JPS5894291A - Recording and reproducing device of secam (sequential color and memory) color video signal - Google Patents

Abstract

PURPOSE:To easily record and reproduce an SECAM color video with high density, by converting a color video signal to a PAL color video signal, and utilizing a low band converting type recording and reproducing device for the PAL color video signal. CONSTITUTION:An SECAM color video signal to be recorded is supplied to a converting circuit 2 for recording, and is converted to a PAL color video signal. As for an output of this circuit 2, a luminance signal Y is FM-modulated in the high band side, and a chrominance signal Cp is frequency-converted in the low band side. Subsequently, a composite signal of the FM-modulated luminance signal, and the frequency-modulated and phase-controlled chrominance signal is recorded in heads 5A, 5B. On the other hand, reproducing outputs of the heads 5A, 5B are sent to a processing circuit 6 for reproduction, through a switch 4, and the FM-modulated luminance signal and the chrominance signal are separated. Subsequently, the separated luminance signal is FM-demodulated, phase of the separated chrominance signal is restored to its original recording state in accordance with control of a processing circuit 3 for recording, and a color signal is obtained through a filter for eliminating a crosstalk.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording and reproducing apparatus for SECAM color video signals, and in particular, to an apparatus capable of recording SECAM color video signals at high density.

A method for recording NTSC color video signals and PAL color video signals with high density has already been proposed. F on the side
M modulation, the carrier color signal is frequency-converted to the lower frequency side, and in the case of recording an NTSC color video signal, the phase of the carrier color signal is changed to every t tracks as shown in FIG. 1, which is continuous in TA, and reversed every l line in the remaining every other track Ta;
According to this, regarding the luminance signal during playback,
Since it is FM modulated and has a large azimuth loss, there is almost no crosstalk from adjacent tracks. On the other hand, since the carrier color signal has been low-pass converted and has a small azimuth loss, crosstalk from adjacent tracks occurs, but by restoring the phase of the reproduced carrier color signal to the state before recording. Both when playing back the track TA and when playing back the trunk TB, the phase of the original carrier color signal So from that track is continuous, as shown in FIG. Since the phase of the component Sc is inverted every l line, by passing the restored carrier color signal through a comb-shaped filter having a delay line with a delay time of l lines, the a stalk component Sc is removed, and the original Only the carrier color signal So can be extracted.

However, the carrier color signal of the 5ECAIVi color video signal is not AIVI modulated like the carrier color signal of the NTSC color video signal or the PAL color video signal, but is FM modulated. 3. By the way, both the SECAM color video signal and the PAL color video signal have a field frequency of 5OH2, a line frequency of /ta, and 62kHz.
2, the only difference is the aspect of the carrier color signal.

Focusing on this point, the present invention converts the SECAM color video signal fjr into a PAL color video signal or a signal similar to this, thereby utilizing a low frequency conversion type recording and reproducing device for PAL color video signals. , SECAM color video signals can be easily recorded at high density.

FIG. 3 schematically shows the overall configuration of an example of the recording/reproducing apparatus of the present invention, in which a SECAM color video signal to be recorded is supplied to an input terminal l.

This SECAM color video signal to be recorded is supplied to a recording conversion circuit and converted into a PAL color video signal. That is, in the recording conversion circuit 2, the luminance signal Y and the carrier color signal Cs are separated from the input SECAM cube video signal, and the luminance signal Y is output as is, but the carrier color signal C8 is converted into a PAL color video signal. is converted into a carrier color signal Cp and taken out as an output.

