JPH10275304A - Method for recording and reproducing signal and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and easily improve the quality of a picture without expanding a signal processing circuit into a wide band. SOLUTION: At the time of recording, a luminance signal including a folding back component is recorded. The regenerated luminance signal YDM is sampled to generate a digital signal DYS (A) having the folding back component, and is sampled and band-limited to generate a signal DYM1 (B). Subsampling is set in an opposite phase between lines, and the next line is subsampled and band-limited to generate a signal DYM2 (C). The folding back component is canceled by making a changeover between the signals DYM1 and DYM2 to be selected to obtain a signal of a folding back component of both of the original signal component and the folding back component. This signal is added to a signal DT (D) obtained by subtracting the signal DYM1 from the signal DYS to generate an analog signal YR (E). The folding back component is removed from the signal YR by a filter to obtain an output signal YOUT (F) of a wide band.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a signal recording / reproducing method and a signal recording / reproducing apparatus. Specifically, during the recording operation, the analog luminance signal is converted into a digital luminance data signal, and sub-sampling having an offset between lines is performed, thereby converting the analog luminance signal of a predetermined band including the original signal component and the aliasing component. Generated and recorded on a recording medium, and at the time of reproduction operation, an analog luminance signal including an original signal component and a folded component is converted into a digital luminance data signal, and sub-sampling having an offset between lines is performed, thereby forming a folded component. Is obtained, and a broadband output luminance signal is obtained from a component obtained by folding the original signal component and the aliasing component, thereby widening the band of the luminance signal and improving image quality.

[0002]

2. Description of the Related Art In a conventional signal recording apparatus, for example, a video tape recorder, image quality has been improved by various methods. However, further improvement in image quality has been desired by, for example, increasing the screen size of a television receiver. As a method of improving the image quality, performance improvement of a magnetic tape and a magnetic head, reduction of noise, widening of a video signal, and the like are performed.

[0003]

By the way, as for the wide band of the video signal, for example, the resolution is improved by expanding the band of the luminance signal at the time of recording and reproduction and shifting the carrier frequency to a higher band to expand the recorded information. Is achieved.

In this case, not only the signal processing circuit for recording and the signal processing circuit for reproduction must have a wide band, but also
Since magnetic tapes, magnetic heads, and the like also need to have better performance, the image quality cannot be easily improved.

Accordingly, the present invention provides a signal recording / reproducing method and a signal recording / reproducing apparatus which can easily and easily improve the image quality without, for example, making the signal processing circuit wide.

[0006]

According to a signal recording / reproducing method according to the present invention, at the time of recording a luminance signal, an analog input luminance signal to be recorded is sampled at a predetermined frequency and converted into a digital luminance data signal. A composite luminance data signal including an original signal component and a folded component is obtained from the data signal, and the composite luminance data signal is converted into an analog luminance signal of a predetermined band and recorded, and the reproduced analog signal is reproduced when reproducing the luminance signal. The luminance signal is converted into a digital luminance data signal by sampling the luminance signal at a predetermined frequency, and the luminance data signal is processed to remove the aliasing component, and the composite luminance data includes the original signal component and the aliased component. A signal is obtained, and the composite luminance data signal is converted into an analog luminance signal and output.

A signal recording / reproducing apparatus according to the present invention comprises:
An analog input luminance signal to be recorded is sampled at a predetermined frequency and converted into a digital luminance data signal. From this luminance data signal, an analog recording luminance signal of a predetermined band including an original signal component and a folded component is obtained. Signal conversion means, signal recording means for recording the recording luminance signal obtained by the first signal conversion means on a recording medium, signal reproduction means for reproducing the recording medium to obtain an analog reproduction luminance signal,
The reproduced luminance signal obtained by the signal reproducing means was sampled at a predetermined frequency and converted into a digital luminance data signal. This luminance data signal was processed to remove the aliasing component, and the original signal component and the aliasing component were aliased. Second signal conversion means for obtaining an analog output luminance signal from the components.

