Question

In amplitude modulation, the bandwidth is

• A. twice the audio signal frequency
• B. thrice the audio signal frequency
• C. thrice the carrier wave frequency
• D. twice the carrier wave frequency

Answer 1

Answer: (A)

twice the audio signal frequency

Answer 2

Modulation is a process of superposing a low frequency audio signals (called modulating signal) on a high frequency radio wave called carrier wave. Band width
$=({{f}_{c}}+{{f}_{m}})-({{f}_{c}}-{{f}_{m}})=2{{f}_{m}}$
Band width $=2\times$ audio signal frequency