The luminance signal Y and the carrier color signal Cp, that is, the PAL color video signal obtained from the recording conversion circuit 3 are supplied to the recording processing circuit 3. The recording processing circuit 3 corresponds to the recording system of a low frequency conversion type recording and reproducing device for PAL color video signals, and the luminance signal Y is FM modulated on the high frequency side, and the carrier color signal CP is frequency modulated on the low frequency side. At the same time, the phase of the carrier color signal is controlled as a countermeasure against the a-stoke as explained in FIG. This phase control of the carrier color signal is actually performed by controlling the phase of a carrier for frequency conversion of the carrier color signal. Then, a composite signal of the FM-modulated luminance signal and the frequency-converted and phase-controlled carrier color signal is sent to the head 5A through the recording side contact of the changeover switch q.
5B and recorded. Heads 5A, 5B; d
As mentioned above, the azimuth angles are different from each other 1,
On the other hand, the playback output of heads 5A, 3;B is controlled by selector switch q.
It is supplied to the regeneration processing circuit B through the regeneration side contact of the .

The reproduction processing circuit 6 corresponds to the reproduction system of a low-frequency conversion type recording and reproduction device for PAL color video signals, and is connected to the head 5A.
, 5B, the FM-modulated luminance signal and the frequency-converted and phase-controlled carrier color signal are separated, the separated luminance signal is FM demodulated, and the separated carrier color signal and the original frequency are separated. The phase of the carrier color signal is controlled in accordance with the control in the recording processing circuit wI3 to restore the state before recording, and the carrier color signal is passed through a comb-shaped filter for removing crosstalk components. taken out through. Note that the phase control of the carrier color signal during this reproduction is actually performed by controlling the phase of the carrier for frequency conversion of the carrier color signal. thus,
The output of the reproduction processing circuit B is the same luminance signal Y and carrier color signal CP as the long sword of the recording processing circuit 3, that is, a PAL color video signal 5. The color video signal is supplied to a reproduction conversion circuit 7 and converted into a SECAM color video signal. That is, in the reproduction conversion circuit 7, the carrier color signal Cp is converted into the carrier color signal C8O of the SECAM color video signal, and this carrier color signal C8o and the luminance signal Y
A composite signal of is extracted at the output.

The reproduced SECAM color video signal output from the reproduction conversion circuit 7 is high-frequency modulated by a high-frequency modulation circuit 9S as required, and is given to the SECAM receiver tO8.
The reproduced image can be viewed on the SECAM receiver LOS.

Note that the luminance signal Y and carrier color signal CP obtained from the reproduction processing circuit 6 are synthesized by a synthesizer g, and the synthesized PA
The L color video signal is sent to the high frequency modulation circuit 9P as required.
If the signal is high-frequency modulated and applied to the PAL receiver 10p, the reproduced image can also be viewed on the PAL receiver 10p.

The above example is a case where a SECAM color video signal is replaced with a PAL color video signal and recorded.
Instead of a color video signal, the signal may be converted into a similar signal and recorded as described later. However, in this case, since the signal to be reproduced is similar to the PAL color video signal, the PAL receiver toPk as in the example in FIG.
It is not possible to connect directly and view the playback images.

Figure 2 shows the recording conversion circuit 2 -1] and the S to be recorded.
1, when an ECAM color video signal is converted to a PAL color video signal, the SECA applied to the input terminal l
When the M color video signal is supplied to a low-pass filter /1 and a luminance signal Y is extracted, it is supplied to a Tomony-Herr type band-pass filter 72 and a carrier color signal C8 is extracted. The carrier color signal C8 is a signal in which FM-modulated signals of blue and red color difference signals continue alternately for each line.

FIG. 10 shows the luminance signal Y, the carrier color signal C8, and the color signals obtained in each section, which will be described later, for each line.

Usually, blue color difference signal or its modulation; i*signal 1dB-
Y, -(B-Y), and the red color difference signal or its modulated signal is expressed as R-Y, -(R-Y),
In Fig. 10 and Fig. 1/Fig. 12 described later, B-Y
, -(B-Y), RY, and -(RY) are respectively represented by B, -B, R, and -R. Note that although the color signal C5ol' is delayed by the carrier color signal Csk/line as described later, the number of the suffix attached to the signal on each line is l less than that of the luminance signal Y. indicates that the content originally corresponds to the luminance signal l lines before.

