JPH02154595A - Chrominance signal processing circuit - Google Patents

Abstract

PURPOSE:To simplify a circuit by outputting a modulated chrominance signal in the case of an NTSC system and a PAL system and either of (R-Y) signal or (B-Y) signal in the case of an SECAM system. CONSTITUTION:A polarity switching switch 3, an OR logical gate 9, a control switching switch 12, a color polarity discrimination signal input terminal 6 and an SECAM/PAL switching signal input terminal 10 are provided. The polarity switching switch 3 switches the polarity of the (R-Y) signal with the color polarity discrimination signal to be controlled by an SECAM/PAL switching signal and sends the signal to an encode switch 4. The encode switch 4 switches the (R-Y) signal, the (B-Y) signal and respective inversion signals with the switching signal to be controlled by the SECAM/PAL switching signal and outputs. Thus, the signal to be modulated into the chrominance signal in the case of the NTSC and PAL can be outputted, the signal to be converted into one system in case of the SECAM can be outputted, and the circuit is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit for processing a color signal of a video signal converted into a digital signal, and relates to an NTSC.

1) It relates to a digital color encoder that is compatible with three systems: AL and SECAM.

[Conventional technology]

Conventionally, the color signal of the small screen of the video signal produced by the special image device of the NTSC system was published in the magazine "Telehi Technology" 198.
As described in "About digital technology" on pages 26 to 31 of the August 2007 issue, the signal was obtained by digitally processing the RY signal and the BY signal. FIG. 6 shows a block diagram of the NTS C digital color encoder, and FIG. 7 shows a timing chart. R-
The signal input from the Y signal input terminal 1 and the signal input from the BY signal input terminal 6 are inverted by inverters 2 and 7, respectively. R-Y signal, B-Y signal and each inverted signal,
Input to encoder switch 4, 41'sc input terminal 1
Sequentially R-Y, B-Y, -(]<Y) at a color sub-forward transmission frequency (hereinafter referred to as fsc) that is four times higher than 1 manually.
, -(B-Y) and output as a color signal from the color signal output terminal 5. The timing chart in FIG. 7 shows the RY signal at input terminal 1, the BY signal at input terminal 6, and the color signal at output terminal 5.

[Problem to be solved by the invention]

The above-mentioned conventional technology is limited to the NTSC system, and there are problems in that it does not take other systems into consideration, and that it must be compatible with other systems and compatible with other systems.

The purpose of the present invention is to provide an N T
An object of the present invention is to provide a color signal processing circuit for SC and PAL systems.

Another object of the present invention is to provide a color signal processing circuit that is compatible with both the NTSC system and the PAL system.

Another object of the present invention is to provide a method for externally switching the system with a small number of control signals when built into an integrated circuit.

Another object of the present invention is to provide a color signal processing circuit that can handle three types of signal input by providing an external S E CAM color encoder.

Another object of the present invention is to reduce the number of output signal pins when built into an integrated circuit by providing a single output system in all three systems.

[Means to solve the problem]

In order to achieve the above purpose, the R-Y signal, the BY signal and each anti-%λ signal are used as a color polarity identification signal and S E CA M
/PAL switching signal is used to control the switching.

[Effect]

, 3.

The polarity changeover switch is used for the inclusion discrimination (R-Y by the ij number) controlled by the SECAM I)
Switch the polarity of the signal and send the signal to the encode switch. The encode switch switches and outputs the RY signal, the BY signal, and each inverted signal using a switching signal controlled by the SECAM/PAL switching signal.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIG.

Compared to Fig. 6, polarity changeover switch 3° OR logic gate 9
．． Control changeover switch 122 color polarity identification signal (hereinafter referred to as ID signal) input terminal 6° SECAM/PAL changeover signal input terminal 10 is newly provided. A signal input from the R-Y signal input terminal 1 is input to a polarity changeover switch 3 and an inverter 2. The signal inverted by inversion@2 is manually inputted to the polarity changeover switch 3 as a -(RY) signal. 11. The 1 and D signals manually inputted from the multiplier input terminal 8 are inputted manually to 9 to 01<logic game 1. SECA on the other side of Kate
M/PAL switching signal input terminal] Off from 0, 4.

When the switching signal is input, the ID signal is transmitted to the polarity selector switch 3 during PAL, and the ID signal is not transmitted during S E CAM. The output of the polarity changeover switch 3 is switched between encoder 1 and switch 4 depending on the ID signal during PAL.
-(R-Y signal to terminal C and terminal C, respectively)
) signal or -(R-Y) signal.

It can be switched to pass the RY signal or not. At the time of S E CAM, the RY signal is passed through the terminal A, and the -(RY) signal is passed through the terminal C. Incidentally, at the time of N'r SC, the ID signal input terminal 8 is set so that the output of the polarity changeover switch 3 is the same as that at the time of SECAM.

The B-Y signal input from the B-Y signal input terminal 6 is input to the terminal B of the encoder 1 to switch 4, and the -(B-Y) signal inverted by the inverter 7 is input manually to the terminal B. As described above, signals are input to C and C according to each method.

