Question

An amplitude modulated wave is represented by the expression $v _{ m }=5(1+0.6 \cos 6280 t )$ $\sin \left(211 \times 10^{4} t \right)$ volts. The minimum and maximum amplitudes of the amplitude modulated wave are, respectively :

• A. $5 V , 8 V$
• B. $\frac{3}{2} V , 5 V$
• C. $\frac{5}{2} V , 8 V$
• D. $3 V , 5 V$

Answer 1

Answer: (C)

$\frac{5}{2} V , 8 V$

Answer 2

$V _{ m }=5(1+0.6 \cos 6280 t ) \sin \left(211 \times 10^{4} t \right)$
$V _{ m }=[5+3 \cos 6820 t ] \sin \left(211 \times 10^{4} t \right)$
$V _{\max }=5+3=8$
$V _{\text {min. }}=5-3=2$