Question:
in an amplitude modulator circuit, the carrier wave is given by, $\mathrm{C}(t)=4 \sin (20000 \pi t)$ while modulating signal is given by, $m(t)=2 \sin (2000 \pi t)$. The values of modulation index and lower side band frequency are :
Correct Option: , 4
Solution:
(4) Modulation index, $\mu=\frac{A_{m}}{A_{c}}=\frac{2}{4}=0.5$
Given, $f_{e}=\frac{20000 \pi}{2 \pi}=10000 \mathrm{~Hz}$.
and $f_{m}=\frac{2000 \pi}{2 \pi}=1000 \mathrm{~Hz}$.
$\therefore \quad L S B=f_{e}-f_{m}=10000-1000=9000 \mathrm{~Hz}$.