JPH05260501A - Color video signal output circuit - Google Patents

Abstract

PURPOSE:To improve the picture quality by executing optimization of the picture quality with regard to each of a composite signal and a Y/C signal which are outputted. CONSTITUTION:A carrier chrominance signal obtained through an encoder 2 from a Y/color difference signal of a high picture quality is subjected to band limit by a first band pass filter 4, synthesized with a luminance signal to which a delay conforming to the delay quantity of its filter is given by a delay line 3 and a composite video signal is outputted. Also, this circuit is constituted so that the carrier chrominance signal is allowed to pass through a second band pass filter 5, and outputted as a Y/C signal together with a luminance signal to which the corresponding delay is given by a delay line 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color video signal output circuit, and more particularly to a color video signal output circuit which encodes a high quality color video signal into another image quality and outputs it.

[0002]

2. Description of the Related Art High definition car television signals, such as M
Brightness / color difference (Y / color difference) in USE signal
C composite video signal and brightness / color (Y /
C) A so-called MUSE-NTSC is used as a color video signal output circuit for converting and outputting a separate video signal.
A circuit as shown in FIG. 3 is used in a video encoder of a converter. In the figure, 11 is a high-quality Y / color difference signal that is a MUSE signal output, and 12 is 3.58 MHz.
, A delay line (DL), and a band pass filter (BP).
F) and 17 are composite video signals (Composi)
te), 18 and 18 are separate video signals (Y / C)
Is.

Wideband color difference signals RY and BY in the Y / color difference signal, which is a high-quality color video signal, are converted by the encoder 12 into a color signal C on a 3.58 MHz subcarrier. After that, this C signal is 3.58M
Band limited through the BPF 14 of Hz,
And the Y signal that has been delay-compensated through the delay line 13 having the same delay amount as that of the composite signal 17 and the Y / C signals 18 and 18 are formed.

[0004]

In such a conventional color video signal output circuit, the Y / C signal output 18,
In order to obtain 18, the 3.58 MHz BPF 14 for obtaining the composite signal output 17 and the delay line 13 for compensating the delay amount are shared. Therefore, the image quality of the Y / C signal is the same as that of the BPF1 for the composite signal.
4 and the delay line 13, the C signal in the composite signal is limited to a narrow band, but a wide band can be used to some extent for the C signal in the Y / C signal, which is a signal for the S terminal. It was not suitable for the situation, and in the end, there was the fact that optimization was not performed for both signals. Therefore, it is an object of the present invention to improve the image quality by optimizing the image quality of each of the output composite signal and Y / C signal.

[0005]

According to the present invention, a carrier color signal obtained from an Y / color difference signal of high image quality through an encoder is band-limited by a first band-pass filter, and a delay matching the delay amount of the filter is provided. And a composite video signal is output by being combined with the given luminance signal, and the carrier chrominance signal is passed through another wider second band-pass filter, and the Y / Y signal is supplied together with the corresponding delayed luminance signal. C
It is configured to be output as a signal.

[0006]

As a result, a wide band C signal of the Y / C signal can be obtained and a separate video signal having an optimum image quality can be supplied.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is a high-quality color video signal, for example, a Y / color difference signal (Y, RY, BY) which is a MUSE signal output, Two
Is an encoder that modulates a supplied subcarrier having a predetermined frequency, for example, 3.58 MHz, with a color difference signal to generate a carrier color signal, 3 is a first delay line (DL-1),
4 is a first band pass filter (BPF-1), 5 is a second band pass filter (BPF-2), 6 is a second delay line (DL-2), and 7 is a composite video signal such as an NTSC signal ( Composite), 8 is Y / C
The signal is a so-called S terminal video signal (Y, C).

Here, in order to obtain the output of the NTSC signal 7, the band pass filter 4 is limited to the band of ± 0.5 MHz, the delay line 3 which is suitable for the delay amount is used, and the wide band Y / In order to obtain the C signal output, the bandpass filter 5 has a band of ± 1 MHz, and the delay line 6 that is suitable for the delay amount is used.

FIG. 2 is a block diagram showing a modified example of the embodiment of the present invention shown in FIG. 1, and the same components are designated by the same reference numerals. Here, the first delay line 3 in the embodiment of FIG. 1 is divided into a delay line (DL-2) 6 equivalent to the second delay line and a third delay line (DL-3) 9 and these The sum of the delay amounts of the two delay lines 6 and 9 is made equal to the delay amount of the band pass filter 4 to obtain the Y signal for the composite signal 7 from the output end of the delay line 9, and the dividing point, that is, the delay line. The Y signal of the Y / C signal 8 is obtained from the output terminal of 6. In this way, the delay line 6 can be commonly used for both outputs 7 and 8, and the image quality can be optimized for each output.

[0010]

According to the above structure, a color video signal having optimum image quality characteristics can be supplied to the output terminals for the composite signal and the Y / C signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a modification of the embodiment of the present invention shown in FIG.

FIG. 3 is a block diagram illustrating a configuration of a conventional technique.

[Explanation of symbols]

 1, 11 High-quality color video signal 2, 12 Encoder 3, 6, 9, 13 Delay line 4, 5, 14 Bandpass filter 7, 17 Composite signal 8, 18 Y / C signal

Claims (1)

[Claims] 1. An input terminal to which a luminance signal and a wideband color difference signal are supplied, an encoder for modulating a subcarrier having a predetermined frequency by the color difference signal to generate a carrier color signal, and the first carrier color signal. A first band pass filter for limiting the band, a first delay line for giving the luminance signal a delay equal to the delay amount of the first band pass filter, the first band pass filter and the first A composite output terminal to which a composite video signal obtained by combining both outputs of the delay line is supplied, a second band pass filter for limiting the carrier color signal to a second band wider than the first band, and A second delay line that gives the luminance signal a delay equal to the delay amount of the second bandpass filter; the second bandpass filter and the second delay line. Color video signal output circuit which both outputs of Rain is characterized by comprising a Y / C output terminal supplied separately.