Question

The amplitude of a sine carrier signal with a peak value of 10V is modulated by another sine signal.If the modulation index of the resultant AM signal is0.4,then the maximum and minimum values of the envelope of the AM signal are respectively equal to by

Answer 1

Explanation:

Answer

Data given:

Frequency of carrier=f

c

=10MHz

frequency of the signal=f

s

=5KHz=0.005MHz

Amplitude of carrier signal=E

c

=10mV

Amplitude of audio signal=E

s

=6mV

solution

The modulated carrier wave contains the folloeing frequencies:

Original carrier wave of frequency=f

c

=10MHz

upper side band,f

c

+f

s

=10+0.005=10.005MHz

Lower side band frequency f

c

−f

s

=10−0.005=9.995MHz

The modulation factor μ=

A

c

A

m

=

10

6

=0.6

Amplitude =

2

μA

c

=3mV