FREQUENCY SYNTHESIZER TUNING SYSTEM FOR TELEVISION RECEIVERS

A television tuning system is provided which 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...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
1. Verfasser: SIDERIS, SOTIRIOS
Format: Patent
Sprache:eng ; fre
Schlagworte:
Online-Zugang:Volltext bestellen
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:A television tuning system is provided which 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 control ling 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. The novel system thus adjusts for frequency offsets of the received signal which would otherwise cause the station to be mistuned if a conventional frequency synthesizer tuning system were used.