Single chip TV colour decoder - operates with NTSC, PAL or secam and automatically switches its own circuits accordingly

摘要

A TV receiver colour decoder, constructed as a single integrated circuit, identifies whether is is being fed with NTSC, PAL or SECAM colour signals and automatically changes over its own circuits to suit. Amplitude modulated NTSA or PAL signals are previously separated from SECAM frequency modulated signals and fed into different inputs of the decoder. The decoder separates the colour synchronising signal and identifies the system from its characteristics. Controlled by line synchronising pulses, it performs whichever type of switching is required between lines. The signal is then demodulated and decoded to give the three colour signals, R,G.B. as outputs. Two quartz resonators, three LC resonant circuits and a delay line are required to be connected to the circuit.