Apparatus for tuning offset signals by controlling a tuner based on a difference in frequency of signals tuned by that tuner

摘要

A frequency counter obtains frequency data by measuring the frequency of an optionally offset broadcast signal tuned by a tuner having a VCO. A microprocessor is used to determine the frequency difference between the optionally offset signal and the previously tuned signal based on the frequency data measured for each signal, and controls the oscillation frequency of the VCO for the tuner based on this frequency difference using a PLL circuit. The frequency is quickly changed to tune in the optionally offset broadcast signal.