Question
What undesirable effect can occur when using a noise blanker?
Answer Options
- A) Received audio in the speech range might have an echo effect
- B) The audio frequency bandwidth of the received signal might be compressed
- C) Strong signals may be distorted and appear to cause spurious emissions
- D) FM signals can no longer be demodulated
Correct Answer: C
Explanation
A noise blanker works by rapidly turning off the receiver’s IF amplifier stage during the extremely short duration of an impulse noise event. While effective against things like ignition noise, this rapid switching can also introduce undesirable effects, especially when combined with powerful signals.
The most common undesirable effect is that strong signals may be distorted and appear to cause spurious emissions. When a strong signal is present, the fast ON/OFF switching of the blanker circuit can generate wideband, impulse-like distortion that can make the strong signal sound ‘dirty’ or ‘splattery’ and introduce wideband noise that mimics spurious emissions.
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