Communication Systems - Engineering

Q1:

When Pc is the unmodulated carrier power and Pt is the total power in the modulated wave, then the maximum power in AM wave is

A Pt = 1.5 Pc

B Pt = 2.5 Pc

C
Pt = 2

D
Pt = 22 Pc

ANS:A - Pt = 1.5 Pc

In AM, Pt = Pc(1+ma^2/2); ma = modulation index (0 to 1).

Now Pt is maximum when ma is maximum (=1).

So, Pt(MAX) = Pc(1+1/2) = 3/2*Pc = 1.5 Pc. Option A is correct.