JPH05207512A - System for recording color video signal - Google Patents

Abstract

PURPOSE:To attain recording and reproduction of a broad band carrier chrominance signal by superimposing a subcarrier broad band one-side band component onto a low frequency conversion chrominance carrier signal through frequency interleave and recording the result, and regenerating the resulting signal. CONSTITUTION:The low frequency component output signal CL of a BPF 2 is fed to an adder circuit 4 through a subtractor 6, a frequency converter 7, and a delay circuit 3 taking the delay time difference of a BPF 9 into account, in which the signal is added to a high frequency component signal CH subjected to frequency conversion from the BPF 9. An addition output signal from the circuit 4 is fed to a frequency conversion circuit 10 for low frequency. The signals CH, CL are synthesized in the circuit 10 in frequency interleave and a chrominance carrier signal subjected to the low frequency conversion so as to attain frequency interleave between adjacent tracks is obtained and the signal is fed to an adder circuit 18 through an LPF 17. Furthermore, the luminance signal is frequency-modulated, a frequency modulated luminance signal YFM is fed to the circuit 18, both are added and recorded on a magnetic tape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a household VTR, for example.
Relates to a color video signal recording method that enables recording of color signals in a wider band.

[0002]

2. Description of the Related Art Household VTR such as so-called 8 mm VTR
In the so-called low frequency conversion color system, the luminance signal is frequency-modulated, and the carrier color signal is frequency-converted to the low frequency side of the FM-modulated luminance signal, and both are combined and recorded.

In the current low frequency conversion color system VTR,
The carrier frequency for low frequency conversion is defined by the standard,
Thereby, the band of the color signal is determined. For example,
The current domestic VTR has a frequency of 500 kHz.

[0004]

By the way, recently, a wideband color video signal has been obtained from a video camera or other video source, and it is desired to record the wideband color video signal. .. However, as described above, in the VTR of the low frequency conversion color system, once the low frequency conversion carrier frequency of the carrier color signal is determined by the standard, the band of the color signal is determined thereby, and the color image of the wide band is obtained. It is difficult to record the signal.

In view of the above points, the present invention is a conventional VT.
An object of the present invention is to provide a color video signal recording method capable of recording color signals in a wide band while achieving compatibility with R.

[0006]

In order to solve the above problems, a color video signal recording method according to the present invention is such that the luminance signal of the color video signal is frequency-modulated and the carrier color signal is the frequency-modulated luminance. When converting the frequency to the low frequency side of the signal and synthesizing both, and recording the synthesized signal on a recording medium, the wideband carrier color signal is divided into a high frequency component and a low frequency component, and the high frequency component and the low frequency component are separated. A frequency component is frequency-converted to the low-frequency side and synthesized as a signal of substantially the same frequency band and recorded, and the high-frequency component and the low-frequency component are in a frequency interleaved relationship with each other. At the same time, between the adjacent tracks, the high frequency component and the low frequency component are recorded so as to be in a frequency interleaved relationship with each other.

[0007]

In the color video signal recording system of the present invention having the above-described structure, the carrier color signal is divided into a high frequency component and a low frequency component, and the signals are substantially in the same frequency band while being frequency interleaved with each other. Is converted to a low frequency band, and is synthesized and recorded. Moreover, between the adjacent tracks, the high-frequency component and the low-frequency component are recorded so as to have a frequency interleaved relationship with each other.

The high frequency component of the carrier color signal is a conventional home V
According to the present invention, the carrier color signal is recorded in a wide band by recording the high frequency component which is not recorded in TR.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color video signal recording system according to the present invention will be described below with reference to the drawings. Figure 1
FIG. 2 is a block diagram of an embodiment of a main part of a recording apparatus to which the color video signal recording system according to the present invention is applied, and FIG. 2 shows frequency allocation of each signal for its explanation.

In FIG. 1, reference numeral 1 is an input terminal for a color video signal, and a wideband NTSC carrier color signal is input through this input terminal. This wideband NTSC carrier color signal has a single sideband wideband I-axis signal and a narrowband Q signal (see FIG. 2A). In this case, the carrier color signal has an I signal frequency band of 1.5 MHz as shown in FIG. 2A.
The Q signal overlaps a portion of the I signal band having a width of 500 kHz.

The broadband carrier color signal from the input terminal 1 is supplied to the bandpass filter 2 having a width of about ± 500 kHz, and the I signal and the Q signal are overlapped at 500 kHz.
A signal CL (see FIG. 2B) consisting of I and Q signals of width is obtained from this.

