waecE-LEARNING
Electronics Paper 2, May/June 2013  
Questions: 1 2 3 4 5, 6 &7 8 9 10 Main
General Comments
Weakness/Remedies
Strength
















Question 4
  1.  In a colour T.V. receiver, state the function of the following:
    1. r.f. tuner;
    2. video amplifier;
    3. video detector;
    4. sync. separator.
  2.  State the type of modulation used in television for the following:
  1. video;
  2. sound.

 

           

_____________________________________________________________________________________________________
OBSERVATION

     The expected answers were:

  1.  (i)     r.f. tuner – selects desired station;

               ii. video amplifier – amplifies video signal;

  1. video detector – detects (or modulates) the amplitude modulated picture carrier;
  2. sync. separator – separates the synch pulse from the composite video signal.
  1.  Types of modulation
    1. Video – amplitude modulation (a.m.)
    2. Sound – frequency modulation (f.m.)

         
The question was on Communication System. It was unpopular with the candidates. The performance of the candidates was average.

Powered by Sidmach Technologies(Nigeria) Limited .
Copyright © 2015 The West African Examinations Council. All rights reserved.