Phase identifier for chrominance signal in PAL decoder - uses phase detector connected to integrator to indicate phase

摘要

The phase identifier, for the chroma signal in a PAL decoder in a colour television receiver, has a phase detector receiving the burst signal and the output of the local oscillator. The phase detector output is connected to an integrator. The phase detector inputs are multiplied together in the detector to give two 180 deg.-shifted outputs. The integrator controls the local oscillator via a low pass filter. The changes in the phase detector output voltage are used directly to obtain the phase indicating pulses irrespective of any other purpose that the detector output may be used for.