A signal m(t) = 20cos (2π200t) along with carrier generates an FM signal x(t) = 40cos {2π x 106t + 10 sin (2π 200t)}. What will be the value of approximate bandwidth of the frequency modulation? (Marks : 02)

a. 200 kHz

b. 2 kHz

c. 4.4 kHz

d. None of these

ANSWER: 4.4 kHz

Explanation:

Given data :

Frequency Deviation = Δf = 10 x ( 2π 200) rad

Deviation ratio = D = [10 x ( 2π 200)] / [( 2π 200)]

Therefore, D = 10

Bandwidth of Frequency Modulated Signal is given by,

B = 2 (D + 1) fm

= 2 (10 +1 ) x 200

= 2 (11) x 200

= 22 x 200

= 4400

= 4.4 kHz