JPS59168792A - Recording and reproducing device of secam system color video signal - Google Patents

Abstract

PURPOSE:To simplify circuit constitution by compressing the time axis of line sequential color difference signal FM-demodulating a carrier chrominance signal in the color video signal of the SECAM system at recording without simultaneous processing and frequency-modulating the color difference signal without simultaneous processing at reproduction. CONSTITUTION:A low pass filter 3 and a decoder 4 separate a luminance signal and a carrier chrominance signal from the SECAM system color video signal. The luminance signal is applied to an A/D converter 5 and RAMs 8, 9 and a signal subject to the time axis compression is extracted from a switch circuit 10. A line sequential color difference signal outputted from a switch circuit 13 is given to an A/D converter 14 and the color difference signal subject to the time axis compression is outputted from an RAM15. The switch circuit applies the signal subject to the time axis compression as above with time division multiplex and the result is recorded on a magnetic tape 26. The time division multiplex signal is demodulated by an FM demodulator 31 or the like at reproduction, a reproduced time division multiplex signal is obtained, the reproduced luminance signal subject to the time axis compression is obtained from a D/A converter 11 and a line sequential color difference signal restored with the time axis is obtained from a D/A converter 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 1 The present invention relates to a recording and reproducing device for SECAM color video signals, and in particular, time-division multiplexing after time-base compression of the luminance signal and color difference signal of the SECAM color video signal. This is frequency-modulated and recorded on a recording medium (e.g. magnetic tape).
The present invention relates to a recording and reproducing apparatus which performs FM demodulation of a frequency modulated wave recorded and reproduced, and then expands the time axis to obtain a reproduced color video signal output.

PRIOR ART The current color video recording/reproducing device (for example, V'
The mainstream recording and reproducing devices of I"R) are the standard method (N"r SC method, AL method or SECA method).
A luminance signal and a low-frequency converted carrier color signal are separated from the composite color video signal of M method), the luminance signal is frequency-modulated to become a frequency-modulated wave, and the carrier color signal is frequency-converted to a low-frequency range and converted to a low-frequency modulated wave. After converting into a carrier color signal, the frequency-modulated wave is frequency-division multiplexed and recorded, and at the time of reproduction, signal processing is performed in the opposite direction to that in the recording section.C Obtaining a reproduced composite color video signal that complies with the original standard method. It is well known that this is a recording and reproducing apparatus using a so-called low frequency conversion recording and reproducing method. Such a recording and reproducing device using the low frequency conversion recording and reproducing method is particularly suitable for application to consumer VTRs in which the recording and reproducing band is relatively narrow because the band of the luminance signal can be arbitrarily selected; The signal may be affected by fluctuations in the VTR's playback time axis,
■Only the luminance signal passes through the FM modulation/demodulation system, and since the pilot signal is not recorded or reproduced, there is less beat interference.Furthermore, ■The frequency-modulated luminance signal acts like a high frequency bias, improving the linearity of the carrier color signal. It has advantages such as being able to record data.

However, on the other hand, the above-mentioned recording and reproducing apparatus using the low frequency conversion recording and reproducing method is somewhat insufficient in achieving higher image quality due to the limited recording and reproducing band of the luminance signal and carrier color signal. Low frequency conversion carrier color signal is NTSC system or PAL
When recording a color video signal, a balanced modulation wave is used, and due to uneven contact between the tape and head, AM noise in the reproduced low-frequency conversion carrier color signal occurs, deteriorating the S/N (signal-to-noise ratio), and In a recording and reproducing apparatus that uses the so-called azimuth recording and reproducing method, in which two heads that record and reproduce adjacent video tracks are set at different azimuth angles to record and form video tracks without guard bands, the azimuth loss effect occurs. Since it is not sufficient for low frequency, the low frequency converted carrier color signal of the adjacent track is mixed into the reproduced signal as a crosstalk component. The phase of the color subcarrier frequency of the low-pass conversion carrier color signal is shifted approximately 900 times per horizontal scanning period (1) (for example, Japanese Patent Publication No. 56-9073, Japanese Patent Publication No. 55-32273), or There are problems such as the need for cross 1-1 countermeasure processing, such as inverting the phase of only the low frequency conversion carrier color signal of one of the adjacent video tracks every 1H.

Furthermore, when recording and reproducing an SC:C4V system color video signal using the above-mentioned azimuth recording and reproducing system recording and reproducing apparatus, the above-mentioned crosstalk countermeasures are necessary since the low-pass conversion carrier color signal is a frequency modulated wave. cannot be applied, but
Horizontal synchronizing signal recording positions are aligned and recorded in the direction (track width direction) perpendicular to the longitudinal direction of adjacent video tracks (so-called H-aligned recording), and low frequency conversion is a frequency modulated wave. If the modulation signal components of the carrier color number m are recorded and reproduced (in other words, the same type of color difference signal components), the modulation signal components of the carrier color m are almost the same. The frequency reproduced as crosstalk from the track is correlated with the color video signal components at one field interval, and since the modulated signal components are recorded side by side, the frequency of the reproduced track is low. The frequency is approximately the same as the frequency of the range-transformed carrier color signal, and since the frequency of the beats generated by both signals is close to zero, there is almost no effect of Talostalk.

