Numerical - Depth of Modulation/ Modulation Index

Calculate the depth of modulation when a transmitter radiates a signal of 9.8KW after modulation and 8KW without modulation of the signal.

a.) 80%
b.) 67%
c.) 50%
d.) 100%

Correct Answer: 67%


Ptotal = 9.8KW

Pc = 8KW

Power of the signal (Ptotal) transmitted by a transmitter after modulation is given by

Ptotal = Pc (1+ m2/2)

Where Pc is the power of carrier i.e., without modulation

M is the modulation index

9.8= 8(1+ m2/2)
9.8/8=1+ m2/2
m=0.67 = 67%
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