JPS6256083A - Recording and reproducing device for video signal - Google Patents

Abstract

PURPOSE:To obtain a horizontal synchronizing signal of high accuracy and to detect a phase detecting of high accuracy and to obtain a stable reproducing clock by inserting a burst signal in a horizontal blanking period and inserting a negative polarity pulse signal within a vertical blanking period. CONSTITUTION:A signal MUSE inputted from an input terminal 3 inserts a burst signal in place of the horizontal synchronizing signal within the horizontal blanking perod at a burst signal inserter 4. At the next, the negative polarity pulse signal is inserted in the vertical blanking period at a pulse signal inserter 5 and it is supplied to a modulator 8, receiving a frequency conversion, and is supplied to a recording amplifier 7, being amplified, and is recorded on a magnetic tape 9 by a video head 8. In a reproducing time, a signal recorded on the magnetic tape 9 is reproduced by the video head 8 and is amplified at a reproducing amplifier 10, being demodulated by a demodulator 11, and is processed at a time base corrector 3 which eliminates a time base fluctuation. Thereby, a reproduced synchronizing signal can be obtained accurately and the burst signal inserted to each line can be detected without fail, performing the phase detection of high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video signal for recording and reproducing a video signal whose horizontal synchronization signal is positive synchronization, such as a multiple fist sub-Nyquist sampling encoding signal (hereinafter referred to as MUSE signal). The present invention relates to a signal recording/reproducing device.

BACKGROUND ART There is a MUSE method as a method for transmitting a high-quality video signal with 1125 horizontal scanning lines (for example, Technical Report of the Television Society of Japan, Vo, 5.7, fG, 44). FIG. 5 shows an example of a signal waveform transmitted by this MUSE method. In FIG. 5, 1 is a waveform diagram of a frame pulse line inserted for each frame of the MUSE signal;
2 is a waveform diagram of the video signal line. A in frame pulse line 1 is a horizontal synchronizing signal, B is a frame pulse, C in video signal line 2 is a time-axis compressed color signal,
D is a luminance signal. In the MCUE signal shown in FIG. 5, since the time-base compressed color signal C is time-division multiplexed during the horizontal blanking period, the period of the horizontal synchronization signal A is very short, Q, about 6 μsec. Further, the horizontal synchronization signal A
is a rising or falling pulse within the black level and white level of the luminance signal.

Therefore, in order to separate the horizontal synchronization signal A from the MUSE signal, the frame pulse B is detected, a gate pulse is formed to separate the synchronization signal from the detected frame pulse, and the gate pulse is gated during the horizontal synchronization signal period. need to be opened.

Problems to be Solved by the Invention However, in the synchronization separation in which the frame pulse is detected and the gate is opened during the horizontal synchronization signal period, the MUSE
When a signal is recorded and reproduced on a recording/reproducing device such as a VTR, there is a problem that accurate horizontal synchronization separation cannot be performed if the reproduced signal has time axis fluctuations such as jitter or skew, or dropout of frame pulses.

Furthermore, since the horizontal synchronization signal A of the MUSE signal is a rising or falling pulse, it is susceptible to waveform deformation that differs between the rising and falling pulses due to emphasis/de-emphasis, clipping, etc. during recording and playback. Synchronization signal cannot be obtained.

When recording and reproducing a MUSE signal on a recording/reproducing device such as a VTR, if the above-mentioned problems exist, a high-quality reproduced video signal cannot be obtained.

The present invention solves the above-mentioned problems, and when recording and reproducing video signals such as MUSE signals on a recording and reproducing device such as a VTR, time axis fluctuations such as jitter and skew, dropouts, and S/H of the reproduced signal. Recording of video signals that can obtain a highly accurate horizontal synchronization signal even if deterioration occurs, as well as a stable reproduction clock through accurate phase detection and a high-quality reproduced video signal. The purpose is to provide a playback device.

Means for Solving the Problems The present invention provides a recording system with means for inserting a burst signal into the horizontal blanking period and a means for inserting a negative pulse signal into the vertical blanking period, and a reproducing system with the negative pulse signal. means for detecting a pulse signal; means for detecting a burst signal from the detected negative pulse signal; means for generating a reproduced horizontal synchronizing signal from the detected burst signal; This is a video signal recording and reproducing device provided with means for detecting a burst signal inserted into a video signal.