However, when reproducing a magnetic tape with a 1 to easy pattern that is not recorded in an H arrangement, the beat frequency due to crosstalk from adjacent tracks is different due to the difference in the carrier frequency of the SECAM system low-frequency conversion carrier color signal of adjacent tracks. This problem extends to high frequencies and appears as noise on the reproduction television screen, making it impossible to apply the azimuth recording and reproduction method.

On the other hand, recent dramatic advances in semiconductor technology, precision processing technology, and small component technology have made it possible to improve the image quality of recording and reproducing devices and to make devices smaller and lighter. Reducing the cassette size and drum diameter has a major impact on making devices smaller and lighter, and in order to secure the necessary recording time for small cassettes, it is necessary to slow down the tape running speed. In order to obtain high image quality in compact and lightweight recording and reproducing apparatuses, a new recording and reproducing method other than the above-mentioned low frequency conversion recording and reproducing method has come to be required.

Therefore, various recording and reproducing methods have been proposed to meet the above requirements, and one of them is
Two types of color difference signals obtained by M demodulation are time-axis compressed and the luminance signal is also time-axis compressed, these signals are time-division multiplexed, and this time-division multiplexed signal is frequency-modulated and recorded on a recording medium. There was a recording/playback device configured to perform the reverse signal processing during playback to that during recording to obtain a playback output of the original standard color video signal (for example, see Japanese Patent Application Laid-Open No. 53-5926). . This recording/reproducing device takes into consideration the difference between the bands of the luminance signal and the color difference signal, and uses the 1H period to transmit the color difference signal, which is a signal with a narrower band, within the horizontal blanking period. The time axis of the chrominance signal transmitted within the 1H period is compressed to approximately 20% of the 1H period, and the luminance signal is compressed in the same bandwidth as the time axis compressed chrominance signal, which is advantageous from the viewpoint of bandwidth utilization. The time axis is compressed and transmitted during approximately 80% of the 1H period, and the two color difference signals are time-division multiplexed as line sequential signals that are transmitted alternately from 1) to 1@. feed the modulator,
The output signal of this FM modulator is recorded on a magnetic tape, etc., and during playback, signal processing is performed in the opposite direction to that during recording to obtain a reproduced color video signal (hereinafter referred to as the timeplex method). ).

FIG. 1 shows an example of the signal waveform of the above-mentioned time division multiplexed signal. For example, in a PAL or SECAM composite color video signal with a field frequency of 50 Hz and 625 scanning lines, 11-1 is 64 μs, the horizontal blanking period is 12 μs, and the remaining video period is 52 μs. The luminance signal and the carrier color signal are transmitted (excluding the color burst signal), of which the luminance signal is transmitted for 64 μs,
The carrier color signal is demodulated to produce two color difference signals, each of which is time-base compressed in a period of about 20% of 64 μs, and a time-base compressed luminance signal and a time-base compressed luminance signal are obtained. The time-domain compressed color difference signal is time-division multiplexed as shown in FIG. 1, and the time-domain compressed color difference signal is transmitted line-sequentially. Furthermore, as shown in FIG. 1, both time axis compressed signals are transmitted at approximately 50 μs to 60/is, but the period of one day is 64 μs, and the horizontal synchronizing signal 1-1 is transmitted during the remaining period (blanking period). 1.5 sync and the reference level of the one-color signal are transmitted.

Such time division multiplexing (according to the time-plex method that transmits No. 8, there is no period in which the luminance signal and the color difference signal are transmitted simultaneously, so the NT'SC method or l) A L
There is no mutual interference or moiré between the luminance signal and color difference signal, which can occur when the luminance signal and carrier chrominance signal are band-sharing multiplexed and transmitted, as in the case of a color video signal. system, PAL system and SE
Even if a CAM color video signal is recorded and played back on tracks that are not arranged in H by a recording/playback device using the azimuth recording/playback method, the time division multiplexed signal will have a large azimuth loss effect on adjacent tracks. Since the signal is recorded in the form of a frequency-modulated wave signal obtained by frequency modulating a high-frequency carrier wave, almost no crosstalk occurs due to the azimuth loss effect, and the above-mentioned crosstalk countermeasures are unnecessary. Provides high-quality playback image quality.

Furthermore, the above-mentioned time-domain compressed luminance signal and time-domain compressed color difference signal, which are based on the time-plex method, have an energy distribution in which the energy is high in the low frequency band and small in the high frequency band. Since the signal format is suitable for modulation, the modulation index is thick (the S/N ratio can be significantly improved, and when the time axis is further expanded, reproduction time axis fluctuations can be almost completely removed). From the above, the reproduced image quality can be significantly improved compared to that of the low frequency conversion recording and reproducing method.

