Variable speed horizontal automatic phase control
AssigneeZenith Radio Corporation
InventorJudson A. Hofmann
Life of this patent
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Abstract
A television receiver includes conventional circuitry for receiving processing and detecting an information bearing signal. Vertical scansion means respond to recovered synchronizing information and provide vertical scansion of a conventional cathode ray tube. A horizontal oscillator coupled to an output amplifier and high voltage generator generates a scansion signal and provides horizontal scansion of the cathode ray tube. An automatic phase control loop (APC) includes a differential amplifier phase detector which responds to the reference sync pulses and the horizontal output signal to produce an error voltage which is stored in a hold capacitor. A speed control amplifier coupled to the receiver AGC system varies the amount of phase detector action directly with signal strength to vary system speed.
Claims6
In a television receiver including signal means recovering picture, audio and scansion synchronizing information from a received signal;
- display means;
- automatic gain control means maintaining the recovered picture information at a substantially constant level, horizontal and vertical scansion means developing a raster on said display means and horizontal scansion synchronization means synchronizing the horizontal scansion of said display with said synchronizing information, the improvement comprising:
- control means producing analog variation of the system response speed of said horizontal scansion synchronization means directly with the amplitude of said received signal.
In a television receiver including signal means recovering picture, audio and scansion synchronizing information from a received signal;
- display means;
- automatic gain control means maintaining the recovered picture information at a substantially constant level, horizontal and vertical scansion means developing a raster on said display means and horizontal scansion synchronization means, including a local oscillator and phase discriminator, synchronizing the horizontal scansion of said display with said synchronizing information, the improvement comprising:
- control means varying the system response speed of said horizontal scansion synchronization means directly with the amplitude of said received signal by varying the error signal generating capability of said phase discriminator in response to said automatic gain control means.
Dependencies are inferred from the claim text.