The broadband carrier color signal from the input terminal 1 is also supplied to the subtractor 6 through the delay circuit 5 in consideration of the delay time in the bandpass filter 2, and the signal CL from the bandpass filter 2 is also supplied. Is supplied to the subtractor 6. In the subtractor 6, the output signal CL of the bandpass filter 2 is subtracted from the wide band input carrier color signal, and as a result, the high frequency component CH (see FIG. 2C) of the input carrier color signal is subtracted from the subtractor 6. can get.

The output signal CH of the subtractor is supplied to the frequency conversion circuit 7, and the center frequency is {fsc (3.58MH) by the frequency conversion carrier S1 through the terminal 8.
z) + 1 / fh (fh is a horizontal frequency)} (see FIG. 2D). By this frequency conversion, the signal CL and the signal CH are in the same frequency band and are in a state of being interleaved with each other by a frequency of 1/2 fh.

In this case, the frequency of the frequency converting carrier S1 is (nfh + 1 / 2fh) as shown in FIG. 2C.
It is said that. The frequency of the frequency conversion carrier S1 is
When the difference between the center frequencies of the signal CL and the signal CH is about 1 MHz, n = 63 is selected, for example.

A signal CH whose center frequency from the frequency conversion circuit 7 has been frequency-converted to the above (fsc + 1 / 2fh).
Is supplied to the adder circuit 4 through the bandpass filter 9. The output signal CL of the bandpass filter 2 is
The signal is supplied to the adder circuit 4 through the delay circuit 3 in consideration of the delay time difference of the subtractor 6, the frequency converter 7, and the bandpass filter 9, and is added to the frequency-converted signal CH from the bandpass filter 9. In this case, as described above, the signal CL supplied to the adder circuit 4 and the frequency-converted signal CH from the bandpass filter 9 are in a state of frequency interleaving.

The addition output signal from the addition circuit 4 is supplied to the frequency conversion circuit 10 for low frequency conversion. Further, the frequency conversion circuit 10 is supplied with a frequency conversion signal from the switch circuit 15. This frequency conversion signal is formed as follows.

That is, the original subcarrier frequency fsc and the target low-frequency conversion carrier frequency fc are used.
(For example, in case of 8 mm VTR, fc = (47 + 1 /
4) Frequency (fsc + f) of sum with fh = 743 kHz
The continuous wave signal Scw of c) is supplied to one input end of the switch circuit 12 through the input terminal 11 and, after being 180 ° phase-inverted by the inverter 13, is supplied to the other input terminal of the switch circuit 12. It The switch circuit 12 is alternately switched between one input end and the other input end for each horizontal section by the signal SH of the frequency 1 / 2fh from the terminal 14.

The output signal of the switch circuit 12 is supplied to one input terminal of the switch circuit 15. Further, the signal Scw from the input end 11 is supplied to the other input end of the switch circuit 15. The switch circuit 15 is alternately switched to one input end and the other input end for each field by the signal SF of the frame frequency (30 Hz) from the terminal 16. Therefore, in a certain one-field section, the signal Scw is obtained from the switch circuit 15, and in the one-field section before and after that, the signal Scw and its inverted signal are alternately followed every horizontal section. The output signal of the circuit 12 is obtained.
Then, the output signal of the switch circuit 15 is supplied to the frequency conversion circuit 10 as a carrier signal for low frequency conversion.

Therefore, regarding a certain one-field period, the signal Scw of the frequency fsc + fc is always supplied to the frequency converter 10 as a frequency conversion signal during the one-field period, and the frequency converter 10 supplies the carrier frequency. A carrier color signal whose low frequency band has been converted to fc is obtained.

In the one field period before and after that,
For the frequency converter 10, the signal Scw and its inverted signal are alternately switched for each horizontal section (this is equivalent to (fsc + fc + 1 / 2f
The signal of the frequency h)) is supplied as a frequency conversion signal. Therefore, at this time, the carrier frequency from the frequency converter 10 is (fc + 1 / 2f).
The carrier color signal which has undergone the low frequency conversion to (h) is obtained.

As a result, the carrier color signals of the recording signals are in a state of frequency interleaving of 1/2 fh for each field (for each track).

In this way, from the frequency conversion circuit 10, as shown by C in FIG. 2E, the signal CH and the signal CL are combined in a state where they are frequency interleaved, and at the same time, they are frequency interleaved between adjacent tracks. Thus, the carrier color signal whose frequency is converted to the low frequency side is obtained, which is taken out through the low pass filter 17 and supplied to the adder circuit 18.

Further, the luminance signal from the input terminal 19 is
The FM modulation circuit 20 performs FM modulation, and the FM-modulated luminance signal YFM is supplied to the adding circuit 18, and both are added. Then, the addition output from the addition circuit 18 is supplied to the rotary magnetic head 22 via the recording amplifier 21 and recorded on the magnetic tape as an oblique track, one track per field.

