JPS61134196A - Recording device of digital color video signal - Google Patents

Abstract

PURPOSE:To code-convert a digital luminance signal and a digital chromaticity signal into a digital color video signal having less DC components without raising the recording frequency of the digital color video signal and to record it on a recording medium by code-converting said both signals into a digital signal each with less DC components. CONSTITUTION:An analog color video signal from an input terminal 1 is supplied to an A/D converter 2, which A/D converts said signal, and the digital color video signal (Y+C) is outputted. It is supplied to a comb-line filter 3, and separated to the digital luminance signal and the digital chromaticity signal. The digital luminance signal Y and the digital chromaticity signal C are outputted from an adder 5 and a subtractor 6, respectively. Then a line sequential signal is supplied to a 8-8 code converting circuit 10, and the digital luminance and digital chromaticity signals are converted into a digital signal having one sample of eight bits and a code having their word code disparity sum (CDS) which approximates to zero as near as possible or goes to zero. Continuously the line sequential digital video signal (Y+C)' subjected to the code conversion is supplied to a parallel/serial converting circuit 11, and converted into a serial signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a digital color video signal recording device suitable for application to a digital VTR.

[Conventional technology]

In conventional digital VTRs, in order to record a digital color video signal with a reduced DC component, for example, a digital video signal of 8 bits per sample is supplied to a code conversion circuit, and the digits of each binary digit are converted to 1. For example, 1 such that the difference between the number of 0s and the number of 0s, that is, CD5 (codeword disparity sum), becomes O or a number as close to O as possible.
However, according to such conventional digital VTRs, the samples are code-converted into 10-bit digital signals.
As the number of bits of the recording signal increases, the frequency of the recording signal increases, resulting in a decrease in recording density.

In view of these points, the present invention provides a digital color video signal that can be code-converted into a digital color video signal with less DC component and recorded on a recording medium without increasing the recording frequency. This paper attempts to propose a recording device.

[Means for solving problems]

The digital color video signal recording device according to the present invention includes a comb-type filter (3) that supplies a color video signal and obtains an m-bit digital luminance signal and a digital chromaticity signal, respectively;
It has a code conversion circuit (10) that supplies a digital luminance signal and a digital chromaticity signal and converts the codes into m-bit digital signals each having a small DC component. It is characterized in that a digital luminance signal and a digital chromaticity signal of m bits each are combined and recorded on a recording medium (14).

[Effect]

According to the present invention, since a color video signal is converted into a digital luminance signal and a digital chromaticity signal and then code-converted, a digital color video signal with a small DC component can be obtained without increasing the number of bits per sample. This can then be recorded.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIG. (2) is an A/D converter, and the input terminal (1
) is supplied, A/D converted, and a digital color video signal (Y+C) is output. This digital color video signal (Y + C'') is supplied to a comb-shaped filter (3) and separated into a digital luminance signal and a digital chromaticity signal.
3) is composed of a delay line (4) having a delay amount of one horizontal period (IH), an adder (5), and a subtracter (6), as is well known. The adder (5) outputs a digital luminance signal Y, and the subtracter (6) outputs a digital chromaticity signal C.

(7) is another IH delay line, for example, which delays the digital chromaticity signal by IH. The digital luminance signal and the IH-delayed digital chromaticity signal are supplied to a changeover switch (8) and switched for each IH to obtain line sequential signals of the digital luminance signal and the digital chromaticity signal. (9) is a switching signal generator that supplies a switching signal to this switch (8).

This line sequential signal is supplied to an 8-8 code conversion circuit (10) to convert a digital luminance signal and a digital chromaticity signal into C
1 samples are converted into an 8-bit digital signal of a code whose DS is O or as close to 0 as possible. That is, as is clear from FIG. 2A, the dynamic range of the digital color video signal (Y+C) is 0 to 255 levels, as shown in FIG. 2B.

As is clear from C, the dynamic range of the digital luminance signal Y and the digital chromaticity signal C has plenty of room for the range of 0 to 255 levels, so even if the number of bits in one sample is not changed, the digital luminance signal Y And the digital chromaticity signal C can be easily converted into a digital signal with a code having a CDS of 0 or a value close to it. Note that in FIG. 2, b indicates a burst signal.

The code-converted line-sequential digital video signal (Y+C)' from the 8-8 code conversion circuit (10) is supplied to the parallel-to-serial conversion circuit (11), where it is converted into a serial signal, and then sent to the amplifier (12). The magnetic tape (14) is supplied to the rotating magnetic head (13) built in the tape guide drum through the magnetic tape (14).
The recorded data is recorded so as to form an inclined track.

Note that the analog color video signal is supplied to a comb filter (3) to be separated into an analog luminance signal and an analog chromaticity signal, and then supplied to an A/D converter, respectively, to generate a digital luminance signal and a digital chromaticity signal. You can also try to get .

〔Effect of the invention〕

According to the present invention described above, there is provided a digital color video signal recording device that can code-convert a digital color video signal into a digital color video signal with less DC component and record it on a recording medium without increasing the recording frequency. Obtainable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining the same. (1) is the input terminal, (2) is the A/D converter, (3) is the comb filter, (7) is the IH delay line, (8) is the changeover switch, (10) is the 8-8 code A conversion circuit (11) is a parallel-to-serial conversion circuit, (12) is an amplifier, (13) is a magnetic head, and (14) is a magnetic tape.

Claims (1)

[Claims] A comb-type filter that supplies a color video signal to obtain an m-bit digital luminance signal and a digital chromaticity signal, respectively; and a comb filter that supplies the digital luminance signal and digital chromaticity signal to produce an m-bit digital signal with a small DC component, respectively. and a code conversion circuit for code conversion, and the m-bit digital luminance signal and the digital chromaticity signal each code-converted by the code conversion circuit are combined and recorded on a recording medium. Digital color video signal recording device.