The ID signal and 4. are sent to the control changeover switch 12. The 4fsc signal input from the fsc input terminal 11 is manually input to the SEC
AM]) 4 by the AL switching signal
-fsc signal is outputted as iD times signal in SECAM. In addition, in the case of NTSC, the SECAM/PAL switching signal input terminal]0 is set so as to output a 4 fsc signal like PAL. The encode switch 4 is configured to switch between PAL and NTSC depending on the output of the control changeover switch 12.
The terminals are switched from A to B to C to D for each SC.

Also, in SECAM mode, terminal A→B is switched by T and D signals.
It is controlled to switch to The signal switched by the encode switch 4 is sent to the PA from the color signal output terminal 5.
In the case of L, NTSC, a modulated color signal is output, and in the case of SECAM, the RY signal and the B-Y signal are switched and output in one horizontal scanning period.

According to this embodiment, an output modulated into a color signal can be output when NTSC and PAL, and a signal converted into a single system can be output when S E CAM.

FIG. 2 shows a timing diagram 1- of the signal output from the color signal output terminal 5 according to this embodiment.

Color signal (1) is used for NTSC, and color signal (1) for PAL.
1) and color signal (2) are switched to "horizontal scanning" period by the ID signal, and during SECAM, the color signal (3) and color signal (4) are switched and output at each period of "horizontal scanning" by the ID signal. .

Next, a second embodiment of the present invention is shown in FIGS. 3 and 4.

Encoder 3 is the color signal processing circuit shown in the first embodiment. FIG. 3 is a block diagram of video signal processing in the case of PA, L and NTSC systems. Encoder 13
Since the output is a modulated digital color signal, it is converted into an analog color signal by a digital-to-analog converter (hereinafter referred to as an A/D converter) 4, and is input to the Y/CFI converter 17.

On the other hand, the digital signal input from the luminance signal input terminal 15 is converted into an analog luminance signal by the A/D converter 16,
The Y/C mixer 17 mixes the signal with a color signal, and outputs the signal from the video signal output terminal 18 as a video signal. Also SECAM
In the case of the SEC method, as shown in Figure 4, compared to Figure 3, the SEC
This can be handled by adding an AM encoder 19. The output of the encoder 13 is alternately switched between the RY signal and the BY signal for each period of horizontal scanning.

This signal is converted to analog by the D/A converter 14, and S
Modulated into a color signal by the ECAM encoder 19, 7
.

The mixed signal is mixed with a luminance signal by a Y/C mixer 17 and outputted from a video signal output terminal 18. According to this embodiment, by using the encoder 13 shown in FIGS. 3 and 4 as a circuit that can be switched by a control signal as explained in the first embodiment, it can be used for three types of video signal processing. .

Next, a third embodiment of the present invention will be explained with reference to FIG. Compared to FIG. 4, changeover switches 21 and 22 are newly provided.

The changeover switches 21 and 22 are controlled by the signal from the SECAM/PAL changeover signal input terminal 10, and the S
The ECAM encoder 19 is used.

According to this embodiment, video signal processing can be performed on input signals of NTSC, PAL, and SECAM systems.

〔Effect of the invention〕

According to the present invention, color signals can be modulated when using the NTSC and i'AL systems, and can be converted to a single output when using the SECAM system. It's effective, 8.

Furthermore, since it can be used for both the NTSC system and the PAL system, there are economical effects such as a reduction in the cost of sharing the circuit when creating a circuit compatible with both systems.

In addition, since it is possible to switch between three methods using only two external signals, the number of pins can be reduced when built into an integrated circuit.
It has the effect of reducing prices.

Furthermore, since the use of an external SECAM encoder enables processing corresponding to three types of input signals, there are economical effects such as simplification of the circuit and reduction in the number of parts by two using a shared circuit.

In addition, in any of the three systems, since the output can be made into one system, the number of output pins can be reduced when built into an integrated circuit, which has the effect of reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG. 2 is a timing chart thereof. Figures 3 and 4 are block diagrams of the second embodiment; Figure 3 is a block diagram of the second embodiment;
Fig. 5 is a block diagram of the third embodiment. Fig. 6 is a block diagram of the conventional fluorocarbon system, 9., 10. !!It is I. 3... Polarity changeover switch, 4... Encode switch, 12... Control changeover switch, 19... SECAM encoder, 21. 22... Changeover control switch, 13... Encoder.

Claims (1)

[Claims] 1. In a circuit that processes a color signal of a video signal converted into a digital signal, the modulated color signal is processed in the case of the NTSC and PAL systems, and the R-Y signal and the B- signal in the case of the SECAM system. A color signal processing circuit comprising means for outputting either one of the Y signals. 2. In claim 1, the means inverts the polarity of the R-Y signal every other horizontal scanning period when using the PAL system;
A color signal processing circuit characterized in that polarity is not inverted when using the NTSC system. 3. A color signal processing circuit characterized in that when the circuit according to claim 1 is integrated, the method is switched by applying two control signals from the outside. 4. The color signal processing circuit according to claim 1, wherein a color encoder for SECAM is provided externally, and the color encoder is controlled so as to operate only during SECAM, thereby supporting three types of input signals. 5. In claim 1, the means comprises NTSC and PA
When using the L method, the R-Y signal and B-Y signal are modulated into color signals, and when using the SECAM method, the R-Y signal and the B-Y signal are modulated into color signals.
A color signal processing circuit characterized in that a color signal output is output as one system by switching a Y signal with a color polarity identification signal.