Question
What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?
Answer Options
- A) Reciprocal mixing
- B) Quieting
- C) Desensitization
- D) Cross modulation interference
Correct Answer: C
Explanation
A strong signal on a frequency close to the desired receiving frequency can cause a receiver’s front-end or IF amplifier stages to operate outside of their linear range. This over-driving of the stages leads to a significant loss of performance, specifically the ability to hear weaker signals.
This phenomenon is called Desensitization (or ‘desense’). It occurs when the strong, unwanted signal saturates the receiver’s early stages, effectively reducing the gain of the desired signal and increasing the noise floor, thereby reducing the receiver’s overall sensitivity to weak signals and limiting the operator’s ability to complete a contact.
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