The luminance signal Y is supplied to the synchronization separation circuit 31, a horizontal synchronization signal is taken out, and a flip is performed using this horizontal synchronization signal. The flop 32 is triggered to obtain a signal from the clip flop 32 that inverts every l line. 7 Also, the carrier color signal Cs is supplied to the gate circuit 33, the horizontal synchronization signal from the synchronization separation circuit 3/ is supplied to the gate pulse generation circuit 3da, and a gate pulse of the unmodulated carrier is obtained,
This gate pulse is supplied to the gate circuit 33, and from the gate circuit 33, unmodulated carriers are extracted from the carrier color signal Cs whose frequencies alternately vary from line to line. and,
The frequency of this unmodulated carrier is discriminated by a frequency discrimination circuit 3, and a flip-flop 32 is controlled by the discrimination output, and the signal obtained from the slip-flop 32 is FM modulated by a color difference signal in which the carrier color signal Cs is blue. The carrier color signal C8 is regulated to a negative state on the signal line where the red color difference signal is FM modulated, and the carrier color signal C8 is regulated to another state on the FM modulated signal line of the red color difference signal. The signal is supplied and demodulated once. In this example, the color demodulation circuit 20 (ri) performs FM demodulation on all the carrier color signals simultaneously to obtain demodulated outputs of blue and red color difference signals for each line at the same time. In other words, the carrier color signal Cs is delayed by 1 line in the delay line 21, and the carrier color signal Cs and the carrier color signal CsD delayed by 1 line are supplied to the switch 22.
However, due to the signal obtained from the flip p-tube 32, the carrier color signal Cs is FM-modulated with a blue color difference signal, and the state shown in the figure is obtained, and the carrier color signal C3 is FM-modulated with a red color difference signal. For the signal lines, the state is reversed to that shown in the figure, and the state is alternately switched line by line, and as shown in FIG. The FM modulated signal FB of the color difference signal is supplied from the other output terminal to the FM demodulator 23R, and the FM modulated signal FR of the red color difference signal is supplied to each line from the FM demodulator 23f3 to the de-emphasis circuit 2G. The demodulated output of the blue color difference signal is output from the FM demodulator 2JR to the de-emphasis circuit 2pR on each line through 'll1.
The demodulated outputs of the red color difference signals are obtained on each line through the color demodulation circuit 2θ.Then, the demodulated outputs of the blue and red color difference signals obtained simultaneously for each line are output from the balanced modulator 〆vB and tpR and are AM modulated using separate modulation axes perpendicular to each other. In this example, the phase of the modulation axis for the red color difference signal is inverted every l lines. That is, a carrier of <z, 1 MHz, which is the color subcarrier frequency of the PAL color video signal, is obtained from the oscillator G'/, and this carrier is supplied to the balanced modulator/GfB as a carrier of the B-Y axis, and the blue The demodulated output of the color difference signal is subjected to AM modulation on the BY axis. On the other hand, the carrier on the B-Y axis to/from the oscillator is delayed by 900 by phase shifter Ko2 and becomes the carrier on the -(R-Y) axis as shown in FIG. The phase of the y) axis carrier is inverted by Innovator 3 to become the R-Y axis carrier, and this R-Y! F
The carrier of ll and the carrier of the -(R-Y) axis are supplied to the switch μμ, and the signal obtained from the flip-flop 32 causes the carrier color signal Cs to be switched to the switch in the line of the FM modulated signal of the blue color difference signal. %' is switched to the state shown in the figure, and the R-Y axis carrier is balanced modulator/Gl.
The demodulated output of the red color difference signal becomes R-
In the signal line where the Y axis is AM modulated and the carrier color signal Cs is an FM modulated red color difference signal, the switch UU is switched to the opposite state to the state shown in the figure, and the carrier on the -(R-Y) axis is By being supplied to the balanced modulator lsuR, the demodulated output of the red color difference signal is AM-modulated on the -(RY) axis. The phase of carrier XR obtained from switch +4 & is 10th
As shown in the figure, the upward direction is the R-Y axis, and the downward direction is -(R-
Y) axes are shown respectively.

