What is the result of tuning an FM receiver above or below a signal's frequency?

• A. Loss of receiver sensitivity
• B. Distortion of the signal's audio gain
• C. Amplification of the signal
• D. Reduction of background noise

Answer: (B)

When tuning an FM receiver above or below a signal's frequency, the result is primarily a loss of receiver sensitivity rather than distortion of the signal's audio gain. FM receivers are designed to work best when they are precisely tuned to the carrier frequency of a transmitted signal.

When the receiver is tuned too far away from the correct frequency, it cannot effectively demodulate the signal. This is because FM demodulation relies on precise frequency tracking, and if the tuning is off, the receiver will struggle to lock onto the incoming signal. Consequently, this leads to a decrease in sensitivity, meaning the receiver's ability to pick up the signal weakens significantly.

The other options can be addressed in this context: distortion of the signal's audio gain typically pertains to issues within the demodulation process itself, but it is not the primary result of mis-tuning. Amplification of the signal does not occur; rather, the aim is to maintain a clear and strong reception of the signal when properly tuned. Furthermore, tuning away from the correct frequency does not reduce background noise; in fact, it can often increase the relative noise level, making it harder to discern the intended signal.

Thus, the essence of tuning an FM receiver incorrectly lies in its loss