Problems to be Solved by the Invention Incidentally, conventional timeplex recording and reproducing apparatuses do not process standard color video signals during recording in order to be compatible with any of the N'T SC, PAL, and SFCAM systems. The carrier color signal is demodulated, or the three primary color signals from a color television camera, etc.
and <B-Y)) are alternately switched every 111 to perform time axis compression on the line-sequential color difference signal, and during playback, the time axis compression is performed. The time axis is expanded to 19. The reproduction line sequential color difference signal is 11.
-1 delay circuit to one contact of each of the two switches, and apply a reproduction line sequential color difference signal directly to the other contact of these two switches to interlock these two switches. By switching every 1H, 2
It had a circuit section for separately and successively extracting two types of reproduced color difference signals from the common contacts of the two switches.

However, when recording and reproducing a SECAM color video signal using the time flex method, the carrier color signal in the SECAM color video signal is a color difference signal (R
7Y ) obtained by frequency modulating the first carrier wave.
The frequency modulated wave and the second frequency modulated wave obtained by frequency modulating the second carrier wave with the color difference signal (B-Y) are alternately synthesized and transmitted in time series every day. It goes without saying that the color difference signals (RY) and (B-Y) obtained by FM demodulating the carrier color signal are already line sequential color difference signals.

For this reason, in the conventional recording and reproducing apparatus described above, SEC
When recording an AM system color video signal, the demodulated line-sequential color difference signal is passed through a circuit for synchronizing it and then supplied to the switch circuit section that obtains the line-sequential color difference signal.On the other hand, during playback, the line-sequential color difference signal is synchronized from the reproduced line-sequential color difference signal. A circuit section for obtaining a line-sequential color difference signal again from the two reproduced color difference signals passed through a circuit section consisting of two switches and a 1H delay circuit for obtaining two color difference signals is required, which requires more circuitry than necessary. There was a problem that the configuration was complicated.

Therefore, the present invention compresses the time axis of the line-sequential color difference signal obtained by FM demodulating the carrier color signal in the SECAM system video signal without synchronizing it during recording, and expands the time axis during recording. The object of the present invention is to provide a 5ECA'M color video signal recording and reproducing apparatus which solves the above problems by frequency modulating the reproduction line sequential color difference signals obtained by the reproduction line without synchronization.

Means for Solving the Problems The present invention provides separation means for separating a SECAM system color video signal into a brightness signal, a carrier color signal, and a time signal of the luminance signal extracted from the separation means. A first 1-hour shaft compression means for compressing the shaft, and the l taken out from the separation means.
! a second time-base compression means for demodulating the color feeding polarized color signal M and directly compressing the time-base of the line-sequential color difference signal obtained thereby without converting it into a simultaneous signal; and the first and second time-bases. Ryokawa Riki (No. H) is supplied as a compression means, and the two types of time-axis compressed color difference signals are alternately processed every horizontal scanning period, and the - time-axis compressed color difference signals are converted into time-axis compressed luminance signals within one horizontal scanning period. means for time-division multiplexing with the signals, means for frequency modulating the time-division multiplexed signal from the time-division multiplexing means and recording it on a recording medium, and FM demodulating the time-division multiplexed signal reproduced from the recording medium. reproducing means for obtaining a reproduced time division multiplexed signal;
a first time-axis expanding means for obtaining a reproduced luminance signal by time-axis expanding the reproduced time-division multiplexed signal by the amount of time-axis compressed by the first time-axis compression means; a second time axis expansion means for obtaining a reproduction line sequential color difference signal by expanding the time axis by the amount of time axis compression by the time axis compression means; The apparatus is comprised of a means for obtaining a carrier color signal conforming to the SFCAM system, and each embodiment thereof will be described below with reference to FIG. 2 and the following drawings.

Embodiment FIG. 2 shows a block system diagram of a first embodiment of the apparatus of the present invention, and FIG. 3 shows a processing system diagram of an embodiment of the main part of FIG. First, the operation during recording will be explained. In Figure 2,
S [CAMh color video signal (
This is a composite video signal) is fed through a switch circuit 2 connected to terminal 1 to a low-pass filter 3, where the H-degree signal is separated while being fed to a decoder 4.Decoder 4 is the size block 40 to 4 shown in Figure 3.
First, a bandpass filter 40 filters S.
The carrier color signal, which is a frequency modulated wave, is separated and extracted from the ECAM color video signal, and passed through a bell filter 41 and a [M demodulator 42, respectively, to produce a color difference signal (RY) and (B
-Y) are alternately synthesized in 18ffi in a time-series manner to generate a line-sequential color difference (r.i. When the color par signal conforms to the SECAM method as shown in Figure (A), the FM demodulator 4
2, a line-sequential color difference signal having a waveform as shown in FIG. 2(B) is extracted.

