JPS6052187A - Recording and reproducing system of video signal - Google Patents

Abstract

PURPOSE:To simplify the circuit for simultaneousity at reproduction by adding a discriminating pulse identifying a color difference signal to one of the color difference signal at each horizontal scanning period at recording of the video signal by the line sequential system. CONSTITUTION:The color difference signal B-Y where the color difference signal R-Y and the discriminating pulse 6 are added at each 1H period is fed to a line sequential switch 9. The color difference signal 10 subject to line sequential by the switch 9 is fed to a mixer 13 via an FM modulator 11. On the other hand, since the luminance signal Y is fed to the mixer 13 via an FM modulator 12, a multiplexed carrier video signal 14 is outputted from the mixer 13. The signal 14 is fed to a recording head 16 via a recording amplifier 15. The circuit for simultaneousity is simplified by extracting and utilizing the discrimination pulse at reproduction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video signal recording and reproducing method, and is particularly useful for recording and reproducing video signals using a line sequential method.

In France and other countries, a telephony system called the 5ECAIV1 system has been standardized. In this SECAM system, two color difference signals B-Y and R-Y are alternately switched for each scanning line, each frequency modulated using two different subcarriers, and superimposed on a luminance signal to form a carrier video signal. . Therefore, in the demodulation system of the carrier video signal, by extracting in parallel a signal delayed by one horizontal scanning period and a signal delayed by one horizontal scanning period, the color difference signal R thinned out every horizontal scanning period is
-Y, B -Y is the color difference signal R- one horizontal scanning period ago
Two consecutive color difference signals R- are supplemented by Y and B-Y.
I have obtained Y and B-Y.

For this reason, the demodulation system is provided with a switch for alternately extracting a signal delayed by one horizontal scanning period and a signal not delayed. Taking out two types of color difference signals in parallel in this way is called synchronization, and a switch for this purpose is called a synchronization switch.

The synchronization switch in the SECAM system is configured as follows: When obtaining a line sequential signal from the two color difference signals R-Y and B-Y, the frequency of the carrier wave is changed for each horizontal scanning period, and in the demodulation system, the frequency of the carrier wave is different. Based on the difference, the color difference signal RY,
It is switched by a signal indicating either B or Y. When attempting to magnetically record and reproduce a video signal such as a television signal using such a color difference signal discrimination method, a predetermined frequency band line that can be used for a carrier signal modulated by the color difference signals R-Y and B-Y is used. Since the frequency deviation between the carrier waves is also limited, there is a drawback that the circuit configuration for switching the synchronization switch becomes complicated.

In view of the above-mentioned drawbacks of the prior art, the present invention provides reliable two-way processing using a circuit with a simple configuration when reproducing video signals using the line-sequential method.
It is an object of the present invention to provide a video signal recording/reproducing method that allows different types of color difference signals to be synchronized. The present invention achieves this object by adding a discrimination pulse to identify one of two types of color difference signals every horizontal scanning period when recording a video signal, and extracting the discrimination pulse when reproducing the video signal. The technical idea is based on the fact that the synchronization switch is switched every horizontal period based on this discrimination pulse or with the detection of this discrimination pulse as a condition.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1(a) is a block diagram showing an apparatus for realizing a recording method according to an embodiment of the present invention. As shown in the figure,
The input terminal 1 receives the luminance signal Y of the video signal, the input terminal 2 receives the color difference signal RY of one of the video signals, the input terminal 3 receives the color difference signal B-Y of the other video signal, and the input terminal 4 receives the color difference signal Y of the video signal. A discrimination pulse 6 is supplied to the input terminal 5, and a line pulse 7 is supplied to the input terminal 5, respectively. Among these, the discrimination pulse 6 is a pulse that rises for a short time every horizontal scanning period (hereinafter abbreviated as IH). The line pulse 7 is a pulse that is formed by, for example, a horizontal drive signal that rises at the start and end of an IH, and repeats a rising p and a falling p for each IH. The waveform of this line pulse 7 is shown in FIG. 2(e). The adder 8 is a circuit that adds the discrimination pulse 6 to the color difference signal B-Y. Therefore, while the color difference signal R-Y is a signal consisting only of the color difference signal R-Y, as shown in FIG. 2(a), the color difference signal B-Y, which is the output signal of the adder 8, is , for example, in Figure 2 (b
, l, the discrimination pulse 6 is added to the color difference signal B-Y. The line sequential switch 9 is switched every 91H by the line pulse 7 to output color difference signals R-Y, B.
-Y.

