Video clamping circuit
AssigneeAlps Electric Co., Ltd.
InventorAkiyuki Yoshisato
Life of this patent
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Abstract
A video clamping circuit adapted for satellite communication includes an operational amplifier for detecting the current flowing into a diode connected to the input terminal of the buffer amplifier of the circuit. The circuit further includes rectifying and smoothing elements for deriving a DC voltage from the output from the operational amplifier and adding the DC voltage to the signal of the output stage of the buffer amplifier in an anti-phase relation, so that an energy dispersal signal superimposed on a video signal is removed and waveform distortion is minimized.
Claims2
In a video clamping circuit for receiving a video signal on which an energy dispersal signal is superimposed, which includes a clamping buffer circuit having a buffer amplifier having an input section and an output section, and a clamping diode connected to the input section of the buffer amplifier,
- the improvement comprising:
- means for detecting the current flowing through the diode and producing a detection signal indicative of a variation in an input signal level at the input section of the buffer amplifier;
- means for producing a cancellation signal from said detection signal;
- and
- means for superimposing the cancellation signal on an output signal at the output section of the buffer amplifier in an anti-phase relation.
Dependencies are inferred from the claim text.