According to the above-described configuration, the present invention has a burst signal inserted into the horizontal blanking period in the video signal to be recorded, and a negative pulse signal is inserted in addition to the burst signal into the vertical blanking period. There is. During playback, the negative pulse signal has time axis fluctuations, dropouts, and S of the playback signal.
Even if there is a deterioration of /N, it can be detected reliably, and the burst signal during the period in which the negative pulse signal is inserted is
It is reliably detected by the first gate pulse obtained from the detected negative pulse signal. A highly accurate reproduced horizontal synchronization signal can be easily obtained from this detected burst signal. A second gate pulse is obtained to detect the burst signal in which the negative pulse signal is inserted, and the burst signal can be reliably detected by this second gate pulse, and as in the period in which the negative pulse signal is inserted, Accurately reproduced horizontal synchronization signals can be easily obtained. Due to the above-described operation, a reproduced horizontal synchronizing signal can be obtained with high precision, and the burst signal inserted in each line can be detected reliably, allowing highly accurate phase detection.

Embodiment FIG. 1 is a block diagram of a video signal recording and reproducing apparatus according to an embodiment of the present invention. In this embodiment, the recording and reproducing apparatus is a rotating two-head type VTR, and the input video signal is a MUSE signal.

The MUSE signal input from the input terminal 3 is supplied to a burst signal inserter 4, which inserts a burst signal in place of the horizontal synchronization signal within the horizontal blanking period. FIG. 2 is a waveform diagram of the MUSE signal with a new burst signal inserted, and 27 is the MUSE signal input to the burst signal inserter 4.
The signal 28 is a burst signal E instead of the horizontal synchronization signal A.
This is the MUSE signal with . The MUSE signal into which the burst signal has been inserted is supplied to the pulse signal inserter 5, and a negative pulse signal is inserted line by line during the vertical blanking period. FIG. 3 is a waveform diagram of the MUSE signal in the vertical blanking period in which a negative pulse signal is inserted, 29 is the MUSE signal in the vertical blanking period, and 3o is the MUSE signal in the vertical blanking period in which a burst signal and a negative pulse signal are inserted.
This is an SE signal. F is a negative pulse signal and is inserted at the end of the line by the pulse signal inserter 5. The rising portion of this negative pulse signal has an appropriate slope so that it is less susceptible to waveform deformation during recording and reproduction. The burst signal E is inserted by the burst signal inserter 4. The MUSE signal, in which a burst signal and a negative pulse signal are inserted during the vertical blanking period, and only the burst signal is inserted outside the vertical blanking period, is supplied to the modulator 6, subjected to frequency modulation, and then supplied to the recording amplifier 7. After being amplified by a recording amplifier 7, the video head 8 records the signal onto a magnetic tape 9.

During reproduction, the signal recorded on the magnetic tape 9 is reproduced by the video head 8, amplified by the reproduction amplifier 10, and demodulated by the demodulator 11. 31 surrounded by a broken line constitutes a time base corrector (hereinafter referred to as TBC) that removes time base fluctuations. FIG. 4 is a waveform diagram of each main part of the TBC.

The recorded video signal is as shown in FIG. 4a, but the demodulated video signal includes time axis fluctuations such as jitter and skew that occurs when switching heads. FIG. 4 is a waveform diagram of a video signal with skew, and G is the line with skew. The video signal shown in FIG. 4 is supplied to the pulse separation circuit 12, which separates the negative pulse signal inserted into the vertical blanking period. This pulse separation circuit can separate negative pulse signals by level detection, so even if skew occurs, separation can be ensured. FIG. 4C shows the separated negative pulse signal, and the negative pulse signal is sent to the gate pulse generator 1.
3 is supplied to 1. Forms a first gate pulse for detecting a burst signal inserted from the second line counting from the beginning of the vertical blanking period to the first line of the video signal period after the end of the vertical blanking period. do.

FIG. 4d is the first gate pulse. The first gate pulse is supplied to the burst detector 14 via the switch 15 to detect the burst signal from the second line of the vertical blanking period to the first line of the video signal period. The burst signal detected by the burst detector 14 is transmitted to a regenerative horizontal synchronization signal generator (hereinafter referred to as a regenerative fH generator) 16.
is supplied to generate regeneration fH. The reproduced fH is supplied to the gate pulse generator 17, and the reproduced fH detected from the nth line of the video signal period forms a second gate pulse for detecting the burst signal on the (n+1)th line. . FIG. 4q is the second gate pulse. By supplying a second gate pulse to the burst detector 14 via the switch 16, the second gate pulse of the video signal period is
A burst signal inserted from the th line to the first line of the vertical flanking period is detected. The control signal for the switch 15 is the signal shown in the fourth diagram, and during the period when the control signal is "high", the first gate pulse is "0 low".
The switch 15 is controlled so that the second gate pulse is supplied to the burst detector 14 during the period . By the above-described operation, even if skew occurs due to head switching, burst signals during all horizontal blanking periods of the reproduced video signal are reliably and accurately detected, and reproduction fH can be easily obtained using these burst signals. In FIG. 4, e is the detected burst signal, and f is the reproduced burst signal.

