JPH0832065B2 - Video signal recording method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention inserts a time-axis compressed chrominance signal in a horizontal blanking period of a luminance signal, and the horizontal synchronization signal is positive polarity synchronization and has a short horizontal synchronization signal section. For example, multiple sub-Nyquist sample encoding signals (hereinafter MUSE
Signal) and the like are recorded in a recording device.

Structure of conventional example and its problems One of the high-definition video signal transmission methods is the MUSE method that compresses and transmits the band.

FIG. 1 shows an example of the MUSE system signal waveform. In FIG. 1, 1 is a waveform of a frame pulse line inserted for each frame of the MUSE signal, and 2 is a waveform of a video signal line.

A in the frame pulse line 1 is a frame pulse,
B is a horizontal synchronizing signal. B in video signal line 2
Is a horizontal synchronizing signal, C is a luminance signal, and D is a time-axis compressed color signal.

As described above, in the MUSE method, since the time-axis compressed color signal D is time-division multiplexed in the horizontal blanking interval, the interval of the horizontal synchronizing signal B is very short, about 0.6 μsec. The horizontal synchronizing signal B is a pulse that rises or falls within the black level and white level of the luminance signal.

Therefore, in order to separate the horizontal sync from the MUSE signal, it is necessary to detect the frame pulse A and open the gate at the horizontal sync signal position to separate the horizontal sync.
Horizontal sync separation cannot be done by level detection like NTSC signals.

Therefore, when the MUSE signal is recorded / reproduced on / from a recording device such as a VTR, if the reproduced MUSE signal has a large amplitude jitter, a time base fluctuation such as a skew, or the frame pulse dropout, the horizontal direction of the MUSE signal is generated. There is a problem that it is difficult to gate and detect the synchronization signal, and accurate horizontal synchronization separation cannot be performed.

Further, since the horizontal sync signal B of the MUSE signal is a pulse that rises or falls, the horizontal sync signal B is easily subject to different waveform deformations at the rising and falling pulses due to the emphasis, clip and RF characteristics during recording and reproduction, and the horizontal sync signal is accurate. There is a problem that it cannot be separated. This is a further problem in compatibility.

Further, there is a problem that the accuracy of horizontal sync separation deteriorates with the deterioration of the S / N of the reproduced signal.

The above problems associated with recording / playback of a MUSE signal on a recording device such as a VTR are major problems in the MUSE system as a high-definition video signal system.

An object of the present invention is to solve the above problems and to record and reproduce a video signal such as the MUSE signal in a recording device such as a VTR,
Even if there is a temporal fluctuation such as large amplitude jitter or skew, dropout, or S / N deterioration of the reproduced signal, the phase can be detected accurately and a stable reproduced clock signal can be obtained. An object of the present invention is to provide a video signal recording method for reproducing a signal with high image quality.

According to the video signal recording method of the present invention, when a video signal such as a MUSE signal is recorded in a recording device, a section including a signal in at least all effective scanning sections of an input video signal is extracted and time-axis compressed. , A negative sync signal and a burst signal within the recording band are newly inserted in a newly obtained section within one horizontal scanning period of the input signal to record jitter during reproduction.
Even if there is a time-based fluctuation such as skew, dropout, or S / N deterioration of the playback signal, horizontal sync separation can be performed directly by level detection during playback, and S / N from the rising edge of negative sync or the burst signal. Since it is possible to detect the phase with good N, it is possible to obtain a stable reproduction clock signal and obtain a high-quality reproduction signal.

DESCRIPTION OF THE EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, a MUSE signal will be described as an example of an input video signal. FIG. 2 is a waveform diagram of the video signal recording method in the first embodiment of the present invention. In FIG. 2, 3 is the MUSE signal waveform of the video signal line, and 4 is the time axis compressed video signal waveform.

At the time of recording, the effective video signal section E of the MUSE signal 3 is time-axis compressed to such an extent that the recording band is not increased so much and stored in the section F of the time-axis compressed video signal 4. A horizontal sync signal is newly inserted in the horizontal sync signal section G within the horizontal blanking period which has been extended in time.

FIG. 3 shows an example of the horizontal sync signal newly inserted. In FIG. 3, reference numeral 5 is a waveform diagram when the negative sync signal and the burst signal J within the recording band are inserted.

First, the negative sync signal will be described. The rising and falling parts of the negative sync signal have a certain slope so that the recording band has many spectra so that the waveform is less deformed.

During reproduction, the leading edge of the negative sync signal is synchronously separated by level detection, the gate pulse of the trailing edge of the negative sync signal is obtained from the separated sync signal, and the trailing edge of the negative sync signal is gated to form a phase detection signal. . The trailing edge of the negative sync signal is VTR
When recording / reproducing on a recording device such as
Since there are few moiré components due to zero shift in modulation / demodulation and unnecessary components such as carrier leak, and waveform deformation due to emphasis and clipping is less likely to occur, accurate horizontal synchronization detection can be performed, and the gate can be used to detect the trailing edge of the negative polarity synchronization signal. Since it is taken out, the variation in phase detection with other devices is extremely small.

