Calculate average power saving.

An AM broadcast station has modulation index which is 0-75 on the average. What would be its average power saving, if it could go over to single side band suppressed carrier transmissions, while having to maintain the same signal strength in its reception area.

Subject : Principle of Communication Engineering

Topic : Amplitude Modulation and Demodulation

Difficulty : High

1 Answer

The total transmitted power by a DSBFC system at m=0.75 is

**Pt = Pc[1+(0.75^2/2)] 

       = 1.281 Pc**

The total transmitted power by a SSB system at m=0.75 is

 **Pt = m^2 Pc / 4

       = 0.14 Pc**

% power saving = [(1.281Pc - 0.14 Pc)/ 1.281 Pc] * 100%

           = 89%
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