As can be seen from FIG. 4(A), this line-sequential color difference signal is
The DC level b1 of the achromatic color part (non-modulated carrier part) with a width of 4 to 9 μs on the back porch during the one-day period when the color difference signal (B-Y) is transmitted, and the color difference signal @ (R-Y) is transmitted. 4.9μs in the bank pouch within the next 1H period
DC level b of the achromatic part of the width (unmodulated carrier part)
2, there is a certain value difference between them. This is because the color subcarrier frequency of the carrier color signal is different from 4.25 MH7 on the color difference signal @ (B-Y) transmission line and 4,406 MHZ on the color difference signal (R-Y) transmission line. be.

The line sequential color difference signal as shown in FIG. 4(B) is supplied to terminal A of the switch circuit 43 and sample and hold (hereinafter abbreviated as rs/HJ) circuits 46 and 47, respectively. The S/H circuit 46 is a circuit that samples and holds the level of the achromatic color portion of the two types of color difference signals, and here samples and holds the level of the achromatic color portion within the bank porch period of the color difference signal (B-Y). switch circuit 43
Supplied to the terminal port.

The above switch circuit 43. The switching signals and sampling hold pulses supplied to the S/H circuits 46 and /17 are supplied to the circuit portions shown in the same figure other than the decoder 4 shown in FIG. 3 and the encoder 34 described later (this circuit portion is shared during recording and reproduction). , supplies a signal to the decoder 4 during recording,
During reproduction, a signal is supplied to the encoder 34, but is not shown in FIG. 2 for the sake of convenience. That is, a rectangular wave a (not necessarily a symmetrical rectangular wave) as shown in FIG. 5(A) that is phase-synchronized with the horizontal synchronizing signal enters the input terminal 48 shown in FIG. 4'9. A rectangular wave a is supplied to the S/H pulse generation circuit 50 and the blanking pulse generation circuit 54, respectively. Flipper 49 divides the frequency of the rectangular wave a by 1/2 to generate the J rectangular wave shown in FIG. While the signal discrimination pulse is supplied as a signal discrimination pulse, S
/H pulse generation circuit 50. The signal is supplied to a line discrimination circuit 53 and a DC shift pulse generation circuit 55, respectively.

S/1'' pulse generation circuit 50 generates a rectangular wave a and a 5th wave
Two types of S/H pulses C as shown in Figures (C) and (D)
and d, and supplies the S/H pulse C to the S/H circuit 46, which samples and holds the achromatic portion within the back porch period of the transmission line of the color difference signal (B-Y). At the same time, 8/'H pulse d is applied to the S/H circuit 47.
Here, the achromatic portion within the back porch period of the transmission line of the color difference signal (RY) is sampled and held. The comparator 51 compares the levels of the re-output signals of the S/1'' circuits 46 and -47, and supplies a signal based on the comparison result to the line discrimination circuit 53 through the switch circuit 52 connected to the terminal R.

Now, the square waves a, b, S/H pulses C and d are the fifth
The color difference signal (B-Y) is output from the FM demodulator 42 during the 1H period when the rectangular wave is at a low level, with the phase relationships shown in Figures <A>, (B'), (G), and (D), respectively. is output, the output DC level of the S/H circuit 47 is the DC level of the achromatic color part of the color difference signal (RY), so it is higher than the output DC level of the S/1-1 circuit 46. The prices are also getting higher. Therefore, the output of the comparator 51 at this time becomes, for example, the [''- level, and the line discrimination circuit 53 is prevented from outputting a reset pulse, so that the flip-flop 49 is not reset.

However, in a platform where the color difference signal (R-Y) is output from the FM demodulator 42 during the 1H period when the rectangular wave 1) is at a low level, the output of the comparator 1 becomes, for example, a high level, A reset pulse is generated from the line discrimination circuit 53 to reset the four knobs of the flip 70. As a result, the relationship is restored such that the color difference signal (B-Y) is output during the 11'' period when the output rectangular wave of the flip-flop 49 is at a low level. As a result of the above, the 1H square line of the carrier color signal of the SIzCAM method is determined.

On the other hand, from the blanking pulse generation circuit 54, a rectangular wave e as shown in FIG. is supplied as a switching signal to During the period when the rectangular wave e is at a high level, the switch circuit 43 passes and outputs the input color difference signal at the terminal A to the next stage DC shift circuit 44, and when the rectangular wave e is at a low level, it passes the input color difference signal at the terminal port (i.e., the color difference signal ( The achromatic color level of B-Y) is selectively outputted and supplied to the DC shift circuit 44. The DC shift circuit 44 performs a DC shift on the line-sequential color difference signal from the switch circuit 43 in response to the pulse f shown in FIG. and (B-
cancels the DC level difference with Y). DC shift circuit 44
The output line sequential color difference signals are supplied to the terminal R of the switch circuit 13 shown in FIG. 2 through the de-emphasis circuit 45. Note that line discrimination may be performed using the frequency before demodulation of the achromatic color portion within the back porch period.

