Question

Square Law modulators are ________

(a) used for frequency modulation

(b) used for pulse width modulation

(c) used for amplitude modulation

(d) used for phase modulation

This question was addressed to me at a job interview.

My question is taken from Transmitter topic in section Elements of Communication System of Analog Communications

Answer 1

The correct choice is (c) used for amplitude modulation

Best explanation: Square Law modulators are generally used for the generation of amplitude modulated signals. They have nonlinear current-voltage characteristics, such that output current or voltage varies as a square of the input.