Variable peaking control circuit
AssigneeRCA Corporation
InventorFrank C. Liu
Life of this patent
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Abstract
A video signal processing circuit including signal substitution circuitry for eliminating impulse noise has a signal peaking circuit conditionally operable for the duration of one or more video fields depending upon the presence of noise being detected in the vertical blanking interval. A circuit responsive to enabling pulses generated as a result of impulse noise or defects being detected in a vertical blanking interval provides one of two peaking control signals for controlling the level of peaking applied to the video signal by the peaking circuit.
Claims7
A circuit combination for processing a composite video signal, comprising:
- a video signal peaking circuit responsive to said composite video signal and having a peaking control signal input terminal for applying a peaking control signal to control the degree of peaking;
- first circuit means responsive to the unpeaked composite video signal for detecting impulse noise above a threshold level in blanking intervals of said composite video signal and for generating a further control signal having a duration of at least a video field period whenever said impulse noise is detected;
- a first source of peaking control signal;
- a second source of peaking control signal;
- and
- second circuit means responsive to said further control signal for selectively coupling said first source of peaking control signal to said control input terminal for a duration of at least one video field period and responsive to the absence of said further control signal for coupling said second source of peaking signal to said control input terminal.
Video signal processing circuitry comprising:
- defect substitution circuitry for replacing defective video signal segments with video signal segments advanced or delayed in time therefrom;
- defect detection circuitry responsive to defects in said video signal for generating a switching signal to control said defect substitution circuitry;
- a video signal peaking circuit having an input terminal connected to an output terminal of said substitution circuitry, and having a peaking control input terminal, said peaking circuit being responsive to a peaking control signal for establishing the degree of peaking applied to the video signal;
- first circuit means responsive to said switching signal and to video signal blanking signals for generating a further control signal when signal defects are detected during a blanking interval of said video signal, and wherein said further control signal is of at least one video field duration;
- a first and second source of peaking control signal;
- and
- second circuit means responsive to said further control signal for coupling said first source of peaking control signal to said peaking control input terminal for at least one video field period, and for coupling said second source of peaking control signal to said peaking control input terminal in the absence of said further control signal.
Dependencies are inferred from the claim text.