AM-modulated signals AB and AR of the blue and red color difference signals obtained simultaneously from the balanced modulator/LIB and 1LIR for each line in this way are combined in the combiner 15, and the AM modulated signals of the blue and red color difference signals are Modulated signals AB and A
A signal in which R is combined line by line is supplied to a switch lB for adding a burst signal.

The switch 16 is switched to the state shown in the figure during periods other than the burst signal period by the gate pulse obtained from the gate pulse generation circuit 3, and is switched to the state opposite to the state shown in the figure during the burst signal period. , and in this case, the carrier from the phase shifter 12 is ψS0 in the phase shifter qL.
The carrier is delayed and made into a carrier with a phase delayed by Ll5'' with respect to the -(R-Y) axis, and this carrier is further shifted by 9 by the phase shifter ψ7.
The carrier is delayed by 0' and is made into a carrier whose phase is advanced by Ll 0 with respect to the RY axis, and the carrier whose phase is advanced by s0 with respect to this RY axis and the -(RY) axis , a carrier with a phase delayed by 5-' is supplied to the switch vg, and the signal obtained from the flip-flip 32 causes the transmission signal Cs to be FM modulated in the blue color difference signal line, and the switch vg is is switched to the state of R-
The carrier whose phase is GI0 advanced with respect to the Y axis is the switch l.
In the line where the carrier color signal Cs is FM modulated as a red color difference signal, the switch yg is switched to the opposite state to that shown in the figure, and the l is A carrier whose phase is delayed by 0 is supplied to the switch /l. Therefore, by swing ft4, the AM-modulated signals AB and AR of the blue and red color difference signals are combined line by line, and a burst signal whose phase is advanced by 0 with respect to the R-Y axis is generated. A burst signal having a phase delayed by V5 degrees with respect to the -(R-Y) axis is added alternately to each line in the manner shown in FIG. is taken out, and the carrier color signal C of the PAL color video signal is output to the output terminal 17.
p is obtained. That is, the SECAM color video signal to be recorded is converted into a PAL color video signal.

FIG. 5 shows a PAL signal that is reproduced by the -11 of the reproduction conversion circuit 7 when the recording conversion circuit 2 is configured as shown in FIG.
A luminance signal Y of a color video signal is applied to an input terminal l, and a carrier color signal CP is applied to an input terminal s2. This P
The AL color video signal is the same as that obtained at the output of the recording conversion circuit shown in FIG.

The luminance signal Y is supplied to the synchronization separation circuit g/ to extract the horizontal synchronization signal, and this water'''-Y synchronization signal triggers the flip-70 tube g2, which inverts every l line from the flip-flop g2. In addition, the carrier color signal cp is supplied to the burst gate circuit 3, and the horizontal synchronization signal from the sync separation circuit gl is supplied to the gate pulse generation circuit ge to generate a burst 1 pulse. Kate Halska Hearst Skate Episode 11.3
G,? tc is supplied from circuit g3 and continues alternately for each of the above-mentioned lines in the carrier color signal cp.
This burst signal 1 and B- are taken out.
- is supplied to the oscillator 91, e.g. by injection zero, from the oscillator 9/ to the -(B-Y) axis at v, v3 MHz and midway between the phases of the burst signals B- and B- as shown in FIG. The carrier is obtained, and this −(B
- The phase of the carrier on the η axis is inverted by the inverter 192, and B
This B-Y axis carrier is delayed by 900 by a phase shifter qe to become a -(R-Y) axis carrier.

