Question

An amplitude modulated wave is represented by :
$C_m\left(t\right)=10(1+0.2\cos 12560t)\sin (111\times {10}^{4}t)$ volts. The modulating frequency in kHz will be

• A. 2000
• B. 1999
• C. 2000.0
• D. 1999.0

Answer 1

Answer: (A), (B), (C), (D)

Given :-
$C_m\left(t\right)=10(1+0.2\cos 12560t)\sin (111\times {10}^{4}t)$
Here,
${\omega }_m=12560=2\pi f_m$
$\Rightarrow f_m=\frac{12560}{2\pi }$
$\Rightarrow f_m\approx 2000\text{Hz}$