Next, the burst signal will be described. The burst signal is inserted into the black level of the luminance signal and at the time of reproduction, the insertion position of the burst signal is detected from the reproduced video signal by level detection to obtain a burst gate pulse, and the reproduced video signal is delayed to obtain the burst gate pulse. To extract the burst signal. After filtering this burst signal with BPF, phase detection is performed.

Since this phase detection is performed using the filtered burst signal, it is possible to detect a phase with a good S / N even if the S / N of the reproduced signal is bad. Further, since the burst signal is inserted in the black level of the luminance signal, the horizontal synchronization can be directly separated by the level detection, so that the burst gate can be stably performed even if the reproduced video signal has a large time variation component.

Next, a case where the negative sync signal and the burst signal J are inserted will be described. At the time of reproduction, the negative sync signal is horizontally sync-separated by level detection, a burst gate pulse is obtained from the separated horizontal sync signal, the burst signal is gated, taken out and filtered by the BPF, and then phase detection is performed.

Even in this case, even if the S / N of the input signal is bad, phase detection with good S / N can be performed, and the negative sync signal can be directly separated by level detection, so a stable playback clock signal from a playback video signal with a large time-varying component Can be obtained.

 The second embodiment of the present invention will be described below.

FIG. 4 is a waveform diagram of a video signal recording method showing a second embodiment of the present invention. In FIG. 4, 6 is the MUSE signal waveform of the video signal line, and 7 is the time axis compressed video signal.

During recording, one horizontal scanning period M of the MUSE signal 6 is time-axis compressed and stored in the N section of the time-axis compressed video signal 7 to obtain a newly increased blanking period O. In the blanking period O, the horizontal synchronizing signal as shown in FIG. 3 of the first embodiment is inserted.

As described above, according to the present embodiment, all the video signals including the horizontal sync signal of the input video signal are time-axis-compressed and a new horizontal sync signal for recording to the recording device is inserted for recording and reproduction. At the time of reproduction, a reproduced video signal can be obtained by simply expanding the time axis without the operation of inserting the horizontal synchronizing signal, and the compression rate is increased by several percent as compared with the first embodiment. Thus, the same effect as that of the first embodiment can be obtained. In this case, the deterioration of the S / N of the reproduced video signal due to the increase of the recording band is about 0.3 dB as compared with the first embodiment, which is not a problem.

According to the video signal recording method of the present invention, a luminance signal and a chrominance signal are time-division-multiplexed, and a section including a signal within at least all effective scanning sections of an input video signal to which positive polarity synchronization is added is taken out, It is possible to directly separate the horizontal sync signal suitable for a recording device such as a VTR into the newly obtained section by level detection, that is, to detect the phase with an S / N better than the S / N of the reproduced video signal. By inserting and recording a horizontal sync signal, it is possible to reliably perform sync separation even if there is time variation such as jitter or skew in the playback video signal or S / N deterioration during playback, and the S / N is good and highly accurate. Since the phase can be detected, a reproduction clock signal that is accurately phase-synchronized with the input video signal can be obtained, and its practical effect is great in recording and reproducing a high-quality video signal. Further, when a new horizontal synchronization signal is newly inserted, a part of the effective section of the input video signal is not deleted, so that the entire effective scanning section is recorded and a part of the playback screen is not lost. The recording method of can be realized.

[Brief description of drawings]

FIG. 1 is a signal waveform diagram of the MUSE system, and FIG. 2 is the first of the present invention.
FIG. 3 is an operation waveform diagram in the embodiment of FIG. 3, FIG. 3 is a newly inserted synchronizing signal waveform diagram, and FIG. 4 is an operation waveform diagram in the second embodiment of the present invention. 1 …… MUSE signal frame pulse line, 2,3,6 …… MUSE
Signal Video signal line, 4, 7 ... Time axis compressed video signal, 5
...... New sync signal to be inserted.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-56-64585 (JP, A) JP-A-53-5926 (JP, A) JP-A-50-50815 (JP, A) JP-A-53- 109423 (JP, A)

Claims (3)

[Claims] 1. When an input video signal in which a luminance signal of a period C, a color signal of a period D and a positive sync signal of a period B are time-division multiplexed in one horizontal scanning period M is recorded in a recording device, the input is performed. The period X including at least the entire effective scanning period in which the luminance signal and the color signal of the video signal are time-division-multiplexed is taken out and time-axis compressed to be the time-axis compression effective signal of the period F (F <X). An image characterized in that a negative polarity synchronizing signal and a burst signal of several cycles are inserted into a period G (where G + F = M) longer than the period B of the synchronizing signal, and the time axis compression effective signal and time division multiplex recording are performed. Signal recording method. 2. A period E other than the positive sync signal of the input video signal.
The video signal recording method according to claim 1, wherein the input video signal of (E = X and E + B = M) is time-division-compressed to be a time axis compression effective signal of the period F. 3. A video signal in one horizontal scanning period M including a positive sync signal of an input video signal is time-division-compressed to be a time axis compression effective signal in a period F. The video signal recording method described in the item.