Then, the burst signal liver and B- from the burst gate circuit g3 are phase-detected by the carrier of this - (RY) axis in the phase detection circuit g, and the detected output is used as a flip signal.
The flop g2 is controlled so that the signal obtained from the clip flop g2 is a burst signal B10 line corresponding to the line of the signal obtained by converting the carrier color signal C8 on the recording side to the blue color difference signal F'M)Rm. - state, Ii
The color of the color signal CsI! The burst signal line corresponding to the FM modulated signal line 'j+-5 is regulated to another state, and the carrier color signal Cp is supplied to the color demodulation circuit 70 and once demodulated. The color demodulation circuit 70 performs AM demodulation of the carrier color signal Cp using a demodulation axis corresponding to the modulation axis of AM modulation in the recording conversion circuit 2 to obtain demodulated outputs of blue and red color difference signals alternately for each line. It looks like this.

That is, the carrier color signal CP is synchronously detected by the carrier on the BY axis from the inverter 92 in the synchronous detection circuit 7/13, and the demodulated output DB of the blue color difference signal is obtained for each line, which is sent to the low-pass filter 72B (H On the other hand, =(B-Y
)m carrier is delayed by qo0 by the phase shifter 93 and R-Y
This R-Y axis carrier and the −(R-Y) axis carrier from the phase shifter 9V mentioned above are supplied to the switch 9, and the signal obtained from the flip-flop g2 causes recording. At the burst signal main line where the carrier color signal Cs on the side corresponds to the FM modulated signal line of the blue color difference signal, the switch 9S is switched to the state shown in the figure, and the carrier on the R-Y axis is taken out and the carrier is transferred. Color signal C
In the line of the burst signal B-, which corresponds to the line of the FM modulated signal of the red color difference signal, the switch 9S is switched to the opposite state to that shown in the figure, and the carrier on the -(R-Y) axis is taken out. Then, the carrier color signal CP is phase-inverted in the synchronous detection circuit 7/R to the R-Y axis and the -(R-Y) axis for every l line from this switch pig.
A demodulated output DR of the red color difference signal is obtained from each line through synchronous detection by R, and is supplied to the switch 3 through the core low-pass filter 2R. Then, by the signal obtained from the flip hoop gco, the switch 73 is set to the state shown in the figure when the carrier color signal C8 on the recording side is on the line of the burst signal B+ corresponding to the line of the FM modulated signal of the blue color difference signal. The demodulated output of the blue color difference signal is taken out, and the carrier color signal C8 is switched to the F of the red color difference signal.
In the burst signal line corresponding to the M-modulated signal line, the switch 73 is switched to the opposite state to that shown in the figure, and the demodulated output of the red color difference signal is taken out. The signal DBR obtained from this switch 73, that is, the signal DBR obtained from the color demodulation circuit 70 is of the form shown in FIG.

Next, a signal DBR in which the demodulated outputs of the blue and red color difference signals continue alternately line by line is sent to the SECAM encoder 5.
3, a signal indicating whether it is the demodulated output of the blue color difference signal or the demodulated output of the red color difference signal from the flip-flop g2, the gate pulse from the gate pulse generation circuit re, and the synchronization separation circuit. The synchronizing signal from g/ is supplied to the SECAM encoder 3, and the demodulated outputs of the blue and red color difference signals are converted into FM using different frequencies.
At the same time, an unmodulated carrier is added to the FM modulated signal to obtain a carrier color signal C8O of the SECAM color video signal. In this case, as is clear from FIG. 1O, the temporal relationship of this carrier color signal Cso with respect to the luminance signal Y is the same as that of the carrier color signal C8 on the recording side, that is, the time relationship in line units with respect to the luminance signal Y is There is no deviation. When the switch 73 is switched in the opposite manner as described above, the signal obtained from the color demodulation circuit 70 becomes the signal D in FIG.
As shown by BR', a time lag occurs by l line with respect to the luminance signal Y.

Then, the luminance signal Y and this carrier color signal Cso are synthesized by the synthesizer tag, and S is output as a reproduction output at the output terminal 5.
FIG. 6 shows another example of the reproduction conversion circuit 7 when the recording conversion circuit 2 is configured as shown in FIG.

