JPH02146892A - Color television receiver - Google Patents

Abstract

PURPOSE:To adjust the contrast, color saturation and hue by controlling a control voltage of an amplifier amplifying a luminance signal and two color difference signals. CONSTITUTION:A DC voltage supplied from control terminals VR, VB is differentially changed be adjusting a variable resistor (R)9 in a contrast circuit added with a control voltage generating means and the ratio of amplification factors of amplifiers 6, 7 amplifying the two color difference signals is changed to able to adjust the hue. Moreover, the DC voltage supplied from the control terminals VR, VB is changed in the same ratio by adjusting a resistor R4 and the amplification factors of the amplifiers 6, 7 are changed in the same ratio to adjust the color saturation. Furthermore, the DC voltage supplied from control terminals Vr, VR, VB is changed in the same ratio by adjusting a resistor R1 and the amplification factors of the amplifiers 5, 6, 7 are changed in the same ratio to adjust the contrast.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to a color television receiver, and particularly to a television receiver capable of receiving high-definition television broadcasting. This invention relates to a color television receiver that allows adjustment of intensity and hue.

(Prior Art) Generally, in a color television receiver, by varying the amplification degree of a band amplification circuit provided in a color signal reproduction system and varying the output carrier color signal amplitude,
Hue is controlled by arbitrarily controlling the color saturation or by changing the phase shift relationship between the reference subcarrier and the carrier color signal applied to the color demodulation circuit.

On the other hand, high-definition television broadcasting, which is scheduled to take place in the next few years, will be superior to general television broadcasting in terms of definition and reproduction of faithful color images. No particular adjustment of color saturation or hue was required in the receiver. Therefore, a video signal reproduction system in a high-definition television receiver has a configuration as shown in FIG. 2, as an example.

In FIG. 2, radio waves received by a parabolic antenna 1 are demodulated by an SHF receiver 2, and further regenerated into a high-definition television signal by a decoder 3, resulting in a luminance signal Y and two color difference signals R-Y, B-Y. and are respectively supplied to the amplifier J1617 of the contrast circuit 4.

In the contrast circuit 4, by changing the amplification degree of each of the amplifiers 5, 6, and 7 at the same ratio using the DC voltage supplied to the control terminal 8, the contrast circuit 4 changes the amplification degree of each of the amplifiers 5, 6, and 7 at the same ratio. ! The contrast is controlled by changing the amplitude of the difference signal. Of the signals output from the contrast circuit 4, only the luminance signal Y' is supplied to the matrix circuit 12 via the adder 9, where it is converted into three primary color signals of red (R>, green (G), and blue (B)). .

The adder 9 includes DC regeneration circuits 13, 14, which will be described later.
At step 15, a reference pulse for controlling the brightness by changing the DC level of the DC-regenerated signal is supplied from the pulse generating circuit 10 and added to the brightness signal Y'. Then, the brightness is controlled by changing the amplitude of the reference pulse output from the pulse generating circuit 10 using the direct current pressure supplied to the H'rN element 11.

R and G output from the matrix circuit 12.

After the three primary color signals of B are subjected to DC reproduction based on the amplitude level of the reference pulse in the DC reproduction circuits 13, 14, and 15,
It is amplified by the video output circuits 16, 17, and 18 and output to the terminal 19.
20 and 21, and supplied to the cathode of a picture tube (not shown).

By the way, in high quality television receivers as well, ideally the color saturation,
It is desirable to be able to adjust the hue.

This is because once high-definition television broadcasting actually begins, it is expected that there will be a request to adjust the color saturation level 1 hue depending on the time and the situation. However, there has been a problem in that the high-definition television receivers that have been developed so far cannot meet such demands.

Therefore, when trying to adjust the color saturation and two hues in a high-definition television receiver, the color signal must be modulated and demodulated in the same way as in general television broadcasting, which increases the circuit scale and increases the However, there were drawbacks such as problems such as crosstalk and color distortion.