Returning to FIG. 2 again, the low-pass filter 3 extracts the luminance signal separated from the input SECAM color video signal, while the decoder 4 extracts the luminance signal separated from the input SECAM color video signal as described above. A line-sequential color difference signal is extracted which has been subjected to FM demodulation and in which the DC level difference in the achromatic color portion has been canceled. The above luminance signal is sent to the sync separation circuit 6, where the sync signal is separated and extracted, and the sync signal is separated and extracted.
After being subjected to real-analog to digital conversion by the D converter 5, it is supplied to random access memories (RAM>8 and 9, respectively).The control pulse generator 7 is supplied with a synchronization signal from a synchronization separation circuit 6j. The rectangular wave is supplied as a color difference signal discrimination pulse, and the generated control pulses are supplied to converter 5, 14, and DA converter 11 and 16, respectively. It generates wide horizontal synchronization signals and various pulses, and also uses RAM8.9 and 1.
[Write to No. 5 I] Rack read clocks are generated and output at predetermined timing and at a predetermined repetition frequency.

'However, the control pulse generator 7 is RAM8.
And 9 -h is supplied with a write clock pulse of, for example, 8 MHz to write one day's worth of luminance signals transmitted in a video period of 52 μs into one of the RAMs, and at the same time, read out at, for example, 10 M, Hz. clock pulse, 1
1H1 minute (
Immediately after the transmission of the time-base compressed color difference signal (52 μs) is completed, the signal 1 is supplied to the other RAM and stored in the other RAM.
The luminance signal for 1H before H is read out. This RAM8
The read operation and write operation of RAMs 8 and 9 are alternately switched every 1H, and the switch circuit 10 on the output side of RAMs 8 and 9 switches between the RAMs 8 and 9 which are performing the read operation using control pulses from the control pulse generator 7. Since the output signal 9 is selectively outputted, the luminance signal 415 time-axis compressed is intermittently extracted from the switch circuit 10 without any loss of information. This time-base compressed luminance signal is digital-to-analog converted by a DA converter 11 and supplied to a switch circuit 12 .

On the other hand, the line sequential color difference signal outputted from the switch circuit 13 is supplied to the RAM 15 after being analog-to-digital converted by the AD converter 14 .

The RAM 15 writes line-sequential color difference signals transmitted during a 52-μs video period within 1 H (= 64 μs) using a write clock pulse of, for example, 2MHI in the controller 1-roll pulse generator 7J. For example, 1.6 μs), then read out the color difference signal time-axis compressed to 115 using the readout clock pulse of IOMH2 (therefore, one readout period is 1
0.4 μs). As a result, when the SIE CAM color video signal (color par signal) shown in FIG. 4(A) is input to the input terminal 1, the DA converter 16 outputs a waveform as shown in FIG. 4(C). The time-base compressed line sequential color difference signals are extracted and supplied to the switch circuit 12 and the input terminal 57 of the encoder 34. However, the encoder 34 is inactive during recording. In FIG. 4(C), (R-Y)c is the time-axis compressed color difference signal (R-Y).
(B-Y), and (B-Y)C shows the time-axis compressed color difference signal (B-Y), which is the line-sequential color difference signal (B) obtained by FM demodulation in the decoder 4. 1H for the signal
It has been delayed.

This is because the color difference signals for one day are read out after reading them in the RAM 15.

The switch circuit 12 receives the above-mentioned time-domain compressed line-sequential color difference signal, the time-domain compressed luminance signal having the waveform shown in FIG. Approximately 4 μ as shown in Figure 4 (D>
Switching control is performed to time-division multiplex the s-width horizontal synchronization signals based on the output control pulses of the device 7, respectively. The time division multiplexed signal taken out from this switch circuit 12 is a burst signal for discrimination.
The determination burst signal generated by the determination burst signal generation circuit 17 based on the output control pulse of the control pulse generator @7 is added thereto. This discrimination burst signal is a burst signal for discriminating the transmission line of the color difference signal (B-Y) and (R-Y). For example, a single frequency signal of 1.5 MHz is the color difference signal (B-Y). and (R-Y) - the fourth color difference signal (R-Y here).
Horizontal ++, il Jll shown in Figure (D) (corresponding to the generation period of LiM) is generated as shown in Figure (F).