The reason why the phase of the modulation axis for the red color difference signal in the carrier color signal of the PAL color video signal is inverted every line is that the color demodulation circuit of the receiver has a so-called standard system configuration, and this results in phase distortion. This is because it will be corrected. In consideration of this point, the example shown in FIG. 6 is a case where the color demodulation circuit 70 has a standard configuration so that the phase distortion is corrected.

That is, at point 0 in FIG. 6, the carrier color signal CP is already delayed by 1 line, and the carrier color signal CP and the carrier color signal CPD delayed by 1 line are sent to the adder 7 and the subtracter 7. A sum signal Cpp and a difference signal CPM of both are obtained, and the sum signal CPP is sent to the synchronous detection circuit? /13 is synchronously detected by the carrier on the B-Y axis, and the difference signal CPM is synchronized by the carrier YR whose phase is inverted to the RY-axis and the -(RY) axis every l line in the synchronous detection circuit 7/R. Detected. ,
The rest is the same as the column in FIG. S. FIG. 1/FIG. This is a synchronous detection circuit that shows the luminance signal Y and the color signals obtained in each part line by line.

The component represented by α in the demodulated output DR of the blue color difference signal from the 77B is the AM modulated component of the red color difference signal in the sum signal CPP, which is demodulated on the B-Y axis. β in the demodulated output DR of the red color difference signal from 7/R
The component represented by is A of the blue color difference signal in the difference signal CPM.
The M-modulated component is demodulated along the RY axis.

The switch 73 of the color demodulation circuit 70 is switched in exactly the same way as in the case of FIG.
The demodulated component of the color difference signal of another color is not mixed in the signal DBH obtained from the SE signal to be recorded.
This is a case where a CAM color video signal is converted into a signal similar to a PAL video signal (1).The example in FIG. 1 is a case where a CAM color video signal is converted into a complete PAL color video signal.
Since it is returned to the SECAM color video signal in the reproduction conversion circuit 7, the carrier color signal of the color video signal obtained from the recording conversion circuit 2 is a combination of AM-modulated blue and red color difference signals line by line. It doesn't have to be something like
The example in Figure 7, which can be continued alternately line by line, is
In view of this point, when the carrier color signal is converted into a color video signal in which AM-modulated signals of blue and red color difference signals continue alternately line by line, it is considered that the signal is similar to the PAL color video signal. In this example as well, just as in the case of FIG. 1, a signal is obtained from the flip-flop 32 that is inverted every l line, and this signal also indicates that the carrier color signal C8 is a blue color difference signal. The carrier color signal C8 is regulated to a negative state in the FM modulated signal line, and to another state in the FM modulated signal line where the carrier color signal C8 is a red color difference signal.

In this example, the color demodulation circuit θ performs FM demodulation on the carrier color signals without synchronizing them to recover blue and red color difference signals.
The modulation output is obtained alternately for each line. That is, the carrier color signal C8 is supplied to the switch 25, and the switch 2S changes the carrier color signal C8 to the state shown in the figure in the FM modulated signal line of the blue color difference signal by the signal obtained from the three flip-flops. , the carrier color signal Cs is alternately switched every l line to the opposite state to the state shown in the figure in the FM modulated signal line of the red color difference signal, and the FM demodulator 23B is switched from the negative output terminal of the switch 2S to the FM demodulator 23B. An FM modulated signal of the blue color difference signal is supplied to every other line, and an FM modulated signal of the red color difference signal is supplied to the FM demodulator 23R from another output terminal to the FM demodulator 23R every other line.
Demodulator 23f3 to deenophasis circuit 2tlB'r
The demodulated output of the blue color difference signal every l line through the FM
Demodulated outputs of red color difference signals are obtained from the demodulator 2JR through the de-emphasis circuit 2%R'i every other l line, and both are taken out as a common output.

