Wide band automatic frequency control circuit
AssigneeGTE Sylvania Incorporated
InventorsRangaswamy Arumugham, William Frank Kruszewski, Karol Siwko
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Abstract
An automatic frequency control (AFC) circuit for a signal receiver having a tuner, intermediate frequency (IF) amplifier, video amplifier, and sync pulse separation means includes a discriminator coupled to the IF stage and a signal combining means coupled to the discriminator means and sync pulse separation means and to the tuner to effect a given "pull-in" range for the tuner in response to error signals from the discriminator and an increased "pull-in" range upon loss of sync signals from the sync pulse separation means when the tuner stage is increasingly detuned.
Claims9
In a television receiver having an intermediate frequency (IF) amplifier stage coupled to a tuner stage and by a detector stage to a video amplifier stage connected to a cathode ray tube, an automatic frequency control (AFC) circuit comprising:
- discriminator means coupled to said IF amplifier stage for providing an error signal in response to signals deviating from the tuned frequency of said discriminator means;
- means coupled to said video amplifier stage for detecting sync pulses;
- and
- signal combining means coupling said discriminator means and said means for detecting sync pulses to said tuner stage for effecting a given "pull-in" range of said tuner stage in response to error signals from said discriminator means and an increased "pull-in" range in response to a signal from said means for detecting sync pulses indicative of the absence of detected sync pulses.
An automatic frequency control (AFC) circuit for a signal receiver having an intermediate frequency (IF) amplifier stage coupling a tuner stage to a detector stage with a video amplifier stage coupling the detector stage to a cathode ray tube and to a sync pulse separation means comprising:
- discriminator means coupled to said IF amplifier stage and including a bias development means;
- means coupled to said video amplifier stage for detecting sync pulses;
- and
- signal combining means coupled to said discriminator means, to said means for detecting sync pulses, and to said tuner stage for coupling of an error signal from said discriminator means to said tuner stage to cause alteration in tuning frequency with a given "pull-in" range of said tuner stage and an increase of said "pull-in" range upon a loss of a signal from said means for detecting sync pulses.
Dependencies are inferred from the claim text.