The burst signal and reproduction/H are generated by a reproduction clock generator 19.
The phase of the burst signal is detected and a reproduced clock synchronized with the phase of the burst signal, that is, the phase of the reproduced video signal with time axis fluctuation is generated.With this reproduced clock, the reproduced video signal is output to the A/D. Analog-to-digital conversion is performed at 1B, and the data is written into the memory 21 using the reproduced clock. A write address signal is obtained by the write address generator 2o using the reproduction f and the reproduction clock, and is supplied to the memory 21.

The read clock is obtained from the reference horizontal synchronization signal (hereinafter referred to as reference fH) from the terminal 26, and the read address signal is obtained from the reference f and the reference clock from the reference clock generator 23, both of which are supplied to the memory 21. , memory 2
1 and performs digital-to-analog conversion using the D/A 22, a reproduced MUSE signal whose time axis has been corrected is outputted from the terminal 25.

If the detected burst signal is filtered at the front stage of the reproduced clock generator of this embodiment, the phase of the burst signal can be detected in a state of good S/H even for a video signal with degraded S/H.

Further, in the case of this embodiment, since only the burst signal is newly inserted into the horizontal synchronization signal period of the video signal period, there is no need to time-base compress the video signal and create a new period for inserting the burst signal. In addition, if the rising and falling horizontal synchronization signals are left as they are and the recording/reproduction is started, the burst signal may be inserted by compressing the time axis for the period of the burst signal during recording. Needless to say.

In this embodiment, the period in which the negative pulse signal is inserted is the entire vertical blanking period, but the period in which the negative pulse signal is inserted is the blanking period from the line immediately after head switching to the line immediately before the video signal period. It may be a period. [The present invention is still applicable to the case where the video signal is divided into two channels in order to reduce the band of the video signal to be recorded, and the time axis of one line of the video signal is expanded by about twice before recording and playback.] It is clear that it can be done.

Furthermore, when recording and reproducing broadband video signals on a rotating two-head VTR, the number of rotations of the VTR's cylinders may be increased in order to lengthen the recording wavelength.

For example, the rotation speed is 3600 rpm, which is twice the normal speed.
When 1 field of video signal is recorded on the magnetic tape, 2
The track is divided into tracks and recorded, and the reproduced image shows skew due to head switching in the center of the screen. In order to correct this skew, the present invention provides a new granking period for the video signal (7>time axis by 77 points) before and after head switching during recording, and also applies to a recording/reproducing device that corrects the time axis during playback. Needless to say, it can be applied.

As described in detail, according to the present invention, when a video signal is recorded and played back by a recording/playback device, time axis fluctuations such as jitter and skew, dropouts, and S/H deterioration of the playback signal occur. It is also possible to obtain a highly accurate horizontal synchronization signal, to perform highly accurate phase detection, and to obtain a reproduced clock that is completely phase-synchronized with the reproduced video signal, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a video signal recording and reproducing apparatus according to an embodiment of the present invention, and FIG. Third. FIG. 4 is an operational waveform diagram of the same embodiment, and FIG. 6 is a waveform diagram of the MUSE signal. 4...Burst signal inserter, 5...Pulse signal inserter, 12...Pulse minute RIil
13.17...Gate pulse generator, 14
... Burst detector, 16 ... Regenerative horizontal synchronization signal generator 〇 Name of agent Patent attorney Satoshi Nakao
Male and 1 other person ℃ Figure 2 I Figure 3 F

Claims (2)

[Claims] (1) A video signal recording and reproducing device for recording and reproducing a video signal whose horizontal synchronization signal is positive synchronization, which includes means for inserting a burst signal into the recording system during the horizontal blanking period, and a negative pulse signal during the vertical blanking period. and means for detecting the negative pulse signal in the reproduction system, means for detecting a burst signal from the detected negative pulse signal, and generating a reproduction horizontal synchronization signal from the detected burst signal. What is claimed is: 1. A video signal recording and reproducing apparatus comprising: means for detecting a burst signal inserted into the next line from the reproduced horizontal synchronizing signal. (2) Claim (1) characterized in that the recording/reproducing device has a rotating head, and the line into which the negative pulse signal is inserted is at least the line immediately after head switching during the blanking period. A recording and reproducing device for the video signal described above.