Question

The audio signal voltage is given by $V_m=2sin12\pi \times {10}^{3}t$ . The bandwidth and LSB if carrier wave has a frequency $3.14\times {10}^{6}rad/s$

• A. 12 KHz; 494 KHz
• B. 6 KHz; 313 KHz
• C. 6 KHz; 494 KHz
• D. 18 KHz; 494 KHz

Answer 1

Answer: (A)

12 KHz; 494 KHz

Frequency of Audio Signal $=\frac{12\pi \times {10}^3}{2\pi }=6\times {10}^{3}Hz$

Frequency of Carrier wave $=\frac{\pi \times {10}^6}{2\pi }=500\times {10}^{3}Hz$

LSB $=f_C-f_A=(500-6)\times {10}^3=494Khz$

Bandwidth $=2f_A=12Khz$