operation of the video signal recording / reproducing apparatus of the present embodiment configured as described above will be described below. Input terminal 1
Is input to the sync separation circuit 2 and the A / D converter 4. 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 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 recording video signal by a recording signal processing circuit 5 and input to a storage device 6. The storage device 6 is controlled by a storage circuit control circuit 7, and outputs the first recording signal B to the D / A converter 9 at the timing of the second recording signal C in the other modes in the recording mode. This mode switching is performed within the vertical blanking period of the first recording signal B. The D / A converted recording signal is modulated by the FM modulator 9, recorded on the magnetic tape 12 via the head amplifier 10 and the recording-only head 11, and input to the switch 15. The recorded recording FM signal E is transmitted to the recording head 11.
Simultaneous reproduction is delayed by a time difference ΔT caused by the mounting angle between the head and the read-only head 13. Read-only head 1
3, and a reproduction signal reproduced through the head amplifier 14 is input to the switch 15. This switch operates the recording FM signal E and the reproduction FM signal F in accordance with a second mode signal G.
And output. This signal is FM-demodulated and becomes a reproduction processing input signal H, which is processed by the reproduction signal processing circuit 17 and output to the output terminal 18.

As described above, according to the present embodiment, in other than the recording mode, the recording video signal delayed by ΔT from the recording mode is supplied to the reproduction signal processing unit. And the reproduced signal can be obtained without any skew or loss of signal.

In the present embodiment, the case where the video signal is FM-modulated and recorded is described as an example. However, the effect is the same even in the case of digital recording.

As described above, according to the present invention, when the recording modulation signal is supplied to the reproduction signal processing unit, the recording modulation signal is supplied at the same timing as the reproduction modulation signal. Even with a VTR equipped with functions,
There is no signal loss or skew when switching between the VV mode and the EE mode, and the image at the edit timing can be accurately confirmed at the time of preview in the edit mode. Big.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video signal recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is an operation waveform diagram of the embodiment, FIG.
FIG. 1 is an operation waveform diagram of a conventional video signal recording / reproducing apparatus. 6 ... memory circuit, 7 ... memory circuit control circuit, 11 ... recording only head, 13 ... reproduction only head, 15 ... switch.

Claims (1)

(57) [Claims] 1. A recording head comprising a recording head and a reproducing head on a rotary cylinder, means for recording and reproducing a video signal on a recording medium, storage means for temporarily storing the recording signal, and a recording signal from the storage means depending on an operation mode. Means for controlling the storage means so that the output timing differs by the time difference from when the recording head traces the recording medium to when the reproduction head traces, and the signal output from the storage means is recorded and modulated. And a means for switching between a recording modulation signal and a reproduction modulation signal reproduced from the reproduction head.