In the present invention, at the time of a recording operation, an analog luminance signal is converted into a digital luminance data signal, and subsampling having an offset between lines is performed. An analog luminance signal including the original signal component and the aliasing component is generated based on the sub-sampling and is limited to a predetermined band, so that a circuit for performing processing such as FM modulation on the luminance signal is not widened.
An analog luminance signal including the original signal component and the aliasing component can be recorded.

At the time of reproducing operation, an analog luminance signal including an original signal component and a folded component obtained from a circuit for performing processing such as FM demodulation is converted into a digital luminance data signal and has an offset between lines. By performing the sub-sampling, the aliasing component is canceled, and it is possible to obtain a broadband output luminance signal from the original signal component and the aliasing component of the aliasing component having the high frequency component.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a signal recording / reproducing method and a signal recording / reproducing apparatus according to the present invention will be described, for example, when applied to a video tape recorder.

In a signal recording / reproducing apparatus according to the present invention, for example, a video tape recorder, an analog luminance signal Y shown in FIG. 1A is sampled at a predetermined sampling period T, and a digital luminance data signal DY indicated by ○ and □ marks.
Is converted to Further, sub-sampling for thinning out and selecting data from the luminance data signal DY is performed, and FIG.
As shown in the figure, data indicated by a circle is selected from the luminance data signal DY of the n-th line, and sub-sampling with an offset is performed on the next (n + 1) -th line to obtain the luminance data signal of the (n + 1) -th line. The data indicated by the squares is selected from DY. By converting the data signal obtained by the sub-sampling into an analog signal, a luminance signal subjected to band compression processing is obtained from the luminance signal Y and recorded on a magnetic tape. A sub-sampling demodulation process is performed on the obtained luminance signal to obtain a broadband luminance signal.

FIG. 2 shows the configuration of the signal recording / reproducing apparatus according to the present invention. In FIG. 2, the video input signal VIN
Is supplied to the Y / C separation unit 11. The Y / C separation unit 11 is constituted by, for example, a three-line comb filter, and separates the luminance signal YIN and the carrier chrominance signal CIN from the video input signal VIN. The luminance signal YIN separated by the Y / C separation unit 11 is supplied to a luminance signal processing unit 20, and the carrier chrominance signal CIN is supplied to a chrominance signal delay unit 30.

The luminance signal processing section 20 has the configuration shown in FIG. 3, and the luminance signal YIN is supplied to the signal switching circuit 201 of the luminance signal processing section 20. The signal switching circuit 201 is supplied with a luminance signal YDM described later. Further, the mode signal MD indicating that the video tape recorder is in the recording mode or the reproduction mode is supplied to the signal switching circuit 201. When the video tape recorder is in the recording mode, the brightness is determined based on the mode signal MD. The signal YIN is selected and supplied to the A / D conversion circuit 202. When the reproduction mode is set, the luminance signal YDM is selected and supplied to the A / D conversion circuit 202.
The mode signal MD will be described later.

In the A / D conversion circuit 202, the luminance signal selected by the signal switching circuit 201 is A / D converted to a digital luminance data signal DYS. This luminance data signal DYS is supplied to the data conversion circuit 203.

In the data conversion circuit 203, the luminance data signal DYS is converted into a two's complement luminance data signal and the two's complement luminance data signal is converted to facilitate arithmetic processing using the luminance data signal DYS. The data value is adjusted so as to be in a predetermined data range. The luminance data signal DYC obtained by converting the luminance data signal DYS by the data conversion circuit 203 is supplied to a 1H delay circuit 204, a subtractor 205, a delay circuit 207, and a latch circuit 220.

In the 1H delay circuit 204, the luminance data signal DYC is delayed by one horizontal scanning period and supplied to the subtractor 205 and the latch circuit 230. Therefore, the subtractor 20
In 5, the luminance data signal DYCn-1 delayed by one horizontal scanning period is subtracted from the luminance data signal DYCn. The subtraction data signal DS obtained by the subtracter 205 is supplied to the filter processing circuit 206.