In this case, the recording track pattern on the tape has a track width W shorter than the track pitch D, and a guard band is formed between adjacent tracks.

In the case of the 8 mm VTR,
As shown in FIG. 2E, the frequency-modulated luminance signal YFM
Is recorded on the high frequency side, and the low frequency conversion carrier color signal C is recorded on the low frequency side. In addition, these low-frequency conversion carrier color signals C
And an FM-modulated luminance signal YFM, a FM-modulated audio signal AFM is recorded in a band, and a tracking pilot signal PT is further recorded in a range lower than the carrier color signal C. Is.

Looking at each track of the recorded color video signal, the carrier color signal has a relationship in which the low-frequency component CL and the high-frequency component CH are frequency-interleaved with each other, as shown in FIG. 3A. Further, when viewed between adjacent recording tracks, as shown in FIGS. 3A and 3B, the low frequency component CL is
The two are frequency interleaved with each other, and the high frequency components CH are also frequency interleaved with each other. As described above, the reason why the guard band is provided between the tracks is that, in the case of one group of the signal CL and the signal CH between adjacent tracks, they overlap each other without having a frequency interleave relationship. This is because crosstalk from adjacent tracks cannot be removed from the signals CH and CL, so that crosstalk from adjacent tracks does not occur.

Whether the signal Scw is used as the frequency conversion carrier supplied to the frequency conversion circuit 10 or the output signal of the switch circuit 12 is used is synchronized with the pulse PG indicating the rotational phase of the rotary head drum, for example. The so-called track ID is determined by the conventional 8 mmV
Although recorded in TR as well, in the case of this example, the track ID is given to the signal CL.

Next, in the above example, the signal CH is changed to the signal C.
In a state where H and the signal CL are frequency-interleaved with each other, frequency conversion is performed so that the frequency band is substantially the same as that of the signal CL, the signal CH and the signal CL are combined, and the combined signal is mutually added between adjacent tracks. Although the low frequency conversion is performed so that frequency interleaving is performed, the signal CH
And the signal CL may be low-pass-converted so as to have the above relationship, and the low-pass-converted signals may be combined. An example in that case is shown in FIG.

That is, the signal CL from the bandpass filter 2 is supplied to the frequency conversion circuit 23, and the signal CH from the subtractor 6 is supplied to the frequency conversion circuit 24.
A frequency conversion carrier generation circuit for alternately generating the signal Scw and the signal equivalent to the signal Scw (the signal from the switch circuit 12) differing in frequency by 1/2 fh for each field. 25 and 26 are provided, and in the field period in which the signal Scw is generated from one generation circuit, the other generation circuit equivalently halves the above.
A signal having a frequency different by fh is generated.

Then, low frequency conversion is performed in the frequency conversion circuits 23 and 24 by the carrier signals from the frequency conversion carrier generation circuits 25 and 26. Then, the converted output is taken out through the low-pass filters 27 and 28, is supplied to the adding circuit 29, and is supplied to the adding circuit 18 with the FM luminance signal.

Next, an example of a reproduction system of the color video signal recorded by the recording system of the example of FIG. 1 will be described with reference to FIG.

That is, the reproduction high frequency signal from the reproduction rotary head 31 is supplied to the high pass filter 33 through the reproduction amplifier 32, and the FM luminance signal is obtained from this.
This is FM demodulated in the FM demodulation circuit 34, and the luminance signal Y is obtained.

The output signal of the reproduction amplifier 32 is also supplied to the low-pass filter 35, from which a low-frequency converted carrier color signal is obtained, which is supplied to the frequency conversion circuit 36.

On the other hand, the frequency fsc + fc from the input terminal 37
The continuous wave signal Scw is supplied to one input end of the switch circuit 38, and the inverter 39 outputs 180 °.
After being phase-inverted, it is supplied to the other input terminal of the switch circuit 38. This switch circuit 38 has an input terminal 40.
Through the signal SH having a frequency of 1/2 fh through, the input terminals are switched to the one input terminal and the other input terminal alternately for each horizontal section.

The output signal of the switch circuit 38 is supplied to one input end of the switch circuit 41, and the signal Scw from the input end 37 is supplied to the other input end of the switch circuit 41. Switch circuit 41
Are alternately switched to one and the other input ends for each field by the signal SF from the terminal 42. Then, the output signal of the switch circuit 41 is supplied to the wave number conversion circuit 36 as a frequency conversion signal.

In this case, the switch circuit 4 according to the signal SF
The switching state of 1 is defined by the track ID described above. Therefore, the frequency conversion circuit 36
From the carrier color signal component C returned to the original frequency band
L and CH are obtained and this is the bandpass filter 43.
Taken out through. The output signal of the bandpass filter 43 is supplied to the comb filter 44, and the signal CL and the signal CH are in a frequency interleaved relationship with each other.
From the comb filter 44.

