In an amplitude modulator circuit, the carrier wave is given by, \(C(t) = 4\sin(20000\pi t)\) while modulating signal is given by, \(m(t) = 2\sin(2000\pi t)\). The values of modulation index and lower side band frequency are :
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- 0.3 and 9 kHz
- 0.5 and 10 kHz
- 0.4 and 10 kHz
- 0.5 and 9 kHz
The Correct Option is D
Solution and Explanation
Signal: \(A_m = 2\), \(\omega_m = 2000\pi\Rightarrow f_m = 1000\ \mathrm{Hz} = 1\ \mathrm{kHz}\).
Modulation index \(\mu = A_m/A_c = 2/4 = 0.5\).
Lower side band frequency \(= f_c - f_m = 10 - 1 = 9\ \mathrm{kHz}\).
Answer: (4) 0.5 and 9 kHz
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