(Problems to be Solved by the Invention) As described above, high-quality television receivers have a problem in that color saturation and hue cannot be easily adjusted.

Therefore, the present invention is intended to eliminate the above problems.
The object of the present invention is to provide a color television receiver that can adjust color saturation and hue with a simple circuit configuration.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a decoder that obtains a luminance signal and two color difference signals from a color television signal supplied as an input, and a decoder that amplifies the luminance signal from this decoder, and a first amplifier whose amplification degree is variable at a control pressure of 1IIN; amplifying the two color difference signals from the decoder, respectively;
and a second one in which each amplification degree is variable by a control voltage. a third amplifier; and the first amplifier. Second. A matrix circuit that inputs the luminance signal output from the third amplifier and the two color difference signals and converts them into three primary color signals, and a video output means that supplies the three primary color signals output from this matrix circuit to the picture tube. A color television receiver equipped with a voltage variable circuit that varies the DC voltage, and the ability to divide the output voltage of this voltage variable circuit and differentially change the two divided DC voltages. a first voltage divider circuit; a voltage divider circuit that further divides one output voltage of the first voltage divider circuit and supplies the divided voltage to the first amplifier as a control voltage; It is possible to further divide the other output voltage of the dividing circuit and to differentially change the two divided DC voltages, and one divided voltage is supplied to the second amplifier as a control voltage. , the other divided voltage is +14
A second voltage dividing circuit is provided to supply the third amplifier as a control voltage, the contrast is adjusted by varying the voltage of the voltage variable circuit, and the color saturation is adjusted by varying the voltage of the first voltage dividing circuit. The invention is characterized in that the hue is adjusted by adjusting the voltage of the second voltage dividing circuit.

(Function) In the present invention, by varying the voltage of the second voltage dividing circuit, the amplification ratio of the two color difference signals can be changed to control the hue to a certain extent, and by varying the voltage of the first voltage dividing circuit, , the color saturation can be controlled by changing the amplification ratio of the luminance signal and the two color difference signals,
Further, by varying the voltage of the voltage variable circuit, the amplification degree of the luminance signal and the two color difference signals can be changed at approximately the same ratio, and the contrast can be controlled.

(Example) The present invention will be described below based on the example shown in the drawings.

FIG. 1 is a block diagram showing a color television receiver according to an embodiment of the present invention.

Similar to FIG. 2, FIG. 1 explains a high-definition television receiver, and the same components as in FIG. 2 are given the same reference numerals. That is, code 1 is a parabolic antenna, 2 is S
HF receiver, 3 is a decoder, 4 is a contrast circuit, 5
．． 6. 7 is an amplifier that can control the amplification degree, 9 is an adder, 10
11 is a pulse generation circuit for brightness control, 11 is a control terminal, 12 is a matrix circuit, 13.14.15 is a DC reproduction circuit, 16.17.18 is a video output circuit, 19゜20
．． 21 is an output terminal.

In this embodiment, the control terminals vy, vR, and VB of the amplifiers 5, 6.7 constituting the contrast circuit 4 are connected to control the contrast and color saturation.

And a control voltage generating means for controlling the hue 2t11J is provided. This control voltage generating means includes the voltage variable circuit 22. Voltage divider circuits 23, 25. It is composed of a voltage dividing circuit 24. The voltage variable circuit 22 is configured to vary the DC voltage 111-, and has a configuration in which a variable resistor R1 is connected between a power supply terminal VCC to which a constant DC voltage is applied and a reference potential point.

An output point a of the voltage variable circuit 22 is connected to a voltage dividing circuit 23 made up of resistors R2 and R3 and a variable resistor R4. In this voltage 991 circuit 23, the voltage output from the voltage variable circuit 22 is divided, and the two divided DC voltages are differentially varied by a variable resistor R4, and two output points are output.
I am trying to output each from c. The first output point of the voltage dividing circuit 23 is connected to the voltage dividing circuit 24 composed of resistors R5 and R6, and the divided voltage is derived from the connection point d of the resistors R5 and R6 to the control terminal VY. .

