Question
How does a noise blanker work?
Answer Options
- A) By temporarily increasing received bandwidth
- B) By redirecting noise pulses into a filter capacitor
- C) By reducing receiver gain during a noise pulse
- D) By clipping noise peaks
Correct Answer: C
Explanation
A noise blanker is a circuit designed to eliminate or significantly reduce impulse noise, such as ignition noise from vehicles or power line static. Impulse noise typically consists of very short, high-amplitude bursts that quickly exceed the level of the desired signal.
The noise blanker works by detecting these sudden, sharp pulses and then quickly, temporarily reducing receiver gain during a noise pulse. Because the pulse is so short (often just microseconds), the blanking action is imperceptible to the listener, while the high-amplitude noise pulse is prevented from reaching the subsequent receiver stages.
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