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Electronics Paper 2, Nov/Dec. 2008  
Questions: 1 2 3 4 5 6 7 Main
General Comments
Weakness/Remedies
Strength









Question 4

(a)        Explain the following terms in relation to a receiver:
            (i)         selectivity;

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            (ii)        sensitivity.

(b)        State three advantages of the superheterodyne receiver over the tuned-radio
            frequency receiver.

(c)        State one disadvantage of the superheterodyne receiver.

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OBSERVATION

The expected answers were:

(a) (i)    Selectivity, for a radio receiver, is a measure of  the ability of the receiver to  
                 distinguish between adjacent channels, and consequently tune to a desired
     channel without attracting interference from the adjacent channels.

(ii) Sensitivity, measures the extent to which the receiver is able to pick and       
      process weak signals in the presence of background noise.

 (b)       Any three advantages
            -           Better selectivity
            -           Higher sensitivity
            -           Higher gain
            -           Better efficiency

(c)        Any one advantage
            -           Higher costs
            -           More complex electronic circuitry.

This question was on communication systems, very few candidates attempted it.

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