Alternating Current Question 9
Question 9 - 30 January - Shift 1
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 :
(1) $15 V$
(2) $10 V$
(3) $20 V$
(4) $5 V$
Show Answer
Answer: (2)
Solution:
Formula: Modulation Index
$A_c+A_m=120$
$A_c-A_m=80$
$\therefore A_c=100$
$A_m=20$
Modulation index $=\frac{20}{100}=\frac{1}{5}$
Amplitude of each sideband
$=A_c$
(modulation index)
2
$=100 \times \frac{1}{10}=10$ volt
