A message signal of 12 kHz and peak voltage 20 V is used to modulate a carrier wave of frequency 12 MHz and peak voltage 30 V. Calculate the (i) modulation index (ii) side- band frequencies.

Answer

0.67 ; 12.012 MHz ; 11.988MHz.

Explanation

Here, `v_m = 12kHz = 0.012 MHz, A_m = 20 V`.
`v_C = 12 MHz, A_C = 30 V`
`mu_a = A_m/A_c = 20/30 = 0.67`
USB = `v_c + v_m = (12 + 0.012)MHz`
`= 12.012 MHz`
LSB `= v_c -v_m = (12 - 0.012)MHz`
`= 11.988 MHz`.