The filter processing circuit 206 is configured using a band-pass filter or the like. The band is limited so that the subtracted data signal DS has a predetermined bandwidth centered on the frequency corresponding to the sub-sampling processing, and the data value is also reduced. 1 /
2 as the subtraction data signal DSF.
Supplied to

In the delay circuit 207, the supplied luminance data signal DYC is delayed by the time required for the filter processing in the filter processing circuit 206, and the subtracted data signal DSF
Is supplied to the subtractor 208 at the same timing as.

The subtracter 208 subtracts the subtraction data signal DSF from the luminance data signal DYC to obtain a luminance data signal DYP whose oblique band is limited.
Here, the band limiting operation of the oblique component will be described with reference to FIG.

FIG. 4A shows, for example, a black and white pattern in an oblique direction. For example, "1" is a white pattern and "-1" is a black pattern. Here, when sub-sampling the black and white pattern in the oblique direction, all “1” or all “−”
1 "pattern.

For this reason, as shown in FIG.
The difference component is obtained by subtracting the data value of the (n-1) line from the data value of the line. Further, when the difference component is band-limited around the sub-sampling frequency and the data value is halved and subtracted from the n-line data value, the influence on the frequency component different from the sub-sampling frequency is reduced. The band of the oblique component can be limited as a small number, and all "1" or all "-1"
Pattern can be prevented.

In this way, the subtraction data signal DS is processed by the filter processing circuit 206 to obtain the subtraction data signal DSF.
And subtracting it from the luminance data signal DYC,
It is possible to obtain the luminance data signal DYP in which the band of the oblique component has been limited. This luminance data signal DYP is supplied to the latch circuit 209.

The latch circuit 209 is supplied with a latch control signal ENA from a timing signal generation circuit 255 described later, and the luminance data signal DYP is latched based on the latch control signal ENA. This latch circuit 20
The data signal latched in 9 is supplied to the signal switching circuit 242 as a recording luminance data signal DYW which is a composite luminance data signal including an original signal component and a folded component.

The latch circuit 220 supplied with the luminance data signal DYC is supplied with a latch control signal ENA from the timing signal generation circuit 255, and the luminance data signal DYC is latched based on the latch control signal ENA. The data signal latched by the latch circuit 220 is supplied to the bandpass filter 221 and the delay circuit 222 as a luminance data signal DYL1.

In the bandpass filter 221, the luminance data signal DYL1 is band-limited so as to have a predetermined bandwidth centered on a frequency corresponding to the sub-sampling processing, and is supplied to the signal switching circuit 240 as a luminance data signal DYM1. This is supplied to the subtractor 223.

In the delay circuit 222, the supplied luminance data signal DYL1 is delayed by the time required for the filter processing in the bandpass filter 221, and the luminance data signal DYM1
Is supplied to the subtractor 223 at the same timing as.

In the subtractor 213, the luminance data signal DYL1
Is subtracted from the luminance data signal DYM1, and a subtraction data signal DT indicating the result of the subtraction is supplied to the adder 241.

The latch circuit 230 has a latch control signal E
A latch control signal ENB having a phase opposite to that of NA is supplied. Based on the latch control signal ENB, the luminance data signal DYC delayed by one horizontal scanning period and supplied from the 1H delay circuit 204 is latched. This latch circuit 23
The data signal latched at 0 is the luminance data signal DYL2
Is supplied to the bandpass filter 231.

In the bandpass filter 231, the bandpass filter 2
Similarly to 21, the luminance data signal DYL2 is band-limited so as to have a predetermined bandwidth around a frequency corresponding to the sub-sampling processing, and is supplied to the signal switching circuit 240 as the luminance data signal DYM2.

The signal switching circuit 240 is supplied with a latch control signal ENA. Based on the latch control signal ENA, one of the luminance data signal DYM1 and the luminance data signal DYM2 is selected and supplied to the adder 241. Is done.

The adder 241 adds the luminance data signal selected by the signal switching circuit 40 and the subtraction data signal DT supplied from the subtractor 223 to generate a composite signal including an original signal component and a component obtained by folding the folded component. A signal switching circuit 24 as a reproduced luminance data signal DYR which is a luminance data signal.
2 is supplied.