Next, the demodulated outputs of the blue and red color difference signals obtained alternately for each line from this color demodulation circuit 20 are supplied to a common balanced modulator/F, and the signal obtained from the flip-flop 32 is used to output the FM demodulator 2. ] In the line where the demodulated output of the blue color difference signal is obtained from 3, the switch cover is changed to the state shown in the figure, and the carrier from the oscillator &/
The demodulated output of the blue color difference signal is supplied to the balanced modulator/K as a carrier of the axis, and the demodulated output of the blue color difference signal is AM-modulated on the B-Y axis. ? In the line where the demodulated output of the red color difference signal is obtained from R, the switch 5 is switched to the opposite state to that shown in the figure, and the R-Y axis carrier from the inverter 13 is supplied to the balanced modulator/U. Then, the demodulated output of the red color difference signal is AM modulated on the R-Y axis, and as shown in Figure 1, the AM modulated signals of the blue and red color difference signals are transmitted line by line from the balanced modulator / A signal ABR is obtained which follows alternately.

This signal ABR is then supplied to a switch 16 for adding a burst signal.

In this case, in a line where the carrier color signal C8 is an FM modulated signal of a blue color difference signal and the signal ABR is an AM modulated signal of a blue color difference signal, the -(R-Y) axis from the phase shifter v6 A carrier with a phase delayed by 0 geta is supplied to the switch 16, that is, the above-mentioned burst signal B- is added, the carrier color signal C8 is an FM modulated signal of the red color difference signal, and the signal ABR is the red color difference signal. In the AM modulated signal line of the signal, a carrier whose phase is <150 ahead with respect to the RY axis from the phase shifter 7 is supplied to the switch 16, that is, the above-mentioned burst signal core is added. .

In this way, the luminance signal Y is taken out at the output terminal 13, and the carrier color signal CP' similar to the carrier color signal of the PAL color video signal is obtained at the output terminal 17. That is, the SECAM color video signal to be recorded is converted into a signal similar to a PAL color video signal.

FIG. 3 shows the reproduced PAL at -[+1 of the reproduction conversion circuit 7 when the recording conversion circuit 2 is configured as shown in FIG.
A luminance signal Y, which is a signal similar to a color video signal, is applied to the input terminal 51, and a carrier color signal CP' is applied to the input terminal 2. A signal that is inverted every l line is obtained, and this signal is in a - state in the line of the burst signal B-, which corresponds to the line of the FM-modulated signal of the blue color difference signal, in which the conveyed color signal C8 on the recording side is in the - state. In addition, the carrier color signal C8 is regulated to another state in the burst signal line corresponding to the FM modulated signal line of the red color difference signal.
, and the carrier color signal CP' is supplied to the color demodulation circuit 70 and once demodulated. That is, the carrier color signal CP' is supplied to the switch 77, and the switch 77 causes the carrier color signal CP' to become a burst signal with an AM modulated signal of the blue color difference signal by the signal obtained from the flip 70 knob g2. The line is switched to the state shown in the figure, and the carrier color signal CP' is an AM-modulated red color difference signal, and the burst signal B+ line is switched to the state opposite to the state shown in the figure. The AM-modulated signal of the blue color difference signal is sent from the - output terminal of block 7 to the synchronous detection circuit tf3 every l line, and from the other output terminal to the synchronous detection circuit 7/R.
AM-modulated red color difference signals are supplied to every other line, and demodulated outputs of blue color difference signals are supplied to every other line from the synchronous detection circuit 77B through the low-pass filter 72Bf. /R to low pass filter tough 2Rf
The demodulated output of the red color difference signal every other l line is
and both are taken out to a common output. Na,
As in the case of FIG.
The signal is supplied to an encoder 53 to obtain a carrier color signal Cso of the SECAM color video signal. In this case as well, the first
As is clear from FIG. 2, this carrier color signal C8O has no line-by-line time lag with respect to the luminance signal Y. According to the present invention, the low-frequency conversion for existing PAL color video signals By simply providing a conversion circuit in the recording system and reproducing thread of a recording/reproducing device, SECAM color video signals can be easily recorded in high density.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams for explaining the entire high-density recording method, Figure 3 is a system diagram schematically showing the overall configuration of an example of the device of the present invention, and Figure 9 is a recording conversion circuit. FIG. 6 is a system diagram of an example of the conversion circuit for reproduction, and FIG. 7 is a system diagram of another example of the conversion circuit for recording.
FIG. 3 is a system diagram of one line of the corresponding reproduction conversion circuit, and FIGS. 9 to 12 are diagrams for explaining the operation of the recording conversion circuit and reproduction conversion circuit, respectively. be. In the figure, C is a recording conversion circuit, // is a low-pass filter that separates the luminance signal, L is a bad-pass filter that separates the carrier color signal, 2θU-t color demodulation circuit, /F
13, /lIR and /G' are its balanced modulators, /A
is a switch for adding the burst signal, G(/
3 is its oscillator, 3 is its recording processing circuit, O is its reproduction processing circuit, 7 is its reproduction conversion circuit, 70 is its color demodulation circuit, 9
t is its oscillator and SECAM encoder.

