Question

A signal wave of frequency $12kHz$ is modulated with a carrier wave of frequency $2.51MHz$. The upper and lower side band frequencies are respectively

• A. $2512$ $kHz$ and $2508$ $kHz$
• B. $2522$ $kHz$ and $2488$ $kHz$
• C. $2522$ $kHz$ and $2498$ $kHz$
• D. $2512$ $kHz$ and $2488$ $kHz$

Answer 1

Answer: (C)

Upper side band (USB) frequency $=f_c+f_m$
$=\left(2.51\right)MHz+\left(12\right)kHz=\left(2510+12\right)kHz=2522kHz$
Lower side band (LSB) frequency $=f_c-f_m$
$=\left(2.51\right)MHz-\left(12\right)kHz=\left(2510-12\right)kHz=2498kHz$