is selectively output for each IH and line-sequentialized.

The waveform of this line-sequential color difference signal 10 is shown in FIG. 2(d). As shown in the figure, the color difference signal 10 is the color difference signal R-
It is a continuous signal in which Y and B-yl are repeated alternately. This color difference signal 10 is FM modulated by an FM modulator 11 to become a carrier color difference signal), and is multiplexed by a mixer 13 with a carrier luminance signal obtained by FM modulating the luminance signal Y by an FM modulator 12. Ru. The carrier video signal 14 thus formed is recorded by a recording head 16 via a recording amplifier 15 on a magnetic recording medium, for example, a magnetic disk (not shown).

FIG. 1 Φ) is a block diagram showing an apparatus for realizing a reproduction method according to an embodiment of the present invention. As shown in the figure, the reproducing head 17 is for reproducing the conveyed video signal 14 recorded on the magnetic recording medium by the recording device shown in FIG. 1(a). The carrier video signal 14 thus reproduced is passed through a head amplifier 18 to a bypass filter 19.
In the bypass filter 19, the carrier video signal 14 and the carrier luminance signal are lost and supplied to the FM demodulator 21.As a result, the luminance signal Y is output as the output signal of the FM demodulator 21. On the other hand, the low-pass filter 20 extracts the carrier color difference signal from the carrier video signal 14 and supplies it to the 'rFM7.J modulator 22.

As a result, a line-sequential color difference signal 10 is obtained as an output signal of the F-MIN adjuster 22. This color difference signal 10 is demodulated before IH and is supplied to the synchronization switch 24 at the same time as the other color difference signal 10 which is delayed by a delay circuit 23 for the same period.

That is, the color difference signal 10 as shown in FIG. 2(d) and the second
The IH-delayed color difference signal 10 shown in FIG. 3(e) is simultaneously supplied to the synchronization switch 24. The simultaneous switch 24 is connected to the delay circuit 23. Contact 24
c and a contact 24d directly connected to the FM4ν adjuster 22.
A switch 24a for selectively switching between and 24a and a switch 24 for selectively switching between similar contacts 24e and 24f.
It has b'ft. Among these, the contacts 24c and 24f and the contacts 24d and 24e are selected at the same time. Therefore, when the switch 24a selects the color difference signal RY, the switch 24b selects the color difference signal B-Y. That is, the signal demodulated at this moment is the color difference signal B - Y
.

, this color difference signal B −Y is the switch z4
bm is selected, and the color difference signal t< before IH is selected.
-y are simultaneously selected by the switch 24a, and after IH, the color difference signal RY at that time and the color difference signal B before IH
”-Yr is the switch 24a.

24b, each lotus is selected at the same time. In this way, the color difference signals R-Y, B-Y, which are thresholded every 51H by the line sequential switch 9 of the recording device, are delayed by the delay circuit 23 to become IH.
Previous color difference signals R-Y, B-Y.

The two types of parallel signals are then supplemented by each other and are continuous. The color difference signal RY synchronized in this way,
B - Y, blanking period waveform shaping circuit 25, 26 and NT
It reaches a mixer 28 via the SC encoder 27, where it is combined with the luminance signal Y to form the original video signal, and this video signal is outputted via the output terminal 29'.