The mode signal MD is supplied to the signal switching circuit 242. When the video tape recorder is in the recording mode, the recording luminance data signal DYW is selected based on the mode signal MD and the data conversion circuit 243 is selected.
Supplied to When the reproduction mode is set, the reproduction luminance data signal DY is output based on the mode signal MD.
R is selected and supplied to the data conversion circuit 243.

In the data conversion circuit 243, the luminance data signal which has been complemented by twos in the data conversion circuit 203 is returned and supplied to the D / A conversion circuit 244.

In the D / A conversion circuit 244, the luminance data signal is converted into an analog luminance signal and supplied to the signal switching circuit 245. This signal switching circuit 245 is connected to the low-pass filter circuit 246 and the low-pass filter unit 61 shown in FIG. The mode signal MD is supplied to the signal switching circuit 245, and when in the recording mode, the signal switching circuit 24
The recording luminance data signal DYW selected in 2 is processed by the data conversion circuit 243 and the D / A conversion circuit 244 and supplied to the low-pass filter circuit 246 as an analog luminance signal YW.

In the low-pass filter circuit 246, the luminance signal Y
The band is limited so that W is a signal within a frequency band that can be recorded on the magnetic tape, and the luminance signal YX shown in FIG.
It is supplied to the M modulation processing section 41. In the reproduction mode, the reproduction luminance data signal DYR selected by the signal switching circuit 242 is supplied to the data conversion circuit 243 and the D / A
The signal is processed by the conversion circuit 244 and supplied to the low-pass filter unit 61 shown in FIG. 2 as an analog luminance signal YR.

The oscillation control circuit 251 has a synchronization signal SYN
C is supplied. The phase of a horizontal synchronization signal obtained from the synchronization signal SYNC is compared with the phase of a reference signal HD supplied from a counter circuit 254 to be described later, and an error signal ER indicating a phase error is supplied to the filter circuit 252. The voltage is supplied to the voltage-controlled oscillation circuit 253 via the power supply.

Here, the phase comparison is prohibited for a predetermined period during the vertical blanking period so as not to be affected by the skew generated in the video tape recorder. Further, a reset signal RT is supplied to the counter circuit 254 after a lapse of a predetermined period and several lines before the image is started, and the counter value of the counter circuit 254 is reset. At this time, the voltage control circuit 251 starts the phase comparison. The phase comparison is performed only for a predetermined period so that the oscillation control circuit 251 is not affected by the skew.

The oscillation frequency of the voltage-controlled oscillation circuit 253 is adjusted so that the phase of the horizontal synchronization signal obtained from the synchronization signal SYNC supplied to the oscillation control circuit 251 matches the phase of the reference signal HD supplied from the counter circuit 254. Under the control, the clock signal CLK is generated. This clock signal requires the clock signal CLK of the oscillation control circuit 251, the counter circuit 254, and the luminance signal processing unit 20.
/ D conversion circuit 202 and the like.

In the counter circuit 254, the clock signal C
The reference signal HD is generated by dividing LK. Further, a signal CNT indicating the count value by counting the cycle of the clock signal CLK is supplied to the timing signal generation circuit 255.

In the timing signal generation circuit 255, a latch control signal ENA is generated based on the signal CNT.
The signals are supplied to the latch circuits 209 and 220 and the signal switching circuit 240. Further, a latch control signal ENB having the same frequency and the opposite phase as the latch control signal ENA is generated, and the latch circuit 2
30.

In the FM modulation processing section 41 constituting the signal recording means shown in FIG. 2, a clamp process for setting the leading end of the synchronization signal and the pedestal level to a constant level with respect to the luminance signal YX, and to improve the S / N ratio. Is performed, a clipping process for preventing overmodulation in FM modulation, and the like are performed, and are FM-modulated into an FM-modulated luminance signal MY. This FM modulated luminance signal MY is supplied to the Y / C mixing unit 43. The signal recording means includes an FM modulation processing section 41, a Y / C mixing section 43, an amplifier 44 described later, and recording heads 45 and 46.

