The noise blanker or noise limiter is used to suppress or reduce noise from motor ignition sparks or an electric fence.
In the simplest circuit only two anti-parallel diodes (two semiconductor diodes or two systems of a double diode tube) are used. In case of voltage peaks, one or the other diode becomes conductive and the disturbing crackle is suppressed.
Some semi-professional shortwave receivers from the amateur radio segment are equipped with more complex circuits to eliminate interference, especially the Russian over the horizon radar of the 1980s led to broadband interference pulses in the shortwave bands. It was also called the „Woody Woodpecker“.