Claims (1)

[Claims] The recording system is provided with a recording conversion circuit and a recording processing circuit, and the reproduction system is provided with a reproduction processing circuit and a reproduction conversion circuit, and the recording conversion circuit converts the input SECAM color video signal into a luminance signal. Color demodulation includes a filter that separates the carrier color signal, and FM demodulation of the carrier color signal of the separated SECAM color video signal with or without simultaneous FM demodulation to obtain demodulated outputs of two color difference signals simultaneously or alternately for each line. circuit, and the demodulated outputs of the two color difference signals obtained simultaneously or alternately for each line are A-IVI modulated using separate modulation axes perpendicular to each other to produce AM modulated signals of the two color difference signals for each line. A color modulation circuit that synthesizes or alternately obtains the AM-modulated signals of these two color difference signals line by line, or a carrier color signal of the separated SECAM color video signal into a signal that is synthesized line by line or continues alternately. A burst signal whose phase is alternately changed is added to each l line depending on whether the line is an FM modulated signal line of the color difference signal or an FM modulated signal line of another color difference signal. It consists of a burst signal addition circuit that obtains a carrier color signal converted for recording, and in the recording processing circuit, the luminance signal separated by the recording conversion circuit is FM modulated on the high frequency side, and The carrier color signal converted for recording obtained from the conversion circuit is frequency-converted to the lower frequency side, and the phase of the carrier color signal is controlled for crosstalk countermeasures, and the above-mentioned FM-modulated luminance signal and the above-mentioned frequency are A composite signal of the converted and phase-controlled carrier color signal is supplied to the head, and in the reproduction processing circuit, the FM-modulated luminance signal and the frequency-converted and phase-controlled carrier color are output from the head. The signal is separated, the separated luminance signal is FM demodulated, the separated carrier color signal is frequency-converted to the original frequency, and the phase of the carrier color signal is controlled in accordance with the control in the recording processing circuit. At the same time, the carrier electric signal is extracted through a comb-shaped filter for removing crosstalk components, and the reproduction conversion circuit converts the carrier signal obtained from the reproduction processing circuit and the recording signal obtained from the recording conversion circuit. A carrier color signal corresponding to the converted carrier color signal is AM demodulated using a demodulation axis corresponding to the modulation axis of AM modulation in the recording conversion circuit to obtain demodulated outputs of two color difference signals alternately for each line. A color demodulation circuit performs FM modulation using different frequencies on the demodulated output total pressure of the two color difference signals obtained alternately for each line, and adds an unmodulated carrier to the FM modulated signal to produce a SECAM color image. A SECAM color video signal recording and reproducing device comprising a SECAM encoder for obtaining a color signal carrying a hoe signal.