Arrangement for tuning the frequency of a reference oscillator in an FSK receiver

摘要

For tuning the reference frequency of an FSK receiver to the mid-frequency of the two signal frequencies, the signal to be demodulated is selected by the reference frequency by way of using a certain number of oscillations of the non-demodulated signal to fix a time window within which the oscillations of the reference oscillator are counted. The counting result is compared with a predetermined set value, and an error signal is derived from any deviation.