Automatic frequency control circuit selectively using frequency-divided local oscillator signal or pilot signal

摘要: An automatic frequency control (AFC) circuit receives input signals and generates converted by mixing the with a local oscillation signal. extraction extracts pilot signal, if present, from provides signal to switch. A divider divides of output voltage oscillator, frequency-divided The switch is compared reference in phase comparator which comparison result controls controlled oscillator. If not selects construct phase-locked loop stabilize Alternatively, an AFC includes for selectively dividing included Various frequencies can be received altering division number divider.