JPS62277884A - Video signal recorder - Google Patents

Abstract

PURPOSE:To record a color signal while expanding the frequency band of the signal into nearly twice by applying frequency conversion to a high frequency component of an inputted color signal into a low frequency side so as to compress the band of the color signal. CONSTITUTION:The frequency component below 1MHz is eliminated by a high pass filter 5 and the result is fed to a frequency multiplex circuit 6. On the other hand, (R-Y), (B-Y) signals inputted to input terminals 2, 3 are subjected to frequency limit to, e.g., below 800kHz by low pass filters 7, 9 and the result is fed to band compression circuits 8, 10. The band compression circuit 8 or 10 applies frequency conversion to the high frequency component of an input color signal so that the frequency spectrum of the high frequency component of the color signal inputted to a recording circuit section is subjected to frequency interleaving at an interval of one over an integral number of a frequency fv (vertical scanning frequency) between frequency spectrums of the low frequency component of the inputted color signals. Thus, the band of a color signal is expanded to nearly twice in comparison with the conventional color under recording.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a video signal recording device such as a video tape recorder (VTR).

2. Description of the Related Art Since around 1970, VTRs employing the so-called color under method (or carrier color signal low frequency conversion method) have been put into practical use as home VTRs or business VTRs.

Problems to be Solved by the Invention Conventional color under type VTRs set the frequency of the color subcarrier of the carrier color signal to about 629 KHz or about 68 KHz.
8K) Iz for recording and reproduction, the color signal (or color difference signal) band is 350K llz ~ 500K
There is a problem that the width is as narrow as flz.

Means for Solving the Problems The present invention solves the above-mentioned problems and, in order to record a wideband color signal, frequency converts the high frequency components of the input color signal to the low frequency side in the recording circuit section. This device is equipped with a band compression circuit that compresses the band of the color signal by performing the following steps.

Effects According to the present invention, the frequency band of the color signal to be recorded is approximately twice as wide due to the above-described configuration.

Embodiment Hereinafter, an embodiment of the video signal recording apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the main configuration of the present invention. The input video signals include a luminance signal Y, a color difference signal (R-Y), and a color difference signal (B-Y
), but Y, I, Q or R, G, B
Alternatively, the same effect can be obtained by using a signal obtained by decoding a carrier color signal. The Y signal is input to input terminal 1, (RY)
The signal is input to input terminal 2, and the (B-Y) signal is input to input terminal 3. Y signal input to input terminal 1,
The FM modulator 4 converts the signal into an FM signal. For example, F.M.
Deviation frequency from 3.4Mfiz to 4.4MHz
shall be. Next, frequency components below 11'1llz are removed by a high-pass filter 5 and supplied to a frequency multiplexing circuit 6. On the other hand, the (RY) signal input to the input terminal 2 is frequency limited to, for example, 8QOKHz or less by a low-pass filter, and is supplied to the band compression circuit 8. In addition, the (B-Y) signal input to the input terminal is filtered through a low-pass filter 9.
For example, the frequency is limited to 800 KIIz or less,
The signal is supplied to the band compression circuit 10. The band compression circuits 8 and 10 have a frequency of fA=24fH+ (v (where fB: horizontal scanning frequency, fB: vertical scanning frequency, and fA is set to, for example, n=28.m=o). Note that n and m can be arbitrary integers.) A first carrier signal is supplied from the input terminal 11.The output signals of the band compression circuits 8 and 10 and the input terminal 12 A second carrier signal whose input frequency is r2 (for example, frequency f2 is set to 629kHz)
are input to the quadrature two-phase modulator 13. here,
The output signals of band compression circuits 8 and 10 are quadrature two-phase balanced modulated. The burst gate circuit 14 also receives a horizontal synchronization signal separated from the second carrier signal and the luminance signal input to the input terminal 1 by the horizontal synchronization signal separation circuit 15, which is further delayed by a delay circuit 16 and obtained. A burst flag signal is input. The burst gate circuit 14 supplies the bursted second carrier signal to the adder 17 . Also, the quadrature two-phase balanced modulation signal is also input to the adder 17.
2. added to and synthesized. The signal is supplied to the frequency multiplexing circuit 6. The output signal of the frequency multiplexing circuit 6 is frequency-multiplexed with the FM signal and the quadrature two-phase flat i-cut modulation signal, and is supplied as a recording current to the recording head 18 and recorded on the magnetic tape 19.

Note that, as described below, the band compression circuit 8 or 10 is configured such that the frequency spectrum of the high frequency component of the color signal input to the recording circuit section is between the frequency spectrum of the low frequency component of the input color signal, It includes a circuit that converts the frequency of the high frequency component of the input color signal so as to perform frequency interleap at an interval of an integer fraction of fV (vertical scanning frequency).

An example of its configuration is shown in FIG. The band compression circuit 8 or IO includes a high-pass filter 101 connected to the input terminal 22, a low-pass filter 102, a multiplication circuit 103 connected to the high-pass filter 101 and the input terminal 23, and the multiplication circuit 103, an adder circuit 106 connected to the low-pass filter 102, a low-pass filter 105 connected to the adder circuit 04, and an output terminal 24 connected to the low-pass filter 105. . FIG. 3 schematically shows an example of the frequency spectrum of the signals of each part in FIG. 2. The input terminal 22 of the band compression circuit 8 is connected to a low pass filter 7 with a frequency of 900
A (R-Y) signal band-limited to KHz is input, and an example of its frequency spectrum is shown in FIG. 3a, and an example of its detailed frequency spectrum is shown in FIG. Change the passband of high-pass filter 01 from 400KHz to 80KHz.
When the frequency is 0 KHz, the frequency spectrum of the output signal of the high-pass filter 01 becomes as shown in FIG. 3C.