The carrier color signal C obtained by the Y / C separation section 11
IN is delayed by the color signal delay unit 30 and supplied to the frequency conversion unit 42.

In the frequency conversion section 42, the color signal delay section 30
The carrier chrominance signal CIN delayed by the above is down-converted into a low-frequency signal, and is supplied as a low-pass conversion carrier chrominance signal CW to the Y / C mixing unit. In the above-described color signal delay unit 30, the luminance signal YIN is processed by the luminance signal processing unit 20 and the FM modulation processing unit 41, and is converted into Y / C
The timing supplied to the mixing unit 43 and the carrier color signal CIN
Is processed by the frequency conversion unit 42 and the low-frequency conversion carrier color signal C
The delay time is set so that the timing of supplying W to the Y / C mixing unit 43 becomes equal.

The Y / C mixing section 43 mixes the FM modulated luminance signal MY and the low-frequency converted carrier color signal CW to form a recording signal W.
S is generated. The recording signal WS is supplied to the recording heads 45 and 46 via the amplifier 44 to be recorded on the magnetic tape 100.

A reproduction signal RS1 obtained by reproducing the magnetic tape 100 by the reproducing head 51 constituting the signal reproducing means is supplied to the switch section 55 via the amplifier 52, and the reproduced signal A reproduction signal RS2 obtained by reproducing the tape 100 is supplied to the switch unit 55 via the amplifier 54. The signal reproducing means includes reproducing heads 51 and 53, amplifiers 52 and 54, a switch unit 55, a high-pass filter 56, and an FM demodulation processing unit 5, which will be described later.
8 and so on.

In the switch section 55, the amplifier sections 52, 54
Are alternately selected and supplied to the high-pass filter section 56 and the low-pass filter section 57 as a reproduced signal RS. Therefore, the FM modulation luminance signal RY is obtained from the high-pass filter section 56, and the low-pass conversion carrier color signal RC is output from the low-pass filter section 57.
Can be obtained.

This FM modulated luminance signal RY is supplied to an FM demodulation processing unit 58. The FM demodulation processing unit 58 performs drop-out compensation for compensating for the loss of the signal and the FM modulation luminance signal R
A limiter process for removing the influence of the amplitude fluctuation of Y, a demodulation process of the FM modulated luminance signal RY, a de-emphasis process, and the like are performed to generate a luminance signal YDM. This luminance signal YDM is supplied to the signal switching circuit 201 of the luminance signal processing unit 20.

The analog luminance signal YR obtained from the luminance signal processing section 20 in the reproduction mode is supplied to the low-pass filter section 61.
To remove the components having a frequency equal to or higher than a predetermined frequency, and output the output luminance signal YOU from the video tape recorder.

The low-pass conversion carrier color signal RC obtained by the low-pass filter unit 57 is supplied to a frequency conversion unit 59. The frequency converter 59 converts the low-frequency converted carrier color signal RC into a carrier color signal CS. The carrier chrominance signal CS is supplied to the chrominance signal delay unit 30.

The chrominance signal delay section 30 converts the time required for processing the luminance signal YDM in the luminance signal processing section 20 and the luminance signal YR obtained by processing the luminance signal YDM in the luminance signal processing section 20 into a low-pass filter. The carrier chrominance signal CS is delayed by the time required for processing by the unit 61, and the output luminance signal YO is delayed.
It is output as a carrier color signal COUT from the frequency conversion unit 59 at the same timing as UT.

When the video tape recorder is set to the recording mode or the reproduction mode, the control unit 70 generates a mode signal MD indicating the operation mode and supplies the mode signal MD to the luminance signal processing unit 20. Note that the control unit 70 also controls other signal processing circuits and the tape running operation of the magnetic tape when the video tape recorder is set to the recording mode or the reproduction mode.

Next, the operation will be described. First, at the time of recording, the video input signal VIN is separated into a luminance signal YIN and a carrier chrominance signal CIN by the Y / C separation section 11, and the luminance signal YIN is supplied to the luminance signal processing section 20. The carrier chrominance signal CIN is supplied to the chrominance signal delay unit 30.

