Instantaneous amplitude of a constant frequency sine wave?

1. What is the instantaneous value of a sine wave?
2. What type of signal does not have instantaneous change in its amplitude?

What is the instantaneous value of a sine wave?

The instantaneous values of a sinusoidal waveform is given as the “Instantaneous value = Maximum value x sin θ ” and this is generalized by the formula.

What type of signal does not have instantaneous change in its amplitude?

Phase signals (PSs) are the basic elements of phase or frequency modulation and this shows their importance. They are real signals with constant instantaneous amplitude. They are characterized by a canonical pair [1, ϕ(t)] or by a unique function ϕ(t) such that exp[jϕ(t)] is an AS.