Frequency synthesizer tuning system for television receivers

A television tuning system employs a frequency synthesizer system for establishing the tuning of the receiver. A programmable frequency divider, controlled by a reversible counter, is connected between the output of a reference oscillator and a phase comparator to which the output of the local oscillator in the tuner also is applied. The phase comparator output provides a tuning voltage for controlling the tuning of the local oscillator. A logic circuit is coupled to sense predetermined relationships of signals from a picture carrier detector, a sound carrier detector, an AFT signal, and the presence of vertical synchronization signal components for changing the count in the reversible binary counter to adjust the programmable frequency divider to compensate for channel frequency offsets which may occur in excess of the pull-in range of the AFT circuit.