Question

A sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of $120 \, V$ and $80\, V$ respectively. The amplitude of each sideband is :

• A. $10\, V$
• B. $5 \, V$
• C. $20 \, V$
• D. $15 \, V$

Answer 1

Answer: (A)

$ A _{ c }+ A _{ m }=120 $
$A_c-A_m=80 $
$ \therefore \overline{ A _{ c }}=100 $
$ A_m=20 $
Modulation index $=\frac{20}{100}=\frac{1}{5} $
Amplitude of each sideband
$ = A _{ c } \frac{(\text { mod ulation index })}{2} $
$ =100 \times \frac{1}{10}=10 volt $