At this time, the blanking period waveform shaping circuits 25 and 26 are circuits that remove the discrimination pulse 6 inserted in the blanking period for each IH and perform waveform shaping to return to the primary color difference signal waveform. The fcNTSC encoder 27 outputs color difference signals R-Y, B.
-Y modulated with color subcarrier (3,58MH7) respectively
This is used to create TSC color signals.

What is important in such a reproducing apparatus is to accurately synchronize the line-sequential color difference signals R-Y and B-Y. That is, the color difference signals R-Y, B-Y.

This is accomplished by accurately switching the synchronization switch 24. In this embodiment, the Q output of the flip-flop circuit 30 is Furthermore, the gate circuit 31 receives the discrimination signal extracting pulse 33 at the same time as the color difference signal 10 delayed by IH in the delay circuit 23, and the gate circuit 32
At the same time as the color difference signal 10 demodulated by the FM demodulator 22, a discrimination signal sampling pulse 33 is supplied to the FM demodulator 22, respectively. This discrimination signal extraction 9 pulse 33 is a pulse that rises at the same period as the IH so as to cover the discrimination pulse 6 in the vicinity of the position where the discrimination pulse 6 is added. Further, the gate circuits 3'l and 32 are ANI) gates. Therefore, among the IH-delayed color difference signals 10, the color difference signals B −Y,
The discrimination pulse 6a is extracted every 2H from . Furthermore, the discrimination/curse 6b is extracted every 2H from the color difference signal B-Y of the color difference signal 10 that is directly supplied to the gate 32 without passing through the delay circuit 23. Therefore, there is an IH phase difference between the discrimination pulses 6a and 6b. Second
FIG. 2(f) is a waveform diagram showing the discrimination pulse 6a, and FIG. 2(g) is a waveform diagram showing the discrimination pulse 6b. The flip-flop circuit 30 uses the discrimination pulse 6a as a set trigger pulse and the discrimination pulse 6b as a reset trigger pulse. Therefore, the output signal 34 of the clip-flop circuit 30 becomes a pulse that rises at the rising edge of the discrimination pulse 6a and falls at the rising edge of the discrimination pulse 6b, as shown in FIG. 2(h). With this Q output signal 34, the simultaneous switch 24 is set to 1! (It can be switched every time.

FIG. 3 is a block diagram showing a reproducing apparatus according to another embodiment of the present invention. This playback device uses the synchronization switch 240
Since the control system is changed and the other configurations are the same as the playback device shown in FIG. 1(b), the same parts are given the same numbers and redundant explanations will be omitted. As shown in FIG. 3, the clip-flop circuit 35 outputs a signal from the Q output terminal every time a pulse is supplied to the clock terminal C, provided that a pulse is supplied to the reset terminal l< and reset is performed. The state of the Q output signal 37 changes. The clock terminal C of this flip-flop circuit 35 receives, for example, a horizontal drive signal (1. D, is supplied, and the determination pulse 6b extracted by the gate circuit 36 is supplied to the reset terminal R. At this time, the gate circuit 36 receives the color difference signal 1 demodulated by the FM demodulator 22.
At the same time as 0, the discrimination signal extracting signal 33 is supplied, and thus the color difference signal HY, which is a component of the color difference signal 10.

The discrimination pulse 6b is extracted every 2H from .

The fourth factor (a) to FIG. 4(e) are horizontal drive signals H and D in order.
, , is a diagram showing the waveform of the 35 Q output signals 37 at the time of the discrimination pulse 6b and the flip-flop. As can be understood from these figures, the state of the Q output signal 37 of the clip-flop circuit 35 changes every time the horizontal drive signals H, IJ rise on the condition that the discrimination pulse 6b rises. The simultaneous switch 24 is switched by this Q output signal 37 for each IH.

