Question

In amplitude modulation, the message signal $V_m\left(t\right)=1\sin (2\pi \times {10}^{5}t)$ volts and carrier signal $V_C\left(t\right)=20\sin (2\pi \times {10}^{7}t)$ volts. The modulated signal now contains the message signal with lower side band and upper side band frequency. Therefore the bandwidth of modulated signal is $\alpha \text{kHz}$. The value of $\alpha$ is :

• A. $0\text{kHz}$
• B. $50\text{kHz}$
• C. $200\text{kHz}$
• D. $100\text{kHz}$

Answer 1

The correct option is C $200\text{kHz}$

In amplitude modulation, band width,
$=2\times f_m=2\times \frac{{\omega }_m}{2\pi }$
$=2\times {10}^{5}Hz=200\text{kHz}$

Hence, $\left(A\right)$ is the correct answer.