JPH0334275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color television receiver.

NTSC system (including PAL or SECAM system)
Conventional color television receivers that receive RGB and RGB television signals have separate adjustment volume controls for each type of processing circuit to control the contrast and brightness of the image. As a result, the number of volume controls has increased, and the placement of the volume has become a problem, as they are not attached to the front of the television set, but instead are attached to the back. In addition, in terms of operability, when viewing TV images and text multiplex signals at the same time, such as in teletext broadcasting, it is always difficult to use two
If the two volumes were not adjusted, the balance would be off, making it extremely complex and difficult to understand, resulting in poor operability.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a color television receiver that can improve the operability for image adjustment, reduce the volume of volume installation space, and reduce costs.

That is, this invention uses NTSC as an input signal.
TV signals such as PAL, SECAM, etc.
In a television receiver that has input signals for two signal systems, the RGB system, image control such as adjustment of image contrast and brightness is performed using a common adjuster for both the NTSC television signal system and the RGB signal system. It is something.

An embodiment of the invention is shown in the drawings. That is,
In this color television receiver, the output ends of the NTSC processing circuit _M1 and the RGB processing circuit _M2 are connected to a signal switch S, the signal switch S is connected to a cathode ray tube CRT, and the first variable Contrast volume VR ₁ which is a resistor and bright volume VR ₂ which is a second variable resistor
is commonly connected to the processing circuits M ₁ and M ₂ ,
These circuits M ₁ and M ₂ are controlled.
In other words, the regulator connects the first variable resistor VR ₁ and the second variable resistor VR ₂ inserted between the DC voltage source B and the ground, and the variable terminal of the first variable resistor VR ₁ to RGB. The contrast adjustment circuit is connected to the DC voltage supply terminals of the transistors _{Tr 1 to Tr 3} of the R, G, B signal input stage of the NTSC signal processing circuit M ₂ and is also connected to the contrast adjustment circuit Q ₁ of the NTSC signal processing circuit M 1. The variable terminal of the second variable resistor VR ₂ is connected to the transistor Tr ₄ of the R, G, B signal output stage of the RGB signal processing circuit.
- DC level setting means for brightness adjustment connected to the base bias setting terminal of Tr ₆ and connected to the brightness adjustment circuit Q ₂ of the NTSC signal processing circuit M ₁ .

To explain the operation, RGB system (digital) signals R, G, and B are inputted with negative polarity to the bases of transistors Tr ₁ to _{Tr 3} of circuit M ₂ , and are set by a contrast volume VR ₁ as a DC level setting means for contrast adjustment. The amplitude is changed by the voltage whose impedance is converted by the transistor _Tr7 . next,
The voltage is inputted to the base of the impedance conversion circuit of transistors Tr ₄ to _{Tr 6} through the DC cut capacitors C ₁ to _{C 3} , and the impedance is converted to the voltage from the bright volume VR ₂ by the transistor Tr ₈ of the bright adjustment DC level setting means. , the clamp is applied by transistor Tr ₉ . this circuit
The cathode ray tube is output through the output signal switch S of _M2 .
Supplied to CRT. In addition, the circuit M ₁ processes the NTSC signal with the chroma processing IC circuit IC, and controls the contrast adjustment circuit Q ₁ and brightness adjustment circuit Q 2 with the outputs of the volume VR 1 and VR ₂ , and controls the contrast adjustment circuit Q ₁ and the brightness adjustment circuit Q ₂ by switching the signal switch S. Supplied to cathode ray tube CRT.

As described above, the color television receiver of the present invention uses the NTSC system and the NTSC system as input signals.
In devices that process RGB television signals,
Since a common image control adjuster is provided for each processing circuit, it is possible to improve operability, reduce the installation space by halving the number of volumes, and reduce costs.

[Brief explanation of drawings]

The drawing is a circuit diagram of an embodiment of the present invention. CRT...Cathode ray tube, M ₁ ...RGB signal processing circuit, _M2 ...NTSC signal processing circuit, VR ₁
...Contrast volumetric volume which is the first variable resistor, _VR2 ...Bright volume which is the second variable resistor, S...Signal switch, _Tr1 to _Tr6 ...Transistor, _Q1 ...Contrast adjustment circuit , _Q2
...Bright adjustment circuit.

Claims (1)

[Claims] 1. A cathode ray tube, a signal switch connected to the cathode ray tube, an NTSC signal processing circuit that supplies an output signal to the cathode ray tube through the signal switch, and an RGB signal that supplies a signal to the cathode ray tube through the switching operation of the signal switch. a processing circuit, the NTSC signal processing circuit, and
a regulator that is commonly inserted into the RGB signal processing circuit and controls the contrast, brightness, etc. of the image of the cathode ray tube displayed through the signal switch, and the regulator is inserted between the DC voltage source and the ground. A first variable resistor and a second variable resistor, and a variable terminal of the first variable resistor are connected to the R, G,
DC level setting means for contrast adjustment connected to the DC voltage supply terminal of the B signal input stage transistor and connected to the contrast adjustment circuit of the NTSC signal processing circuit, and the variable terminal of the second variable resistor connected to the RGB a DC level setting means for brightness adjustment connected to the base bias setting terminal of the R, G, B signal output stage transistor of the NTSC system signal processing circuit and connected to the brightness adjustment circuit of the NTSC system signal processing circuit;
A color television receiver characterized in that the contrast, brightness, etc. are controlled by DC level adjustment using the first variable resistor and the second variable resistor.