Observation

     The expected answers were:

1. (a)    Define the following terms:
   i.   phase modulation;
   ii   frequency modulation.
    (b)     State the function of the following stages in the operation of a superheterodyne radio
   receiver;
   i.  mixer;
   ii. local oscillator;
   iii. detector.

   The expected answers were:

   1. Definition of Terms

   (i)      Phase modulation is the process of varying the instantaneous phase of a carrier signal in accordance with the magnitude of a modulating signal.        
   (ii)    Frequency modulation is the process in which the frequency of a carrier varies in accordance with the magnitude of a modulating signal.                           

   1. Functions of the following stages in a superheterodyne radio receiver
   2. Mixer stage: provides the IF signal from the mixing of the

   local oscillator (L.O.) and radio frequency (R.F.) signals.                             

   1. Local Oscillator:  generates a signal in which the frequency is above

   the incoming radio frequency signal.                                                                          

   1. Detector:  recovers the modulating signal from the modulated carrier signal or recovers the information signal from the modulated carrier signal. 

                      
   Question 6 required candidates to state the function of some stages in the operation of a superheterodyne radio receiver. Majority of the candidates, as reported, responded fairly well in this question.