• Subject:


  • Topic:


(a) Define the term 'modulation index,' used in communication system. Why is

     its value kept less than or equal to one ?

(b) A message signal of frequency 10 kHz and peak voltage of 10V is used to

      modelate a carrier frequency 1 MHz and peak voltage 10 V. Determine the

      (i) modulation index, and 

      (ii) side bands produced.

                                                                                                      3 marks


a)     μ=AmAc                                                                                           1 marks         μ1 to avoid distortion of signal.                                              12 marks        


b)   μ=10V10V=1                                                                               12 marks       Vc-Vm = (1000-10)kHz=990kHz                                     12 marks                Vc+Vm=(1000+10)kHz=1010kHz                            12 marks