Question

Which among the following is the drawback of Pulse Position Modulation (PPM)?

(a) Synchronization is required between receiver and transmitter

(b) Synchronization is not required between receiver and transmitter

(c) Amplitude is constant

(d) Instantaneous power of PPM modulated signals is constant

I had been asked this question by my college director while I was bunking the class.

This question is from Coherent Detection of DSBSC Waves topic in section Double Sideband Suppressed Carrier Modulation of Analog Communications

Answer 1

The correct option is (a) Synchronization is required between receiver and transmitter

The explanation: Pulse Position Modulation (PPM) is a type of modulation process in which  position of the pulse of the carrier wave is varied with respect to the instantaneous position values of the message signal. In PPM, there is minimum noise interference but the main disadvantage of the PPM modulation technique is that synchronization between transmitter and receiver must be needed.