The luminance signal from the other to "Input Select" switching outputs into sync separator stage , after clamping the composite synchronizing signal separated amplified , along with the delivery line and vertical sync separator / field frequency dividing circuit , so that pulse oscillation frequency from the line out field frequency pulses to synchronize , synchronize the field frequency pulse as a sub-screen vertical sync pulse from the ic803 {36} pin output . Another composite sync signal and the noise cancellation signal processing , phase in afc phase detector line voltage controlled oscillator with (vco) line oscillation signal generated by comparing the oscillation pulse line vco phase adjustment for realized line synchronization . vco color subcarrier oscillator as well as by the reference signal control p / n decoder output formats to accommodate different needs of the line frequency . After the oscillation signal by the pulse forming line dividing shaping circuit , as a sub- screen line sync pulses from the ic803 {39} pin output . Rc { 37 } pin external components , constitutes the phase detector filter network , change the network RC components will directly affect the sub-screen synchronization range . The manifold line voltage controlled oscillator capacitor built-in, no external oscillator components. Another line from the sub-screen , field, color burst sandcastle pulse consisting of { 40 } feet from the output of the circuit is not used .

 

Second, the sub-picture forming circuit

 

1 ª± sprite a / d, d / a conversion and effects processing ; PIP TV technology today , whether it is " RF " PIP, or "Video" PIP have adopted the all-digital mode , the unit no exception.

ic802 is an analog / digital (a / d) converter integrated circuits . The ic803 {49}, {50}, { 51 } the sub- picture signal is output from pin ic802 {23}, {21}, {19} pin input , via respective first clamp clamped to the same level. The luminance signal from the 6 -bit A / D converter sampling and holding , the quantized into six binary digits (y00-y05), then after an adjustable delay from the output pin 7 to 2 ; into two color difference signals are each 6 -bit A / D converter, after subtraction of handling mixed into a four digit binary code (uv00 ~ uv03) by the {11 } ~ 8-pin output

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