When a receiver has good blocking performance, this means that

Solution (By Examveda Team)

Blocking Performance in a Receiver:
Blocking performance refers to a receiver's ability to reject unwanted signals, often strong signals, that are close in frequency to the desired signal. A receiver with good blocking performance is less susceptible to interference from these strong, out-of-band signals.

Correct Answer: Option C
A receiver with good blocking performance is unaffected by AGC (Automatic Gain Control) derived from nearby transmissions. AGC automatically adjusts the receiver's gain to maintain a constant output level. If a strong interfering signal is present near the desired signal's frequency, it can saturate the receiver's AGC system. This causes the AGC to reduce the gain, thereby weakening not only the interfering signal but also the desired signal. A receiver with good blocking will effectively reject the interfering signal, preventing it from affecting the AGC and hence the desired signal's reception.

Why other options are incorrect:
Option A: Double spotting is a phenomenon where two signals appear at the output of the receiver, usually due to poor image frequency rejection or inadequate filtering. While good blocking can help mitigate some instances of double spotting, it's not the primary definition of good blocking.
Option B: Poor image frequency rejection is the opposite of good performance. Image frequency is a spurious signal that can be received along with the desired signal. Good blocking performance aims to prevent interference from strong signals, but this is different from good image rejection, which is a different type of interference source.
Option D: Detector burnout refers to the damage of the detector stage due to an extremely strong signal. While a very strong interfering signal could lead to burnout, it is more associated with the receiver's overall dynamic range, rather than its blocking performance, which deals with signals of comparable power to the desired signal but not necessarily causing damage.