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In an amplitude modulator circuit, the carrier wave is given by, c(t) = 4 sin(20000 πt) while modulating signal is given by, m(t) = 2 sin(2000 πt). The values of modulation index and lower side band frequency are:
- 0.3 and 9 kHz
- 0.5 and 10 kHz
- 0.4 and 10 kHz
- 0.5 and 9 kHz
Correct answer: 0.5 and 9 kHz
Solution
The modulation index is calculated as the ratio of the peak amplitude of the modulating signal to the peak amplitude of the carrier wave, which in this case is 2/4 = 0.5. The lower sideband frequency is determined by subtracting the modulating frequency (1000 Hz) from the carrier frequency (10000 Hz), resulting in 9000 Hz or 9 kHz.
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