On the other hand, the second output point C of the voltage dividing circuit 23 is connected to a voltage valve v1 circuit 25 composed of resistors R7 and R8 and a variable resistor R9. In this voltage dividing circuit 25, the voltage output from the output point C is divided, and the two divided DC voltages are differentially changed by the variable resistor R9, and the output point e
, f, respectively. The divided voltages from the first and second output points e and f of the voltage dividing circuit 25 are:
They are respectively led out to control terminals VR and VB. The DC voltages derived from the control terminals V'/, VR, and VB are supplied to amplifiers 5, 6, and 7 constituting the contrast circuit 4, respectively.

In the contrast circuit 4 having the control voltage generating means configured as described above, by adjusting the variable resistor R9, the DC voltages supplied from the control terminals VR and VB are differentially changed. an amplifier 6 for amplifying the color difference signal;
The ratio of the amplification degrees of 7 is changed, resulting in a certain degree of control over the hue, which is particularly sufficient for fine-tuning human skin tones. In addition, by adjusting the variable resistor R4, the DC voltage supplied from the control terminal VY and the control terminals VR and VB changes differentially, so that the amplifier 5 that amplifies the luminance signal and the color difference signal The ratio of the amplification degree to that of the amplifier 6.7 changes, and as a result, the degree of color saturation can be controlled. Furthermore, by adjusting the variable resistor R1, the control terminal VY.

Since the DC voltages supplied from VR and VB change at approximately the same ratio, the amplification degree of amplifier 5.6.7 also changes at approximately the same ratio, making it possible to control the contrast.

In the above embodiment, the case where contrast, color saturation, and hue are adjusted in a high-definition television receiver is explained, but the present invention is applicable to a high-definition television receiver @
For example, the control voltage generating means described above can be used in common with a television receiver which is capable of receiving both high-definition television broadcasting and general television broadcasting.

[Effects of the Invention] As described above, according to the present invention, with a simple circuit configuration,
It becomes possible to adjust color saturation and hue even in high-definition television receivers.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a color television receiver according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional color television receiver. 3... Decoder, 4... Contrast circuit, 5.6
．． 7... Amplifier, 12... Matrix circuit, 16.
17.18... Video output circuit, 22... Voltage variable circuit, 23.25... Voltage dividing circuit, 24... Voltage dividing circuit. Procedure Nei 11 Official Document (Voluntary) Correction Statement

Claims (1)

[Claims] A decoder that obtains a luminance signal and two color difference signals from a color television signal supplied as an input; and a decoder that amplifies the luminance signal from this decoder, and the degree of amplification is variable with a control voltage. a first amplifier that amplifies the two color difference signals from the decoder, and
and inputting second and third amplifiers whose respective amplification degrees are variable with a control voltage, and the luminance signal and two color difference signals output from the first, second, and third amplifiers, In a color television receiver equipped with a matrix circuit for converting into three primary color signals and a video output means for supplying the three primary color signals outputted from the matrix circuit to a picture tube, a voltage variable circuit for varying a DC voltage; A first circuit that can divide the output voltage of the voltage variable circuit and differentially change the two divided DC voltages.
a voltage divider circuit that further divides one output voltage of the first voltage divider circuit and supplies the divided voltage to the first amplifier as a control voltage; and the first voltage divider circuit. It is possible to further divide the output voltage of the other one, and to differentially change the two divided DC voltages, supplying one divided voltage as a control voltage to the second amplifier, and supplying the other divided voltage as a control voltage. The divided voltage is the third
a second voltage divider circuit that supplies a control voltage to the amplifier, the contrast is adjusted by varying the voltage of the voltage variable circuit, and the color saturation is adjusted by varying the voltage of the first voltage divider circuit. A color television receiver characterized in that the hue is adjusted by adjusting the voltage of the second voltage dividing circuit.