JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Semiconductors

A message signal of frequency 5 kHz is used to modulate a carrier signal of frequency 2 MHz. The bandwidth for amplitude modulation is:

Answer: (C)

Solution

An amplitude-modulated signal carries side bands at

f_{c} + f_{m}

and

f_{c} - f_{m}

, so the band it occupies is

(f_{c} + f_{m}) - (f_{c} - f_{m}) = 2 f_{m}

, independent of the carrier. With

f_{m} = 5 kHz

the bandwidth is

2 \times 5 = 10 kHz

JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Single correct option