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US 5,179,321 AGranted
Centering circuit
AssigneeThomson Consumer Electronics, Inc.
InventorsLawrence E. Smith, James A. Wilber
Life of this patent
Estimating the term…
Abstract
Retrace pulses are integrated by an R-C network to produce a ramp signal. The resistive member of the R-C network is bypassed by a diode to provide rapid retrace at the conclusion of the ramp portion of the integrated signal. A voltage divider at the output of the integrator adjusts the DC level of the ramp signal without affecting the constant of integration of the R-C network.
Claims15
A video display apparatus for displaying a video signal comprising:
- means for deriving a signal from said video signal indicative of the horizontal timing of said video signal;
- means for deriving, by an integrating means, a signal from a horizontal flyback transformer, indicative of horizontal deflection timing;
- means for comparing said video indicative signal with said deflection indicative signal to produce a feedback signal which controls timing of a deflection current produced by said deflection generator;
- and
- means for adjusting the DC bias of the deflection indicative signal input to said comparing means without substantially affecting said integration, to control the relative timing of horizontal trace and the said video signal.
2 more elements
A synchronizing system, comprising:
- a deflection circuit for a video display, developing flyback pulses indicative of horizontal deflection;
- means for generating a deflection timing signal by integrating pulses indicative of said flyback pulses;
- means, operable independently of said means for generating said deflection timing signal, for phase adjusting said deflection timing signal relative to said deflection circuit;
- and
- a phase locked loop having a phase comparator for receiving a signal indicative of a synchronizing component in a video signal and said phase adjusted deflection timing signal, and having a controllable deflection oscillator responsive to said phase comparator for controlling said deflection circuit.
2 more elements
A synchronizing system, comprising:
- a deflection circuit for a video display, developing flyback pulses;
- means for generating substantially rectangular pulses responsive to said flyback pulses;
- means for integrating said rectangular pulses to generate a sawtooth waveform having ramp portions whose slope is determined by a constant of integration, at a predetermined DC bias level;
- means for adjusting said DC bias level, without disturbing said slope of said ramp portions of said sawtooth waveform;
- a phase comparator for receiving a signal indicative of a synchronizing component in a video signal and said DC bias level adjusted sawtooth waveform;
- and,
- a controllable oscillator responsive to said phase comparator for controlling said deflection circuit.
4 more elements
Dependencies are inferred from the claim text.