JPS5925492A - Recording system of color video signal - Google Patents

Abstract

PURPOSE:To obtain a color reproduced picture of high S/N, by obtaining sum and difference signals of two color difference signals and mixing the signal obtained extracting those sum and difference signals alternately for each horizontal scanning line with a luminance signal after the modulation of frequency. CONSTITUTION:Color difference signals A and B are supplied to color difference signal input terminals 7 and 10 respectively and then given to an adder 9 and a subtractor 12 through LPF8 and 11 to obtain the sum and difference signals respectively. These sum and difference signals are supplied to the input terminal of a line switch 13. The switch 13 selects the output of the adder 9 with an odd line and the output of the subtractor 12 with an even line respectively. The output of the switch 13 undergoes an addition and an FM modulation through an adder 19 and an FM modulator 14 respectively. Then the output of the switch 13 is supplied to an adder 5 with its undesired component deleted through an LPF15 and added with the FM-modulated luminance signal to be recorded on a tape by a video head 6. In such a way of recording, I and Q signal components are stored for each line. This ensures the reproduced picture of high S/N in a reproduction mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording system for color video signals in video tape recorders, etc. - Structure of conventional example and its problems Conventionally, as a recording system for color video signals, The most famous method is the low-frequency summer recording method.In this method, the luminance signal of the color video signal is angularly modulated6, for example, FM modulated, in the higher frequency range, and the carrier color signal is converted into the lower frequency range. The frequency is converted to, for example, several hundred kiloliters (z), and the same wave number is multiplexed to the FM modulated t:# degree signal and recorded as a spectrum as shown in Fig. 1. In this method, Carries color signals.

Since the luminance FM signal is recorded with a bias as shown in Fig. 1, the low frequency conversion carrier color signal recorded in nU is subjected to amplitude modulation due to contact between the video head and the tape during playback. (After that, when the signal is input to the television receiver, side-scanning noise and color signal saturation changes occur. In other words, AM noise increases and the carrier color signal UU') S/
This will cause deterioration of N.

This phenomenon has become more pronounced as video tape recorders have become more compact and high-density G8 recording of shorter wavelengths and fall tracks has been performed.Recently, this recording method has reached its limit. child.

In addition, as an H/J method that is affected by the amplitude modulation of this method, the carrier color signal is adjusted on two axes (t, 2, 0)] color difference signal (for example, -Y signal, etc.), and then output these two color difference signals to each horizontal scanning line (hereinafter referred to as
This is a line-sequential method in which two color difference signals are switched in the "l-in" and this signal is FM-modulated on the lower frequency side. Figure 2 shows this spectrum. However, this method However, this method has the disadvantage that the vertical resolution is low because one color difference signal is discarded for each line.

As with the low frequency conversion recording method mentioned above, FM modulation means is used instead of bias recording, so even if amplitude fluctuations occur due to uneven contact between the head and tape during playback, this amplitude fluctuation will be suppressed by the limiter during FMi adjustment. can be removed, and AM noise does not occur.

Purpose of the Invention The present invention (also to solve the above-mentioned drawbacks of the conventional method, is not affected by amplitude fluctuations like the low frequency conversion method, and does not discard one color difference signal for each line like the line sequential method). The purpose of the present invention is to provide a method that can record data using almost the same bandwidth and bandwidth.

Structure of the Invention The color video signal recording and reproducing system of the present invention achieves the above objects (1) and (2) by recording the sum (A-1-13) and difference ( A-B
), frequency-modulate the signal obtained by alternately extracting the sum component and difference component for each horizontal scanning line, and convert this frequency-modulated y, = signal to 1. What is the signal obtained by frequency-modulating the luminance signal? If the 11 degree signal is recorded with another video head, the local wave number will be changed to 1. 'if (,) is mixed with the f-knee signal and recorded by the same video head.

Description of examples An embodiment of the present invention will be described below based on the drawings.

FIG. 8 is a basic diagram of the present invention (a configuration diagram of a recording system, FIG. 4 is a detailed explanatory diagram of the present invention 1M), and FIG. 5 is an example of a recording system.

