JPS61263391A - Video signal recording device - Google Patents

Abstract

PURPOSE:To attain the recording of video signal with high resolution and excellent color reproducibility by offsetting the subcarrier frequency of the color difference signals provided adjacently to tracks by 1/2 of the horizontal scanning frequency which is adjacent with each other at every n-pieces of the adjacent recording tracks. CONSTITUTION:The inputted luminance signal Y is divided by a multiplexer 2 into signals of two channels which dot-interlace, and supplied respectively to filters 3 and 4. Unnecessary signals are removed by the filters 3 a 4 from the said signals, and they thereafter are modulated by FM modulator circuits 5 and 6 and added to adders a1 and a2. Meanwhile, color difference components B-Y and R-Y are supplied to multipliers M1 and M2, and are multiplied by f3 and f2 where ¦f2-f3¦=fH/2. The resulting signals, after being subjected to a band limitation by LPFs 7 and 8, are supplied to the adders a1 and a2 as being made not overlap in the band of the luminance signals. The color difference components and the luminance signals Y1 and Y2 are added with each other, and supplied to heads A1 and B1, and A2 and B2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a video signal recording device, and more particularly to a video signal recording device that sequentially records a video signal for one screen on each of n adjacent recording tracks. be.

[Conventional technology]

Conventionally, in a commonly used home video tape recorder (VTR), a luminance signal is FM-modulated in a high frequency band, frequency-multiplexed with a chroma signal frequency-converted to a low frequency band, and recorded. VTs that generally perform this kind of recording
R, for example, V of the well-known VH8 system or ρ format system.
In 'I'H, the exclusive band of the luminance signal is only about 3 MHz.

On the other hand, the band of the brightness signal of the television signal is NT
It is thought to be around 4.5 MHz in the SC system, and even more so in recent years for home color television receivers.
There are commercially available products that can reproduce this band. Therefore, according to the conventional VTR, the resolution has been reduced by the VTR.

Accordingly, attention is being paid to video signal recording apparatuses that sequentially record video signals for one screen on every n adjacent recording tracks.

FIG. 6 is a block diagram showing signal processing corresponding to the conventional home V1'R recording method.
4 is an adder, I, PF are low-pass filters, R-Y, B
-Y indicates a color difference signal, and Y indicates a frequency-modulated luminance signal.

Conventional signal processing is performed in a configuration as shown in FIG. 6, in which the two color difference signals R-Y and B-Y are orthogonally modulated and then low frequency converted from 55 BMHz to 629 KHz (in the case of VH8ffl). The signal is added to the frequency-modulated luminance signal Y by an adder and recorded.

[Problem that the invention seeks to solve]

In conventional color signal processing as described above, two color difference signals are orthogonally modulated at 58MHz, and then modulated at 40 fH (VH8
method), the low frequency band is converted and recorded. in this case,
Since information is stored in both amplitude and phase, phase fluctuations occur due to jitter and velocity errors in the electromagnetic conversion system, resulting in deterioration of image quality. Because of this, the usable band is only about 300 KHz, which poses a problem in that reproduced images with high color resolution cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a video signal recording device capable of recording a video signal having a high brightness S/N ratio and a high-resolution brown color image.

[Means for solving problems]

The video signal recording device according to the present invention has a video signal recording device that adjusts the color difference signal subcarrier frequencies of the adjacent tracks by an amount equal to the horizontal scanning frequency when recording a video signal for one screen on each recording track. These color difference signals and luminance signals are frequency-multiplexed and recorded.

[For production]

According to the above configuration, a wide band can be obtained for both the luminance signal and the color difference signal, and since the color difference signals can be separated between adjacent tracks, it is possible to record a video signal with high resolution and good gray reproducibility.

〔Example〕

FIG. 1 is a block diagram showing a first embodiment of the present invention. In the figure, Ml and M are multipliers, aI v
a2 is an adder, Y, Y2 are mutually offset sampled and frequency modulated luminance signals, and other symbols are the same as in FIG.

First, the luminance signal YI is offset sampled.

A method for obtaining Y2 will be explained. The luminance signal is divided into two channels of dot interlacing. FIG. 2 is a diagram showing how the luminance signal is divided into channels, where Y indicates the luminance signal, q indicates the sampling point for the first channel, and Δ indicates the sampling point for the second channel.

Here, the sampling frequency (Zfs) by the multiplexer, which will be described later, is set to be twice or more the highest frequency (fc) of the luminance signal, so that all information of the luminance signal can be extracted.

Also, when considering each channel, the sampling frequency f
s(>fc).