In this way, when a SECAM color video signal such as the color bar signal shown in FIG. 4(A) and FIG. 6(A>) is input to the input terminal 1, the determination burst signal
From the J adding circuit 18, as shown in FIG. 6(B), I
I iJ3 The horizontal synchronization signal is determined by parse 1 ~ signal + every 3 seconds.
Also, the horizontal synchronization signal, the color reference level (the DC level of the achromatic part of the - color difference signal), and either the time axis compressed color difference signal (R-Y)C or (B-Y)c, The time-domain compressed luminance signal is time-division multiplexed, and the time-domain compressed color difference signal is extracted as a time-division multiplexed signal that is transmitted line-sequentially. This time division multiplexed signal is sent to the pre-emphasis circuit 19. White peak level clip circuit 20.
Clamp circuit 21. F, M modulator 22, high-pass filter 2
3 and a recording amplifier 24, the signal is supplied to the recording head 25 through a known recording signal processing circuit,
As a result, the information is recorded on the magnetic chip 126.

Next, I will explain the operation during playback.At this time, switch circuits 2, 13, and 52 are connected to the respective terminals. Connected to the P side.

A time division multiplexed signal recorded on the magnetic tape 26 in the form of a frequency modulated wave is reproduced by the reproduction head 27, and this reproduced frequency modulated wave is transmitted to the reproduction amplifier 28. Equalizer 29. High pass filter 30. A reproduction time division multiplexed signal is generated through a known reproduction signal processing circuit comprising an FM demodulator 31 and a de-emphasis circuit 32. This reproduced time-division multiplexed signal passes through a switch circuit 2 and a low-pass filter 3 connected to a terminal P, and then to an AD converter 5. The signal is supplied to the synchronous separation circuit 61 and the discrimination burst signal detector 33, and is also supplied to the AD converter 14 through the switch circuit 13 connected to the terminal P. AD converter5. RAM
8 and 9, a switch circuit 10, and a DA converter 11, the circuit unit generates a reproduced luminance signal whose time axis is expanded and returned to the original time axis based on the output signal of the control pulse generator 7. Here, when one of the RAMs 8 and 9 is performing a write operation on the time-base compressed luminance signal of the reproduced time division multiplexed signal, the other one is performing a read operation, and r< A M 8 and 9 are written every 11-1. The repetition frequency of the write clock pulse is, for example, 10 MH2, and the repetition frequency of the read L]futters is, for example, 8M
HZ, so I want the time axis to be extended to 5/4'? l
In other words, the time axis has been expanded by the amount of interplane axis compression.

The reproduced luminance signal is taken out alternately every 1H from ΔM8 and 9.

On the other hand, AD converter 'I'4, RAM 15 and DA
The circuit section consisting of the converter 16 stores the time axis compressed color difference signal in the reproduced time division multiplexed signal into the RAM 15 based on the output signal of the device 7, and then performs a read operation to return the time axis to the original position. A line-sequential color difference signal is obtained. That is,
For example, a digital signal of a reproduction time axis compressed color difference signal is written into the RAM 15 using a 10 MHz write clock pulse, and a 5 MHz read clock pulse is used to write a reproduced time axis compressed color difference signal.
The digital signal of the reproduction line sequential color difference signal whose time axis has been expanded twice and whose time axis has been restored is read out. The read digital signal is converted into a reproduction line sequential color difference signal through the DA converter 16 and then supplied to the input terminal 57 of the encoder 34. Further, the 1.5 MH2 discrimination burst signal is detected by the discrimination burst signal detector 33 and supplied to the input terminal 58 of the encoder 34 .

The encoder 34 is not shown in FIG. 3 and is composed of blocks 59 to 67 and the like. In the same figure, the reproduced line sequential color difference signal inputted to the input terminal 57 is transmitted to the pre-emphasis circuit 59.
is supplied to the DC shift circuit 60 through. During this reproduction, a 1H cycle rectangular wave a as shown in FIG. supplied to Therefore, l-
The current shift pulse generating circuit 55 generates and outputs the pulse f shown in FIG. ) is supplied as a shift pulse to the DC shift circuit 60, and the amphibian line sequential color difference signal has a DC level at each line of color difference signal (R-Y) and ([3-Y). The difference is given. This DC level difference is transmitted to the output terminal of the FM modulator 62 (described later), and the color difference signal (
The carrier frequency of the transmission line of [i-Y) is 4,25
M HZ is a DC level difference such that the carrier frequency of the color difference signal (RY) transmission line is /1,406 MH2.

The reproduced line sequential color difference signal to which the above DC level difference has been added by the DC 1-circuit 60 is supplied to the clamp circuit 61, where the signal from the clamp pulse generating circuit 69 as shown in FIG.
After being clamped at the achromatic part of the color difference signal (B-Y) by the 2H pulse h as shown in +-1>, F
The signal is supplied to the M modulator 62, where it is frequency modulated. As a result, a carrier color signal, which is a frequency modulated wave that substantially complies with the SECAM method, is extracted from the FM modulator 62 and supplied to the FM demodulator 63 and the low-pass filter 65 (note that this carrier color signal is The signal also has a color subcarrier in the horizontal synchronization signal portion, so it is not completely compliant with the SECAM system.)