In Figure 3, (υ is e.g. from a Kafuu camera) l
+l1 degree a input terminal, (7) C1 is color difference (Fi
What is this color difference signal?

This is a signal before obtaining the conveyed color image 1 through quadrature two-phase adjustment within the camera. uO is an input terminal for a signal including at least a horizontal synchronization signal as a synchronization signal. Although not shown here, the signals at these input terminals are those in which a luminance signal and a carrier color signal are separated from a five-color color video signal, and the phase is synchronized with the burst signal of this carrier color signal to create a continuous wave. However, similarly to a color television receiver, a single synchronizing signal may be obtained by separating a synchronizing signal from a single color difference signal obtained by synchronous detection and the luminance signal.

This FIG. 8 will be explained in detail. (1) is the input terminal for the luminance signal or color video signal, (2) is the input terminal for the luminance signal, and the luminance signal is separated by 1 low frequency modulator (for example, in Figure 5). 4~ as shown
The frequency is modulated to 5 MHz, and unnecessary low-frequency components are removed, for example, by bypass fill (4).
In step 5), it is added to the color signal FM wave (described later) and sent to the video head (
6) is recorded on the magnetic tape. - Signals A and B are respectively input to the color difference signal input terminals (7) C1,). Signals A, B are, for example, I, Q or R-Y, B-Y
It is. Signals A and B are each low-pass filtered (3)
For example, 500KHz (7) suitable for recording due to Qυ
The output of C1O is guided to an adder (9) and a subtracter@, respectively.

A refiner (9) adds signals A and B, and a subtracter (2) subtracts B from signal A. In other words,
(a) in Figure i4 represents the output of the low-pass filter (2) in Figure 8, (b) shows an example when signal A is an I signal, and (c) shows an example when signal B is a Q signal. Each number (1, I!・
...) indicates the line number. That is, the adder (
9), the output of subtractor 0■ becomes) and Q10, respectively.

and (dl) are connected to the respective input terminals of line switch 03.This line switch 0
3, a synchronization signal including at least a horizontal synchronization signal is input. The signal from the input terminal OQ is divided by 172 (17
) gives 1/2 fl ((however, fH is the horizontal synchronization frequency)
The square wave signal is switched by the t signal. In other words, each line is made to select a signal) and Q10. The output of the line switch 91 is as shown in FIG. In other words, in Figure 4, the adder (9
) is the output of the subtractor 0 on even numbered lines, but the output of the subtractor 0 (
E) can be selected. In this method, polarity switching is required during playback.For example, a color sync generator (11 This pulse is added as a color sync in adder 09, and the fourth
The signal should be as shown in figure (g). In other words, (for every 2' fins, f, (color sync) is transmitted as well as the 1q degree signal. The output signal (t) of the adder 4 is FM modulated by the FM modulator σ, As shown in the figure, for example, FM waves in the range of 800KHz -], MH2,
Unnecessary components with high wave numbers are removed by a low-pass filter Q9, and then added to the luminance FM signal by the adder (5) and recorded on a tape by the video head (6).

In this way, the recording deviation includes the I signal and Q signal components for each fin, and there is no need to discard one dye signal for each line, as in the conventional T line sequential method.1:
Therefore, vertical resolution does not decrease.

Now, as a detailed explanation of the present invention, the low bass fill (
8) In this case, the band of oυ is 500KHz, and the same wave number modulation range of FM controller 4 is 800KJ (Z~IMHz).

Moiré may be a problem depending on the modulation method, but
For this purpose, it is preferable to employ a conventionally known high-frequency conversion method. In other words, after setting the FMK modulator to 100 KH2 at 8 MHz, for example, remove unnecessary components through a band pass filter of 7.4 to 8.6 MII z.
The frequency is converted using a stable signal of 6 about 1.5MtlZ.
O) If passed through a low pass filter, 900KHz -l
-1001(l(z) FM wave can be obtained.

To reproduce one signal recorded in this manner, it is sufficient to perform the procedure shown in FIG.

