Thursday, April 14, 2011

Process formation of RGB signal on TV

Basically the UOC is equipped with RGB or YUV input from external, so it is possible to use the DVD input. Selection of these inputs can be done internally within the IC.  But in the G7 and G7A chassis input YUV signal is not used, so in the ground.

RGB signal processing flow is described according to the image below :

iagram of the formation RGB signal
Diagram of the formation RGB signal

1. Signal Yint, uint, and Vint is derived from a series of color decoder and Y / C switch is fed into a series of YUV selector 1.

2. From YUV selector, sub-carrier signal color (U and V) is inserted into the chain matrix. In this matrix series component sub-carrier signal BY of the color (U signal) and BY component of sub-carrier signal color (V signal) in separate. Here the color difference signal in the form of the color sub carrier. GY signal generated by a combination of color difference signals RY and BY.

3. From YUV selector, luminan signal is passed to a series of black stretch. The working principle is to sharpen the series of black stretch black levels. Gray color in a certain percentage in drag to a black color so the color is sharper.

4. Three color difference signals (RY), (BY) (GY) and luminan signal (Y) are mixed and processed in RGB adder circuit to produce three primary colors red, green and blue (RGB).

5. RGBOSD formed in the UOC IC is used to display the OSD text. The selection and arrangement RGBOSD kontrast between RGB and composite signals is done by way of a switch by the internal microprocessor.

6. Three output video signal (RGB signal) is assumed as the current that flows to the CRT cathode. Drive level coming into the cathode tube is always diadjust by CCC loop (Continues Cathode Calibration) and feedback currents in pass to Black Current Input pin 50.

7. CCC loop works as a stabilizer against the black level and drive the cathode in a loop (continuous) to the RGB signal in order to obtain the proper offset and gain.

CCC Loop Application
CCC Loop Application

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