In the luminance signal processing section 20, the signal switching circuit 2
01, the luminance signal YIN is selected and the A / D conversion circuit 202 is selected.
Is converted into a digital luminance data signal DYS. Here, for example, when the luminance signal band of the video tape recorder is about 3 MHz (the cutoff frequency is about 2.7 MHz), the signal band after sub-sampling is about 2.7M.
Hz, the sampling frequency of the A / D conversion circuit 202 is set to about 10.8 MHz (in the case of the NTSC system) which is 686 times the horizontal scanning frequency fH.
Note that sampling of the A / D conversion circuit 202 is performed based on the clock signal CLK generated by the voltage controlled oscillation circuit 253. In this case, the clock signal CLK has a frequency of about 686 times the horizontal scanning frequency fH. 10.8M
Hz (in the case of the NTSC system). In addition,
Since sampling is performed at about 10.8 MHz,
The signal band is about 5.4 MHz, and sub-sampling is performed at about 5.4 MHz, so that the signal band after sub-sampling is about 2.7 MHz.

The luminance data signal DYS obtained by the A / D conversion circuit 202 is subjected to data conversion by the data conversion circuit 203 to facilitate the operation. Thereafter, the 1H delay circuit 204, the subtractor 205, the filter processing circuit 206, the delay circuit 207, and the subtractor 208 limit the band of the diagonal component as described above, and the obtained luminance data signal DYP is latched by the latch circuit 209. Supplied to

The latch control signal ENA supplied to the latch circuit 209 is a signal whose frequency obtained by dividing the clock signal CLK by １ ／ is about 5.4 MHz, and whose phase is inverted every line. Sub-sampling is performed by the latch circuit 209. This latch circuit 2
09 is selected by the signal switching circuit 242 and the data conversion circuit 24 is selected.
3, processed by the D / A conversion circuit 244, further selected by the signal switching circuit 245, band-limited by the low-pass filter circuit 246, and supplied to the FM modulation processing unit 41 as a luminance signal YX. For this reason, assuming that the luminance signal YIN has the frequency characteristic shown in FIG. 5A, the luminance signal YW is a signal in which the original signal component of the luminance signal YIN includes a folded component (a component indicated by oblique lines) as shown in FIG. It is said. here,
Since the luminance signal band of the video tape recorder is about 3 MHz (the cutoff frequency is about 2.7 MHz), the band of the luminance signal YW is limited by the low-pass filter circuit 246 and output from the low-pass filter circuit 246. As shown in FIG. 5C, the luminance signal YX has a cutoff frequency of about 2.
The signal is band-limited at 7 MHz. The luminance signal YX is recorded on the magnetic tape 100 after being processed by the FM modulation processing unit 41 and the like.

Next, the operation of reproducing a magnetic tape on which such a luminance signal is recorded will be described. Magnetic tape 100
And the luminance signal YDM obtained by the FM demodulation processing unit 58
Is supplied to the luminance signal processing unit 20. Note that the luminance signal YDM includes an aliasing component in the original signal component similarly to the luminance signal YX.

In the luminance signal processing section 20, the signal switching circuit 2
01, the luminance signal YDM is selected and the A / D conversion circuit 202 is selected.
Is converted into a digital luminance data signal DYS. In the A / D conversion circuit 202, about 10.
Sampling is performed at 8 MHz. Therefore, in the luminance data signal DYS, as shown in FIG.
And the aliasing component of the luminance signal YDM.

The luminance data signal DYS is subjected to data conversion by the data conversion circuit 203, and
After being set to YC, the 1H delay circuit 204 and the latch circuit 2
20.

In the latch circuit 220, the latch control signal E
The luminance data signal DYC is sub-sampled based on the NA. The luminance data signal DYL1 output from the latch circuit 220 is band-limited at a center frequency of about 2.7 MHz by the bandpass filter 221 and supplied to the signal switching circuit 240 as the luminance data signal DYM1. Therefore, as shown in FIG. 6B, the luminance data signal DYM1 has a component of the luminance signal YDM and a folded component of the luminance signal YDM having a predetermined bandwidth component having a center frequency of about 2.7 MHz.

