To prevent overloading of the IF amplifier in a receiver, one should use

Solution (By Examveda Team)

IF Amplifier Overloading:
An Intermediate Frequency (IF) amplifier is a crucial part of a radio receiver. It amplifies the signal at a fixed intermediate frequency (IF) after it has been converted from the radio frequency (RF) by a mixer. Overloading occurs when the input signal to the IF amplifier is too strong, causing distortion and a reduction in the dynamic range of the receiver.

Correct Answer: B. Variable Sensitivity
Variable sensitivity controls the gain of the receiver's RF amplifier stage. By reducing the gain of the RF amplifier, a weaker signal is passed on to the mixer and subsequently to the IF amplifier. This prevents the IF amplifier from receiving an excessively strong signal, thus avoiding overloading. In essence, it attenuates the strong signals before they reach the IF stage.

Why other options are incorrect:
A. Squelch: A squelch circuit mutes the receiver's audio output when no signal is present or when the signal strength is below a certain threshold. While helpful for reducing background noise, it does not directly address IF amplifier overloading. It operates on the audio output, not the RF or IF stages.

C. Variable Selectivity: Variable selectivity adjusts the bandwidth of the IF amplifier. While important for rejecting unwanted signals and improving signal-to-noise ratio, it doesn't inherently prevent the amplifier from being overloaded by a strong signal within the passband. A narrow bandwidth might even *exacerbate* overloading if a strong signal falls within that narrow band.

D. Double Conversion: Double conversion uses two mixer stages and two IF amplifiers at different frequencies. This improves image rejection and reduces the susceptibility to interference, but it doesn't directly solve the problem of IF amplifier overloading. A strong signal could still overload either of the IF amplifiers in a double conversion system.