Question

An amplitude modulated wave is represented by,

v_AM = 4 (1 + 0.2 sin 314 t) sin (314 × 10² t)

For this wave, one can say that 

(1) Frequency of the upper sideband is 5000 Hz; and frequency of the lower sideband is 50 Hz

(2) Frequency of the upper sideband is 100 Hz; and frequency of the lower sideband is 50 Hz 

(3) Frequency of the upper sideband is 5050 Hz; and frequency of the lower sideband is 4950 Hz 

(4) Frequency of the upper sideband is 314×10² Hz; and frequency of the lower sideband is 314 Hz.

Answer 1

Correct option: (3)

Explanation: 

According to the expression,

Therefore, 

Frequency of the upper sideband = f_c – f_m = 5050 Hz 

Frequency of the lower sideband = f_c – f_m = 4950 Hz