In FIG. 6, the signal shown in the spectrum G in FIG. 5 is reproduced from the video head (6), and the bypass fill signal is reproduced. ) and low-pass filter to separate the luminance FM signal and color FM signal, and both of these FM signals are separated into FM signals.
By passing through the demodulator (C), (2) and the low-pass filter (2), reproduced luminance No. 43 and reproduced color difference signal (K) are obtained. Brightness here (B θ is 3M, for example) Iz
, the color difference signal is 500 KHz, and the same signal as shown in FIG. 4 (G) is reproduced as shown in FIG. 7 (G). The signal is guided to a hook separator (a) and a color sync remover (b).The color difference signal from which the color sync has been removed is guided to a horizontal scanning delay (2), an adder (←), and a subtracter (b). In addition.

1 Horizontal scanning delay (A) output also goes to adder (to), subtracter (to)
c). In other words, the color sink has already been removed, and the color sink has already been removed, as shown in Figure 7. f
ff. Then, the adder (to) adds the t signal (g) delayed by one horizontal scan and the undelayed signal [(t), but the sink is r (i).The subtracter (b) adds (t) - (t). ) is calculated.First, we will simplify the explanation here.

Since the color difference information has a strong correlation for each line, (G) is shown as (Male 1), and q→ is shown as C5[). In other words, A
, B are the color difference signals in FIG. 8, and since the correlation is strong, it can be assumed that each line has the same information. Then, the output of the adder (2) becomes (/'3. On the other hand, the subtracter (■) calculates (su) - (/ri, and obtains (wo). Qari is the color difference signal A
but.

(ヲ〕), the color difference signal B is obtained. However, it can be seen that the polarity of this B is reversed at the end.
wo) is a 1/2 amplifier a with double the amplitude (kana na q)
'i cn obtains the A and B signals that are the same as the input signal.

The B signal is directly connected to the input of the line switch via polarity inversion Ia@. This line switch (goods)
is shown in Figure 7 (the polarity like Takumi is also the same as the human signal (7)
This is the one that converts it into a .33 signal.

To explain the switch operation in more detail, the horizontal synchronizing signal is separated from the reproduced luminance signal via the horizontal synchronizing signal unit (e), and the signal is used to reset the MB unit (e) by 1/2. Then, determine the polarity of the rectangular wave of 1ifl'/2fll. And this signal is the 7th (8) (wo)
Since the polarity inverter (B) is operated to select the output only when the negative line is on, the line switch (C) output number is selected.

A color difference signal B as shown in FIG. 7(n) is obtained.

Both reproduced color values A and B obtained by lζ in this way are as follows.

Color encoder stabilizes 1 for example if 8.58M
Using the Hz oscillator output, it is quadrature 2 (U) modulated and added to the reproduced luminance signal in a 4 adder (7), and is sent to the output terminal C1υ.

You can receive a reproduced color video newsletter. The spectrum is shown in FIG.

In this way, it is not necessary to discard the color difference value -1 of one of the two color difference values 1''A and B in the conventional line sequential method, and amplitude fluctuations are not affected as in the conventional reduction conversion. However, since this is FM recording (IJ), this amplitude fluctuation can be removed using a limiter during playback, making it possible to obtain a color reproduced image with low AM noise and a good S/N ratio within almost the same recordable range as before. .

In the above example, one color difference value band is 500Ki (z is Example C
As I explained earlier, in NTSC, the I signal is 1.5.
MHz+() range, and in this PAL signal R-Y
, B-γ signal band is 1.5 MHz for both signals.

First, to make it a wider range.In other words, in order to apply it to higher-performance devices, it is necessary to set the FM carrier frequency of the color difference signal to 1.5MHz or higher.Then, the luminance FM carrier frequency also has to be It becomes necessary to set the frequency to a relatively high frequency.If the device has a margin for relative speed, such a frequency arrangement can be used, but generally there is not much margin.Carrier 1.! [!!To make the frequency higher is to record at a shorter wavelength,
Generally, the S/N deteriorates approximately proportionally.

However, if the track width of the head is narrowed, the track width and S
/N is proportional to the square root. I'm here.

To consider a recording and reproducing device with wide M resolution and still high performance.

You can do it like this:

Hereinafter, this example is shown in FIG. 9, an example of its recorded spectrum is shown in FIG. 10, and an example of its recorded trajectory is shown in FIG.