Furthermore, the frequency fA of the first carrier signal input to the multiplication circuit 103 is also written in FIG. 4C. At the output end of the multiplier circuit 103, a signal having a frequency spectrum as shown in FIG. 4a is obtained, and the detailed spectrum is shown in FIG. If the passband of the low-pass filter 02 is set from DC to 400Kilz, a frequency spectrum as shown in FIG. 4C is obtained at its output end, and a detailed spectrum thereof is shown in FIG. 4D. As mentioned above, by setting the frequency of the first carrier signal at fA = 24f++ + fy, the frequency-converted high-frequency components (shown in Figure 4 a and b) and the low-frequency components of the input signal (shown in Figure 4 a and b) Figure 4c,
d) maintains a frequency interval of −f, resulting in a frequency interleap relationship. That is, at the output end of the adder circuit 104, the frequency band from DC to 800KHz is maintained in the frequency band from DC to 800KHz.
This means that a signal in which the signal up to IIz is band-compressed is obtained. Similar band compression is performed in the band compression circuit 1o.

For band compression, the frequency of the first carrier signal was selected, but for example, the frequency of the first carrier signal may be changed to another frequency f.
You can choose B and choose . In this case, the frequency difference between the frequency spectrum corresponding to FIG. 4 (a) and the frequency spectrum corresponding to FIG. 4 (d) is 1 □ r v.

Furthermore, as another frequency fc, f(=n・fIl, however, the field is inverted every time, or every 27 fields is inverted, or every field has a 90" lag phase, 90" lag phase, etc., isometrically, fA or Similarly to fIl, a frequency at which frequency interleaving is established may be set.

Note that although the band compression described above utilizes frequency left by heterodyne, it is also possible to similarly compress the band by performing frequency folding using a sub-Nyquist sampling technique.

In the case of frequency folding using a multiplier circuit (not shown), the frequency of the carrier signal for folding is set to 2m+, for example, f4=n'-f+=fv.

You can select such as. Also, fB=n −fB However, L/
, inversion every two fields, or 90' phase delay (delayed phase) for each field. Just choose a frequency that is twice the frequency.

Note that the band compression described above uses frequency interleaving that is an integer fraction of the vertical scanning frequency, but the same result can be obtained even if frequency interleaving that is an integer fraction of the horizontal scanning frequency is used. Bandwidth compression is possible.

As the frequency of the quadrature two-phase modulation carrier (second carrier signal rz), 629 Hz was used as an example, but this is 40 r H as used in the low-pass conversion color subcarrier frequency of the VH3 standard. The same is true for a 90'' phase shift for each scanning line. Also, the same applies if a low-pass conversion color subcarrier frequency of the β standard, U standard, or 81m video standard is used as r2.

Effects of the Invention By using frequency interleap to perform band compression of color signals and then performing quadrature two-phase modulation to perform so-called color under recording, conventional color under recording (for example, VH3 standard, β standard , 8 votes 1 video standard or U
It has great industrial value because the color signal band can be expanded to approximately twice that of the standard (e.g., standard).

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of main parts in an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the configuration of the band compression circuit 8, and FIGS. FIG. 3 is a frequency spectrum diagram showing frequency spectra of signals of each part. 6... Frequency multiplexing circuit, 8... Band compression circuit, 10... Band compression circuit, 13...
... Quadrature two-phase modulator, 14 ... Burst gate circuit, 17 ... Adder, 101 ... High pass filter, 102 ... Low pass filter,
103... Multiplication circuit, 104... Addition circuit, +05... Low pass filter. Name of agent: Patent attorney Toshio Nakao Haka1-N
TS Mi N Figure 3'r-fB-1 "As 4 Figure

Claims (3)

[Claims] (1) A device for recording a luminance signal and a color signal, in which the frequency spectrum of the high-frequency component of the color signal input to the recording circuit section is between the frequency spectrum of the low-frequency component of the input color signal. , f_V (vertical scanning frequency) (vertical scanning frequency). , f_V (vertical scanning frequency). (2) As a frequency conversion circuit that converts the high-frequency components of the input color signal, there is a high-pass filter that separates the high-frequency components from the input color signal, and the output signal of the high-pass filter and the frequency are f_A. The multiplication circuit that performs multiplication with a certain carrier and the frequency are f_A=n・f_H+[(2m+1)/2]f_V (where n and m are arbitrary constants, f_H is the horizontal scanning frequency, and
_V is a vertical scanning frequency); a first low-pass filter that separates low-frequency components of the input color signal; and an output signal of the multiplier circuit and the low-pass filter. and a second low-pass filter that removes unnecessary components from the output signal of the adder circuit. Signal recording device. (3) As a frequency conversion circuit that converts the high-frequency components of the input color signal, there is a high-pass filter that separates the high-frequency components from the input color signal, and the output signal of the high-pass filter and the frequency are f_B. The multiplication circuit that performs multiplication with a certain carrier and the frequency are f_B=n・f_H+[(2m+1)/4]f_V (where n and m are arbitrary constants, f_H is the horizontal scanning frequency, and
_V is a vertical scanning frequency); a first low-pass filter that separates low-frequency components of the input color signal; and an output signal of the multiplication circuit and the low-pass filter. and a second low-pass filter that removes unnecessary components from the output signal of the adder circuit. Signal recording device.