The FM demodulator 63 demodulates the above carrier color signal and sends it to S
The color difference signal (B
-Y) Clamp pulse generation circuit 6
The signal is sampled and held by the output signal generator 9 and fed back to the FM modulator 62. This stabilizes the oscillation frequency of the FM modulator 62. Furthermore, the low-pass filter 65 removes unnecessary high-frequency components from the carrier color signal, and then supplies the signal to a blanking circuit 67 through a bell filter 66 . The blanking circuit 67 generates a low level period of the rectangular wave e shown in FIG. ) blocks the passage of the reproduced carrier color signal from the bell filter 66 and generates a rectangular wave e.
The reproduced carrier color signal is passed only during the high level period of .

At this time, a carrier color signal conforming to the SECAM system is taken out from the blanking circuit 67 to the output terminal 70.

In addition, during this reproduction, the detection burst signal detection output for discrimination of 21-1 cycles is supplied from the input terminal 58 to the line discrimination circuit 53 via the switch circuit 52.

When operating normally, the above detection output is present.
(Since the rectangular waveform is at a low level when
If there is a malfunction, the rectangular wave is at a high level when the detection output is present, so in this case, a reset pulse is generated from the line discrimination circuit 53 to reset the flip-flop 49. As a result, when a malfunction occurs, normal operation is restored.

SEC taken out from the output terminal 70 of the encoder 34
The reproduced carrier color signal conforming to the AM system is supplied to the mixing circuit 35 shown in FIG. After being converted into a reproduced color video signal conforming to the standard, it is output to the output terminal 36.

In this way, according to this embodiment, during recording, the SECAM
System The line-sequential color difference signal obtained by FM demodulation after separation from the color video signal is processed and recorded as is without converting it to a simultaneous signal, and during playback, the reproduced line-sequential color difference signal is converted into a continuous simultaneous signal. Since a reproduced carrier color signal conforming to the SECAM system can be obtained without any trouble, the circuit configuration can be simplified compared to the conventional device.

Next, a second embodiment of the device of the present invention will be described.

FIG. 7 shows a block system diagram of a second embodiment of the device of the present invention, and FIG. 8 shows a block system diagram of an embodiment of the main part in the block system shown in FIG. 7. In figure 8,
Components that are the same as those in FIGS. 2 and 3 are designated by the same reference numerals.
The explanation will be omitted. In this embodiment, the decoder 72 does not have a DC shift circuit as shown in FIG. 8, and the encoder 76 does not have a DC shift circuit, so the line-sequential color difference The feature is that the signal is transmitted, recorded and reproduced with a difference in DC level, without performing a DC shift of the signal. Therefore, in this embodiment, the discrimination information between the color difference signals (R-Y) and (B-Y) is transmitted as the difference between the DC levels, and there is no need to send a specific discrimination signal.
The circuit becomes simpler than the first embodiment.

In this embodiment, in J3, the color reference level in the time-division multiplexed signal shown in FIG. Since the line-sequential color difference signal or rIj raw time multiplexed signal taken out from the decoder 72 is input to the clamp circuit 74 shown in FIG. Only the color reference level of the transmission line of the signal (RY) or (B-Y) is clamped. The clamp pulse supplied to the clamp circuit 74 via the terminal 75 is generated as follows.

First, during recording, the line-sequential color difference signal taken out from the FM demodulator 42 in the decoder 72 shown in FIG. The DC level is S/l-(
The circuits 46 and 47 alternately sample and hold the sample every day, and the comparator 51 compares the levels of the held voltages. Thereafter, by the same operation as in FIG. 3, the clamp pulse generation circuit 69 to which the output signal of the flip-flop 49 is supplied transmits one predetermined color difference signal, as shown in FIG. 5(H). A 2H cycle clamp pulse h which remains at a high level for a period corresponding to the achromatic portion of the line is taken out and supplied to the clamp circuit 74 via a terminal 75.

During reproduction, the switch circuit 77 is switched to the terminal P side, and the reproduction line sequential color difference signal taken out from the pre-emphasis circuit 59 in the encoder 76 shown in FIG. 8 is supplied to the S/H circuits 46 and 47. , the color reference levels thereof are each rimple-held. As a result, a clamp pulse hh< is generated by the clamp pulse generating circuit 69 in the same manner as during recording, and is supplied to the clamp circuits 61 and 74, respectively. The clamp pulse generation circuit 69 can be used both during recording and during reproduction. Further, the input signals to the S/H circuits 46 and 47 may be the output line sequential color difference signals of the de-emphasis circuit/15 during recording, and may be the manually reproduced line sequential color difference signals of the pre-emphasis circuit 59 during reproduction. During playback, color difference signals (R-Y) and (B-Y)
Since the line-sequential color difference signal is reproduced while maintaining the DC level difference of each achromatic color part at a predetermined constant value, there is no need to perform a DC shift in the encoder 76, and the signal is directly supplied to the 2M modulator 62. In particular, a carrier color signal conforming to the SECAM system is obtained at the output terminal 70.

