Disclosed are a pulse cancellation system and a pulse cancellation method for enhancing the effect of a small pulse superimposed on a large pulse, in the context of processing video signals in a circuit employing a compression video amplifier. The original waveform is delayed by a selected interval which is short as compared with the expected duration of pulses of interest in it, and the delayed waveform is subtracted from the original one to cancel the effect of those portions of pulses which are longer than the selected delay interval. Excursions of the resulting waveform which are on a selected side of a selected baseline can be removed, if desired. Alternative embodiments provide for selectively bypassing the delay and cancellation circuits, to feed the detector output directly to the compression amplifier in some cases, and for placing the small pulse enhancing circuit before the detector.
In an RF receiver a system is provided to digitally determine when a pulse has stabilized and when a pulse has restabilized after becoming unstable. The restabilized levels can be detected whether they are above or below the initial stabilization level. The system uses the stable information to determine if a pulse-on-pulse signal is being received or if a trailing edge pulse is being received. The system can provide separate information about each pulse in a pulse-on-pulse situation and can provide separate information concerning the leading pulse and trailing pulse when the trailing pulse occurs in the shadow of the leading pulse.
