Question

An audio signal of $25sin2$$\pi$ ($1400t$) amplitude modulates to $80sin2$$\pi$ $\left({10}^5\right)t$. The two sideband frequencies are:

• A. $98.6$ $kHz$, $101.4$ $kHz$
• B. $92.5$ $kHz$, $105.5$ $kHz$
• C. $94$ $kHz$, $102.5$ $kHz$
• D. $96$ $kHz$, $106$ $kHz$

Answer 1

Answer: (A)

$98.6$ $kHz$, $101.4$ $kHz$

$f_1=1400$
$f_2={10}^5$
Sidebands are defined as $f_2-f_1$ and $f_1+f_2$
Hence, sidebands are $98600Hz,101400Hz$, i.e., $98.6KHz,101.4KHz$.