Application Example An application example in which either the recording system or the reproducing system of the apparatus of the present invention is used can also be considered. In other words, when only the recording system of the apparatus of the present invention is used, instead of supplying the reproduction line sequential color difference signal extracted from the DA converter 16 to the encoder 34 or 76, a carrier color signal conforming to the PAL system is supplied. It can also be supplied to a generating encoder to obtain a reproduced PAL color video signal, or it can be supplied to a matrix circuit to obtain a reproduced output of three primary color signals of R, G, and B. On the other hand, if only the reproduction system of the device of the present invention is used and the recording system has the same configuration as the conventional device, for example, a PAL color video signal is input to the recording system of the conventional device, and the carrier color signal is demodulated and obtained. A line-sequential color difference signal is generated from the (R-¥) and (B-Y) color difference signals, which are recorded using the time plex method, and the reproduced signal is supplied to the encoder 371 or 76 to generate a carrier color signal compliant with the SECAM method. It is also possible to generate this signal and output it as a reproduced color video signal using the SECAM system.

Effects As described above, according to the present invention, during recording, the line-sequential color difference signal obtained by FM demodulation after being separated from the SECAM color video signal is processed and recorded as it is without converting it into a simultaneous signal, and during playback. The system obtains a reproduced carrier color signal conforming to the SECAM method without converting the reproduced line-sequential color difference signal into continuous simultaneous signals. Also, the achromatic part of the line-sequential color difference signal obtained by 1- to 1 demodulation (unmodulated key A transmitted within a certain period in the back porch)
Aria demodulated signal component), color difference signal (R-Y) and (
If recording and playback is performed while maintaining the relative DC level difference in the image transmission line (B-Y),
It has the advantage of being able to have a simple and inexpensive circuit configuration.

[Brief explanation of drawings]

Fig. 1 is a waveform diagram showing an example of a time division signal of 1J3L in the time plex system, and Fig.
Fig. 3 is a J block system diagram showing an example of the main part of the block system shown in Fig. 2; ) to (+-1) and FIGS. 6<A) and (B') are signal waveform diagrams for explaining the operation of the device of the present invention, respectively, and FIG. 7 is a block system diagram showing a second embodiment of the device of the present invention, FIG. 8 is a block system diagram showing an embodiment of the main part of the block system shown in FIG. 7. 1...SECAM color video signal input terminal, 4.
72... Decoder, 5, 14... ΔD converter, 7° 73... Control pulse generator, 8, 9° 15
...Random access memory (RAM), 11.
16... DA converter, 12... switch circuit, 17
...Burst signal generation circuit for discrimination, 18...Burst signal addition circuit for discrimination, 21, 61.74...Clamp circuit, 22.62...FM modulator, 26...Magnetic tape, 31 .42.63...FM demodulator, 33...
- Burst signal detector for discrimination, 34.76... Encoder, 44.60... DC shift circuit, 57... Reproduction line sequential color difference signal input terminal, 58... Burst signal input terminal for discrimination, 70 ...Reproduction transport color signal output terminal.

Claims (1)

[Claims] (1) separation means for separating a SECAM color video signal into a luminance signal and a carrier color signal; a first time axis compression means for compressing the time axis of the luminance signal extracted from the separation means; A second step for FM demodulating the carrier color signal taken out from the separation means and directly time-base compressing the line-sequential color difference signal obtained thereby without converting it into a simultaneous signal.
, and both output signals of the first and second time axis compression means are supplied, and two types of time axis compressed color difference words are alternately per horizontal scanning period and are compressed in one horizontal scanning period. means for time-division multiplexing each of the time-axis compressed color difference signals and one time-axis compressed color difference signal within 191 intervals, and frequency-modulating the time-division multiplexed signal from the time-division multiplexing means and recording it on a recording medium. means for performing FM demodulation of the time division multiplexed signal reproduced from the recording medium to obtain a reproduced time division multiplexed signal; and time axis compression by the first time axis compression means from the reproduced time division multiplexed signal. a first time axis expansion means to obtain a reproduced luminance signal by expanding the time axis by the time axis, and a first time axis expansion means for obtaining a reproduced luminance signal by expanding the time axis by the time axis compressed by the second time axis compression means from the reproduced time division multiplexed signal, and sequentially reproducing the It is characterized by comprising a second time axis expansion means for obtaining a color difference signal, and a means for frequency modulating the reproduced line sequential color difference signal without converting it into a simultaneous signal to obtain a carrier color signal conforming to the SECAM system. SECA
Recording and reproducing device for M system color video signals. ■ The time axis is compressed by the second time axis compression means;
The line-sequential color difference signal, which is formed by combining two types of color difference signals in a time-series manner, is characterized in that the DC level difference between each achromatic color portion of adjacent color difference signals is maintained constant during recording and reproduction. A recording and reproducing apparatus for SIECAM color video signals according to claim 1.