In addition, although the above embodiment has been described with respect to the case of the NTSC system, the present invention is not limited to this, and, for example, the PAL system may be used. At this time, N 'f' SC encoder 27 is PA
It becomes an L encoder.

As specifically explained above with the embodiments, according to the present invention, in the recording system, a discrimination pulse for identifying one of the two types of color difference signals is added every horizontal scan, while in the regenerated yarn, the discrimination pulse is added to one of the two types of color difference signals. The pulse is extracted and the synchronization switch is switched every horizontal period based on this discrimination pulse or the output signal of the clip-flop circuit with the detection of this discrimination pulse as a condition. In addition to simplifying the circuit configuration, the synchronization switch can be switched accurately in a predetermined order after recovery, even if a burst error occurs, for example.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a recording device that implements an embodiment of the present invention, FIG. 1B is a block diagram showing a playback device thereof, and FIGS. h) is shown in Figure 1 (
a) and FIG. 1(b), FIG. 3 is a block diagram showing a playback device according to another embodiment, and FIGS. ) is a waveform diagram showing the waveform of each part. In the drawing, 6 is a discrimination pulse, 23 is a delay circuit, 24 is a synchronization switch, and 30.35 is a 7 lip-flop circuit. Patent applicant: Fuji Photo Film Co., Ltd. agent patent attorney
Shibu Mitsuishi (1 other person) He he he hetl: +8 0 ℃

Claims (3)

[Claims] (1) Two types of color difference signals are alternately selected every horizontal scanning period and made line sequential, and a carrier color difference signal obtained by modulating a carrier wave with this line sequential color difference signal and another carrier wave with a luminance signal. In a video signal recording method that multiplexes a carrier luminance signal obtained by modulating the color difference signal and records it on a magnetic recording medium, a discrimination pulse for identifying one of the color difference signals is added every horizontal scanning period to one of the color difference signals. A video signal recording/playback method characterized by the following. (2) Adding a discrimination pulse to identify one of the two types of color difference signals every horizontal scanning period, and
These two types of color difference signals are alternately selected every horizontal scanning period and made line sequential, and the carrier color difference signal obtained by modulating a carrier wave with this line sequential color difference signal and the other carrier wave are modulated with the luminance signal. In a video signal reproduction method in which the carrier video signal is multiplexed and recorded on a magnetic recording medium and the carrier video signal is reproduced, a color difference signal obtained by demodulating the carrier video signal and a color difference signal obtained by demodulating the carrier video signal are recorded on a magnetic recording medium. It has a synchronization switch that simultaneously selects another color difference signal that was previously demodulated and delayed for the same period, and also includes a color difference signal to which a discrimination pulse has been added among the color difference signals obtained by demodulating the carrier video signal, and this color difference signal. A flip-flop circuit is alternately set and reset using discrimination pulses extracted from a color difference signal obtained by delaying the signal by one horizontal scanning period, and the synchronization switch is alternately set and reset every horizontal scanning period by the output signal of this flip-flop circuit. A video signal reproduction method characterized by switching. (3) Adding a discrimination pulse to identify one of the two types of color difference signals every horizontal scanning period, and
Two types of color difference signals are alternately selected every horizontal scanning period and made line sequential, and the carrier color difference signal obtained by modulating a carrier wave with this line sequential color difference signal and another carrier wave are modulated with a luminance signal. In a video signal reproduction method for reproducing a carrier video signal recorded on a magnetic recording medium by multiplexing a carrier luminance signal obtained by a carrier video signal, a color difference signal obtained by demodulating the carrier video signal;
It has a synchronization switch that simultaneously selects another color difference signal that was demodulated before the horizontal scanning period and delayed for the same period, and also uses a discrimination pulse extracted from the color difference signal obtained by demodulating the carrier video signal as a reset input to control the horizontal scanning. A video signal reproducing method characterized in that the synchronization switch is alternately switched every horizontal scanning period using an output signal of a flip-flop circuit whose drive signal is a clock pulse.