Signals and Systems - Engineering

Q1:

The power in the signal s(t) = 8 cos (20 p - p/2) + 4 sin (15 pt) is

A 40

B 41

C 42

D 82

ANS:A - 40

s(t) = 8 cos(20p - p/2)+4 sin(15 pt) is:

Let x1(t) = 8 cos(20p - p/2).

X2(t) = 4 sin(15 pt),

Let p1(t) and p2(t) be the powers of x1(t) & x2(t) respectively.

P1 (t) = A2/2 = 82/2 = 64/2 = 32.

P2 (t) = A2/2 = 42/2 = 16/2 = 8.

The average power P = P1+P2 = 32+8 = 40.