By redirecting noise pulses into a filter capacitor
By reducing receiver gain during a noise pulse✓Bonne réponse
By clipping noise peaks
Explication
Impulse noise such as ignition noise consists of very short high-amplitude bursts, so a noise blanker detects each pulse in a wide-bandwidth auxiliary channel and momentarily reduces receiver gain for its duration. The wanted signal is interrupted only for microseconds, which is inaudible, while the pulse is removed.