Subcarrier signal generator for use in stereo tuners

摘要

First and second rectangular signals which are 90 DEG out of phase with each other are derived by comparators and an RS flip-flop from a symmetrical triangular wave signal. The first rectangular signal is halved in frequency by a frequency divider, the output of which is supplied to an adder. The second rectangular wave signal is also delivered to the adder. An output from the adder is converted by a bandpass filter into a sine-wave subcarrier signal in synchronism with a stereo pilot signal in an FM stereo tuner. The first and second rectangular signals may be derived by a pair of D-type flip-flops from a pulse signal.