Noise suppression circuit for video signal - separates signal into high and low frequency components and has delay circuit with time delay when switched over

摘要

In the circuit a video signal is separated into its high and low frequency components by a separating circuit (3). The signal at an output (15) of a delay circuit (17) is combined with the separated low frequency signal in a combining circuit (11) whose output is applied to the input (19) of the delay circuit. The time delay of this circuit is switched from field to field by means of a change-over switch (53) so that this time delay changes from field-to-field to a field period minus and a field period plus half a line period. The noise-suppressed low frequency output from the combining circuit (11) is added to the separated high frequency component in an adder circuit (25). In use such a noise suppression circuit produces no travelling noise patterns on a television display.