In FIG. 9, the same numbers as those in FIGS. 8 and 6 represent the same operations, and detailed explanation thereof will be omitted.

For example, assume that the band of low bass filter (2) is 4 MHz. However, the input signal is the camera's luminance signal 1 color difference input low pass filter ([1) (+1) band of 1.5 MH
z and swee.

The FM modulator (3) for brightness is explained in FIG. 8 as shown in FIG.

The output directly causes the trajectory θ( ) shown in FIG. 11 to be formed by one side of the brightness video head. On the other hand, the color difference signal with a band of 1-5 MHz is processed according to the present invention, and the FM modulators a to 3.4 to 5.0, for example, as shown in FIG.
The trajectory (AI) shown in FIG. 11 is formed using a video head (2) different from 1bllfi, which is a MHz modulated biconcave FM wave. Regeneration C? In this case, the luminance FM signal is reproduced from the video head θ, and the FM demodulator (a) and the low frequency filter 34 demodulate the FM signal to obtain a reproduced luminance signal. And this leads to the adder So. At this time, if the band of low bass fill (c) is 4MHz, then 1.-
The luminance band of Tal is 4M)l'Z. - The color difference signal FM is reproduced from the video head, and is FM demodulated by an FM demodulator and a 1.581Hz low-pass filter to obtain a wideband color difference signal. And this is for color sink separator and color sink remover)
guided by.

Now, paying attention to FIG. 11, the track pitch Tp is divided into two channels, the trajectory of the luminance multiplied old track and the trajectory of the color difference signal track (AI), and the track width "I"
"wy, Twc l Twy > Twc tv. For example, Twy = 2' Twc + rub. In this case, the color (7) S/N seems to decrease, as shown in Figure 10).

By recording only one signal on one channel, the band is less than half of the luminance signal band, so a wide modulation range can be obtained, and the band can be increased without deteriorating the S/N. It is.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(υTwo color difference signals A as in the conventional line sequential method.

There is no need to discard one of the B color difference signals line by line, and even if the amplitude change M+IJ is received as in conventional low-frequency conversion,
At the 1st moment of the FM recording, this swing, l is set with the limiter during playback.
1lli! Fluctuations can be removed, and a color reproduced image with less AM noise, that is, with good s/H, can be obtained within almost the same recordable range as the conventional method.

(2) Not only can it be used for home use, it can also be applied to high-performance models such as ENG, and it can also be used for NTSC signals only.
It can also be applied to I'AL signals and SECAM signals.

[Brief explanation of the drawing]

FIG. 1 is a spectrum diagram of a conventional low frequency conversion recording system, FIG. 2 is a spectrum diagram of a conventional line sequential recording system, and FIGS. 8 to 11 show embodiments of the present invention. Fig. 8 is a block diagram of the basic recording system of the recording method of the present invention, Fig. 4 is an explanatory diagram of Fig. 3, Fig. 5 is a recording diagram of the recording system shown in Fig. 8, and Fig. 6 is a reproduction system. 7 is an explanatory diagram of FIG. 6, FIG. 8 is a diagram of the output spectrum of the regeneration system, FIG. 9 is a block diagram of another embodiment, and FIG. 10 is a diagram of another embodiment. FIG. 9 is a spectral diagram of the washi plane, and FIG. 11 is an explanatory diagram of the recording locus of the apparatus shown in FIG. (1) Input terminal for luminance signal, (3) α・V...
Frequency modulator・(5)(9)α9・・・Adder, ([1
lG1 wheel...video head, (7) Ql...1
, Q signal input terminal, Q signal...subtractor, C13...
・Line switch agent Yoshihiro MorikiFigure 7Figure 2Figure 3Figure 4Figure 2

Claims (1)

[Claims] 1. Create the sum (A+B) and difference (A-B) of colorimetric difference signals from the two color difference signals A and B of the carrier color signal, and calculate the sum component and the difference for each horizontal fixed line. Frequency modulation is performed on the signal obtained by extracting the components alternately. This frequency-modulated signal is frequency-modulated to the luminance signal and recorded using a video head separate from the first signal.The first half is frequency-modulated to the luminance signal, mixed with the second signal, and recorded using the same video head. Color video doubles the old recording method.