In the subtractor 223, the timing is adjusted to the luminance data signal DYM1 and the luminance data signal DY is adjusted.
Since the band-limited luminance data signal DYM1 is subtracted from L1, the component of the subtracted data signal DT has the same component as that shown in FIG.

In the latch circuit 230, the latch control signal E
Based on the latch control signal ENB whose phase is opposite to that of NA, 1
The luminance data signal DYC delayed by one horizontal scanning period by the H delay circuit 204 is sub-sampled. The luminance data signal DYL2 output from the latch circuit 230 is processed by the bandpass filter 231 and has a center frequency of about 2.7 MHz and a predetermined bandwidth.
The signal is supplied to the signal switching circuit 240 as YM2. Here, the luminance data signal DYM2 is the latch control signal ENA.
The sub-sampling is performed based on the latch control signal ENB whose phase is opposite to that of the above, so that the component of the luminance signal YDM and the folded component of the luminance signal YDM have a component of a predetermined bandwidth centered at about 2.7 MHz. At the same time, the original signal and the aliasing component of the aliasing component have the same phase between the two lines, and the aliasing component has the opposite phase between the two lines.
It has the component shown in C.

In the signal switching circuit 240, the luminance data signal DYM1 and the luminance data signal DYM2 are alternately selected on the basis of the latch control signal ENZ. The subtraction data signal DT is added by the adder 241. Therefore, the signal switching circuit 242,
The luminance signal YR obtained via the data conversion circuit 243, the D / A conversion circuit 244, and the signal switching circuit 245 is shown in FIG.
As shown in the figure, the original signal of the luminance data signals DYM1 and DYM2, the folded component of the folded component, and the signal of the component of the subtraction data signal DT.

Further, the luminance signal YR is supplied to the low-pass filter section 61 shown in FIG. 2 and band-limited at a frequency having a cutoff frequency higher than 2.7 MHz, so that the high-frequency component (luminance signal The folded component of YDM) is removed. Therefore, the output luminance signal YOUT output from the low-pass filter unit 61 is a signal having a frequency component higher than about 2.7 MHz, which is equal to the luminance signal YIN, as shown in FIG. 6F. Therefore, the output luminance signal YOUT and the carrier chrominance signal COUT output from the video tape recorder are output.
, A high-resolution image can be obtained.

As described above, according to the above-described embodiment,
It is assumed that a signal is recorded on a magnetic tape in a state where the original signal includes a folded component.
Obtaining a luminance signal wider than the luminance signal band of the video tape recorder by using the aliasing component of the original signal and the aliasing component having the high-frequency component while removing the aliasing component by inverting the phase for each line. And a high-resolution image can be easily obtained. In the above-described embodiment, the case where a video tape recorder is used as the signal recording / reproducing device has been described.
The present invention is not limited to the video tape recorder, but may be another signal recording / reproducing device.

[0065]

According to the present invention, during the recording operation, a sub-sampling having an offset between lines is performed to generate a luminance signal having an original signal component and a folded component. It is recorded on a recording medium using a circuit. Also, at the time of the reproducing operation, by performing sub-sampling with an offset between lines on the luminance signal having the original signal component and the aliasing component obtained from the conventional signal processing circuit by reproducing the recording medium,
Since an output luminance signal of a wide band can be obtained from the original signal component and the aliasing component of the aliasing component having the high frequency component, FM
The image quality can be easily and easily improved without using a signal processing circuit or the like for performing modulation or FM demodulation having a wide band.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a sub-sampling operation.

FIG. 2 is a diagram illustrating an operation of the signal recording / reproducing apparatus according to the embodiment of the present invention;

FIG. 3 is a diagram illustrating a configuration of a luminance signal processing unit.

FIG. 4 is a diagram illustrating a band limiting operation of an oblique component.

