Sampling and Reconstruction of Signals on Digital Signal Processing related Questions and Answers

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? 1. a(t), θ(t) are called the Phases of x(t) 2. a(t) is the Phase of x(t), θ(t) is called the Envelope of x(t) 3. a(t) is the Envelope of x(t), θ(t) is called the Phase of x(t) 4. None of the mentioned Answer :   3 - a(t) is the Envelope of x(t), θ(t) is called the Phase of x(t)