At this time, it is desirable that fs be an odd multiple of +fH. As is well known, this is a measure to prevent the lower side wave component of fs from being superimposed on the original signal and causing aliasing noise in the sampled signal, and sub-Nyquist sampling is performed for each channel. .

This will be explained below with reference to FIG. The input luminance signal (Y) is divided by the multiplexer 2 into two dot-interlaced channels as described above, and supplied to filters 3 and 4, respectively. Filters 3 and 4 include an LPF and a comb filter for removing the above-mentioned aliasing noise. The luminance signal of each channel from which unnecessary signals have been removed by filters 5 and 4 is FM modulated by FM modulation circuit 5.6, and Y□
, Y2 to the adder a1 r at.

The color difference signals B-Y and R-Y are applied to multipliers M, . . . M2. At the other input of this multiplier M1, a signal with a frequency f (in this case, f = 60 fH) is subjected to phase shift keying similar to that of a conventional V[S system VTR. Frequency f2. Input the signals f, respectively. Therefore, between the frequencies f2+f3 of these signals, there is l f2−
The relationship f, l = f H/2 is established. Here, fH indicates the horizontal scanning frequency. These signals are band-limited by LPFs 7 and 8 having characteristics shown by dotted lines in FIG. 4, so that they do not overlap the band of the luminance signal. In this case, the color subcarrier frequency is the conventional 40·fH (629KH
, ) to 60 f H (944 KHy), the signal band is the conventional,! We were able to expand the frequency from 100 KH to 600 KHz. Next, the color difference signal is a luminance signal Y
Y2 and adder "1sa2 are added, and heads A, B
□ and A2. It is supplied to B2.

Note that the two luminance signals Y1. Since Y2 is sampled offset from each other, by simultaneously combining the outputs of the adder alya2, a band twice as large as that of the conventional method can be obtained.

Figure 2 shows the arrangement of each head, with two sets of heads A□
, B□ and A2. B2 has an installation angle of 90° with respect to each other. In the case of the double high-definition mode, the rotational speed of the rotary head and the tape running speed are the same as in the conventional standard mode, and the tape format and azimuth angle are set as shown in Figure 3. can be configured to comply with the conventional VH8 standard, for example.

Since the spectrum of the signals at frequencies f2 and f mentioned above is as shown in Figure 5, crosstalk from adjacent tracks is removed by a comb filter, and synchronous detection is used to reproduce the two color difference signals. Just go.

In this embodiment of the invention, two sets of recording heads A□ and A
Since one field of signals is obtained by simultaneously combining the track signals of 2 and 2, twice the amount of information of the conventional luminance signal can be obtained. Further, as for the color difference signal, as described above, the amount of information about twice as much can be obtained by widening the signal band by changing the color subcarrier from 40·fH to 60·fH.

In the above embodiment, the luminance signals Y, Y2 are obtained by FM modulating two-channel signals offset sampled so as to interlace each other, but if a wideband luminance signal can be recorded, other channels may be used. It is also possible to take the form of a signal.

For example, it is also possible to obtain Y□+Y2 by dividing the entire band of the luminance signal into n parts and subjecting each part to FM modulation.

Furthermore, other head configurations or head arrangements, such as using a multi-rotation head, are also possible.

〔Effect of the invention〕

As explained above, in this invention, the chrominance signal side vehicle transmission frequencies of adjacent recording tracks are offset from each other by the horizontal scanning frequency, and 1. these chrominance signals and luminance signals are frequency-multiplexed and recorded. are doing. This reduces image quality deterioration due to phase fluctuations such as jitter and velocity errors that occur in the electromagnetic conversion system, and enables wideband recording of both color difference and luminance signals, greatly improving S/N.
This has the effect of providing high-definition images.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing how luminance signals are divided into channels, FIG. 3 is a diagram showing the head arrangement of this embodiment, and FIG. 4 is a diagram showing this embodiment. FIG. 5 is a diagram showing the band of each signal in this embodiment. FIG. 6 is a diagram showing the spectrum of the color subcarrier signal in this embodiment. FIG. 7 is a diagram showing the spectrum of the color subcarrier signal in this embodiment. FIG. 2 is a block diagram illustrating a conventional recording method. In the figure, A+-A2. Bl, B2 are magnetic heads Y1
．． Y is a luminance signal. Agent Patent Attorney 1) Haru Kitatake Figure 1 Figure 2

Claims (1)

[Claims] A device that sequentially records one screen worth of video signals on each of n adjacent recording tracks, in which a color difference signal whose carrier frequency is offset from each other by 1/2 of the horizontal scanning frequency, and a luminance signal are recorded on the adjacent recording tracks. A video signal recording device characterized by frequency-multiplexing and recording signals.