FIG. 5 is a diagram illustrating a recording operation.

FIG. 6 is a diagram showing a reproducing operation.

[Explanation of symbols]

 11 Y / C separation unit 20 Luminance signal processing unit 30 Color signal delay unit 70 Control unit 201, 240, 242, 245 Signal switching circuit 202 A / D conversion circuit 207, 222 Delay circuit 209, 220, 230 Latch circuit 221, 231 Bandpass filter 223 Subtractor 241 Adder 244 D / A conversion circuit 246, Low-pass filter circuit 255 Timing signal generation circuit

Claims (9)

[Claims] At the time of recording a luminance signal, an analog input luminance signal to be recorded is sampled at a predetermined frequency and converted into a digital luminance data signal, and a composite luminance data including an original signal component and a folded component is converted from the luminance data signal. A signal, convert this composite luminance data signal into an analog luminance signal of a predetermined band, and record the analog luminance signal. At the time of reproducing the luminance signal, the reproduced analog luminance signal is sampled at the predetermined frequency to obtain a digital signal. The luminance data signal is converted into a luminance data signal, and the luminance data signal is processed to remove the aliasing component, and a composite luminance data signal including an original signal component and a component obtained by folding the aliasing component is obtained. A signal recording / reproducing method, wherein the signal is converted into a luminance signal and output. 2. The signal according to claim 1, wherein at the time of recording the luminance signal and at the time of reproducing the luminance signal, a sub-sampling having an offset between lines is performed to obtain a composite luminance data signal from the luminance data signal. Recording and playback method. 3. At the time of reproducing the luminance signal, band processing for passing a band component centered on a predetermined frequency from the luminance data signal is performed, and the data signal obtained by the band processing is converted for each line. 3. The composite luminance data signal is obtained by switching and selecting to remove aliasing components.
The signal recording / reproducing method described in the above. 4. When reproducing the luminance signal, a low-frequency component of the data signal is obtained by subtracting a data signal obtained by the band processing from a luminance data signal obtained by sub-sampling one line. The combined luminance data signal is obtained by adding the low frequency component of the data signal and the data signal from which the aliasing component of the data signal has been removed by switching and selecting the processed data signal line by line. The signal recording / reproducing method according to claim 3, wherein 5. An analog input luminance signal to be recorded is sampled at a predetermined frequency and converted into a digital luminance data signal. From this luminance data signal, an analog recording luminance of a predetermined band including an original signal component and a return component is provided. First signal conversion means for obtaining a signal; signal recording means for recording the recording luminance signal obtained by the first signal conversion means on a recording medium; and reproducing the recording medium to produce an analog reproduced luminance signal. A signal reproducing means for obtaining the reproduced luminance signal obtained by the signal reproducing means, sampling the reproduced luminance signal at the predetermined frequency and converting the sampled luminance signal into a digital luminance data signal, and processing the luminance data signal to remove aliasing components; A second signal converting means for obtaining an analog output luminance signal from a component obtained by folding the original signal component and the folded component. Recording and playback device. 6. The signal recording / reproducing apparatus according to claim 5, wherein said first and second signal conversion means perform sub-sampling with an offset between lines. 7. The apparatus according to claim 1, wherein said second signal conversion means has a band-pass filter, and said band-pass filter passes a component of a bandwidth centered on a predetermined frequency from said luminance data signal. The signal recording / reproducing device according to claim 5 or 6. 8. The signal according to claim 7, wherein said second signal conversion means removes aliasing components by switching and selecting a data signal obtained from said bandpass filter line by line. Recording and playback device. 9. The second signal conversion means subtracts a data signal obtained by processing the luminance data signal by the bandpass filter from a luminance data signal obtained by sub-sampling one line. It is assumed that data of a low-frequency component is obtained. By switching and selecting the data signal processed by the band-pass filter line by line, the data signal from which the aliasing component is removed and the data signal of the low-frequency component are added. 9. The signal recording / reproducing apparatus according to claim 8, wherein a data signal of a component obtained by folding the original signal component and the folded component is obtained.