JPH02192286A - Color television receiver - Google Patents

Abstract

PURPOSE:To dissolve the problem of human skin color displayed yellowy by providing a skin color correction circuit between an output terminal of a B-Y signal of a color difference signal demodulation circuit and a B-Y signal input terminal of a matrix and color output circuit. CONSTITUTION:A resistor R14 is inserted between earth and a connecting point of a resistor R12 and a capacitor C13 of a B-Y signal transmission line. The resistor R14 is inserted to the B-Y signal transmission line, resulting that the B-Y signal of a color difference signal demodulation circuit 8 is divided at a ratio of R14/(R12+R14). Thus, by setting the resistor R14 to a proper value, the same color as the standard IC is obtained from an IC with a high color temperature. Thus, the color of an object IC is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is based on an IC with a standard color temperature of 6500°C.
This invention relates to a color television receiver that uses an IC with a high color temperature and does not have a hue adjustment knob.

2. Description of the Related Art Generally, a color television receiver is constructed as shown in FIG. A signal applied to the antenna terminal 1 of the receiver is tuned by a video receiving circuit 2, and the audio signal is sent to the audio receiving circuit 3, and the video signal is sent to the color demodulation circuit 5. Here, each is demodulated, and the audio and video are reproduced by the speaker 4 and the color picture tube 7. Here, the synchronous deflection circuit 6 is for creating a synchronous signal,
This is sent to a well-known deflection coil, not shown.

As a conventional example, let us consider a case in which two ICs, a color difference signal demodulation circuit and a matrix and color output circuit, in the color demodulation circuit 5 have a configuration as shown in FIG. The color difference signal demodulation circuit 8 has a color temperature of 6500°C or higher, and the gain distribution of the output RY and BY signals is as follows: Gt (1-V) i Gt ts-n -a + b
・-・'(1) G- of matrix and color output circuit 9
The matrix gain that creates the Y signal is Gx(*-v>:Gz<*-v>--c: -d-
- (2), then from Fig. 3 and equation (2), the color difference signal G-Y (G~green, Y~luminance signal) signal is G-
Y=-aXcX (RY)-bXdX(B-Y)
......It is represented by (3). This chromaticity diagram is as shown in FIG.

Problems to be Solved by the Invention By the way, FIG. 5 shows an IC with a standard color temperature of 6500°C.
A chromaticity diagram is shown when the color difference signal demodulation circuit 8 is used. However, the matrix and the IC of the color output circuit 9 are the same as the conventional ones. The gain distribution in this case is as follows.

In other words, what can be seen from FIG. 5 or equation (4) is that I
This means that the higher the color temperature of C, the greater the ratio of the BY signal to the RY signal.

Therefore, a problem arises in that the G-Y signal becomes large and the color of human skin becomes greenish, that is, yellowish.

The present invention is based on these problems and aims to easily eliminate these drawbacks.

Means for Solving the Problems The present invention directly captures the fact that the hue of a color TV without a hue adjustment knob is determined by the color temperature of the IC, and adjusts the R-Y and B-Y color difference signals. Matrix, G-
The feature is that before creating the Y signal, only the B-Y signal is divided by a resistor, and by increasing (R-Y)/(B-Y), it easily solves the problem of yellowish skin tones. do.

Operation By inserting the voltage dividing resistor of the present invention for countermeasures against yellow skin tone after the B-Y signal output of the IC of the color difference signal demodulation circuit, and by changing the value of the resistor, (R-Y)/
CB-Y) can be set to an appropriate value, thereby
A suitable skin color can be obtained. Furthermore, this can also accommodate changes in matrix gain when various ICs are used in the matrix and color output circuits.

Example An embodiment of the present invention will be described below.

FIG. 1 shows the configuration of essential parts according to an embodiment of the present invention, and in this figure, parts common to those in FIG. 3 are given the same reference numerals.

As can be seen from FIG. 1, this configuration is almost the same as the conventional one shown in FIG. The difference is that .

In this way, by inserting the resistor R14 into the BY signal transmission line, the BY signal output from the color difference signal demodulation circuit 80 is voltage-divided into RIa/(R+t+R14). Therefore, the value of (RY)/(B-Y) was smaller than that of standard IC due to the high color temperature of conventional IC, but by setting resistor RI4 to an appropriate value, As a result, even an IC with a high color temperature can produce the same chromaticity as a standard IC.

Then, in order to produce the same chromaticity as standard IC, RI
I will explain how much 4 should be set.

This can be easily determined, and from Figure 4, in the conventional model, G-Yl-, /a"Xc"+b"Xd"...
-(s), but in this configuration, G-Y =, /a"Xc"+b"Xd"XRt<"/
(R+a+R+z)'...(6) Therefore, according to Figure 5, the standard one is more like (
If R14 is calculated by assuming that equations 6) and (7) are equal, the following is obtained.

Furthermore, even if the matrices and color output circuits 9 are not the same as described above, but are different, the calculation will be a little complicated, but by determining the value of RI4, it is possible to obtain the same chromaticity diagram as the standard IC. can.

Effects of the Invention As described above, according to the present invention, although the structure is simple, just inserting one resistor, by setting the value of the resistor to an appropriate value, the target IC can be realized. It has an extremely excellent effect of being able to change the chromaticity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color television receiver according to an embodiment of the present invention, FIG. 2 is a block diagram of a color television receiver, and FIG. 3 is a diagram of a conventional color difference signal demodulation circuit, matrix, and color output circuit. Block diagram, Figure 4 is a chromaticity diagram of a color television receiver using a conventional IC, Figure 5 is a chromaticity diagram of a color television receiver using a conventional IC.
The figure is a chromaticity diagram of a color television receiver using a standard IC or improved according to the present invention. 8... Color difference signal demodulation circuit, 9... Matrix and color output circuit, R8... Resistor. Name of agent: Patent attorney Shigetaka Awano Idiot 1 R14-state

Claims (1)

[Claims] This is a color television receiver without hue or adjustment knobs, and is equipped with a color difference signal demodulation circuit implemented as an IC with a higher color temperature than the standard 6500°C color temperature IC, and the B-Y of this color difference signal demodulation circuit A color television receiver characterized in that a skin color correction circuit is provided between a signal output terminal and a B-Y signal input terminal of a matrix and color output circuit.