The carrier color signal component CH from the comb filter 44 is supplied to the frequency conversion circuit 47, and the signal S1 from the terminal 48 (frequency is nfh + 1 / 2fh, n).
= 63), the signal is further converted into a signal in the original frequency band, and this is extracted through the low-pass filter 49. Then, the output signal of the low-pass filter 49 is
It is supplied to the adder circuit 46.

Further, the carrier color signal component CL from the comb filter 44 is supplied to the adder circuit 46 through the delay circuit 45 in consideration of the processing time in the frequency conversion circuit 47 and the low pass filter 49, and from the low pass filter 49. The original NTSC carrier color signal is obtained from this by combining with the signal CH.

The carrier color signal thus obtained is a carrier color signal in which the I-axis side band having a high eye color resolution is nearly doubled compared to the conventional carrier color signal. Therefore, carrier color signal information having a wider band than the conventional one can be obtained.

When the tape recorded by the above recording method is reproduced by the conventional VTR, the added carrier color signal component CH is removed by the crosstalk removing circuit using the comb filter. Therefore, only the carrier color signal component CL similar to the conventional one is reproduced, and compatibility is ensured.

Further, when the magnetic tape recorded by the conventional recording system is reproduced by the reproducing system corresponding to the present recording system, the comb filter 44 obtains an unnecessary crosstalk component. To deal with this, the identification signal is recorded on the tape recorded by the new recording method, and the component CL and the component CH are obtained by the comb filter 44 only when the identification signal is reproduced. Thus, when the identification signal is not obtained from the recording tape during reproduction, the component CH is removed from the comb filter 44 so that the tape recorded by the conventional device can be reproduced.

The above example is an example in which the carrier color signal is obtained from the signal Scw so as to obtain the frequency conversion signal for frequency interleaving between adjacent tracks, but only 1/2 fh for each field. Signals of different frequencies may be supplied to the frequency conversion circuit for frequency conversion.

Although the above example is the case of the so-called PI system, it goes without saying that the present invention can also be applied to the PS system (system in which the phase is changed by 90 for each horizontal section). Further, although the above example is the case of the 8 mm VTR, it goes without saying that the present invention can be applied to the case of the recording system of other home VTRs.

[0044]

As described above, according to the present invention, the wide band one sideband component of the subcarrier is frequency-interleaved and recorded on the low-frequency conversion carrier color signal so that it can be reproduced. ing. Therefore, as the reproduction signal, in addition to the conventional signal, a signal in which the band of one sideband is widened can be obtained, and recording / reproduction of a carrier color signal in a wide band can be performed.

When the tape recorded by the recording method of the present invention is reproduced by the conventional VTR, the band component of one side band added to the low frequency conversion carrier color signal can be removed by the crosstalk removing circuit. So the conventional VTR
It has the advantage that it can be played back and is compatible with.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a recording apparatus adopting a color video signal recording system according to the present invention.

FIG. 2 is a diagram showing frequency allocation for explaining the operation of the recording apparatus of FIG.

FIG. 3 is a diagram for explaining components of a low-frequency conversion carrier color signal.

FIG. 4 is a block diagram of a main part of another example of a recording apparatus for realizing the recording method according to the present invention.

FIG. 5 is a block diagram of an example of a reproduction system of a tape recorded by the recording device according to the present invention.

[Explanation of symbols]

 1 Input terminal for NTSC color video signal 2 Band pass filter 4 Adder circuit 6 Subtractor circuit 7 Frequency conversion circuit 8 Frequency conversion signal input terminal 10 Frequency conversion circuit for low frequency conversion 11 Frequency conversion for low frequency conversion Signal input terminal 18 Addition circuit with luminance signal 21 Recording amplifier

Claims (1)

[Claims] 1. A luminance signal of a color video signal is frequency-modulated, and a carrier color signal is frequency-converted to a lower frequency side of the frequency-modulated luminance signal to synthesize the two, and the synthesized signal is recorded on a recording medium. In the recording method of a color video signal to be recorded, a wideband carrier color signal is divided into a high frequency component and a low frequency component, and the high frequency component and the low frequency component are frequency-converted to the low frequency side to obtain substantially the same signal. What is synthesized and recorded as a signal of a frequency band, wherein the high-frequency component and the low-frequency component are in a relationship of frequency interleaving with each other, and between the adjacent tracks, the high-frequency component and the low-frequency component A recording method of a color video signal in which each of them is recorded so as to be in a frequency interleaved relationship with each other.