Question

In the equation x(t) = a(t)cos[2πFct+θ(t)], Which of the following relations between a(t) and x(t), θ(t) and x(t) are true?

(a) a(t), θ(t) are called the Phases of x(t)

(b) a(t) is the Phase of x(t), θ(t) is called the Envelope of x(t)

(c) a(t) is the Envelope of x(t), θ(t) is called the Phase of x(t)

(d) none of the mentioned

This question was addressed to me in examination.

My question is taken from The Representation of Bandpass Signals in division Sampling and Reconstruction of Signals of Digital Signal Processing

Answer 1

The correct answer is (c) a(t) is the Envelope of x(t), θ(t) is called the Phase of x(t)

The explanation: In the equation x(t) = a(t) cos[2πFct+θ(t)], the signal a(t) is called the Envelope of x(t), and θ(t) is called the phase of x(t).