Radio Receivers(Engineering > Electrical Engineering ) Questions and Answers

Question 1. A low ratio of the ac to the dc load impedance of a diode detector results in
  1.    Diagonal clipping
  2.    Poor AGC operation
  3.    Negative-peak clipping
  4.    Poor AF response
Explanation:-
Answer: Option C. -> Negative-peak clipping
Question 2. Indicate which of the following circuits could not demodulate SSB:
  1.    Balance modulator
  2.    Product modulator
  3.    BFO
  4.    Phase discriminator
Explanation:-
Answer: Option D. -> Phase discriminator
Question 3. If the intermediate frequency is very high (indicate false statement)
  1.    Image frequency rejection is very good
  2.    The local oscillator need not be extremely stable
  3.    The selectivity will be poor
  4.    Tracking will be improved
Explanation:-
Answer: Option D. -> Tracking will be improved
Question 4. One of the following cannot be used to demodulate SSB:
  1.    Product detector
  2.    Diode Balance modulator
  3.    Bipolar transistor balanced modulator
  4.    Complete phase-shift generator
Explanation:-
Answer: Option C. -> Bipolar transistor balanced modulator
Question 5. Indicate which of the following statements about the advantages of the phase discriminator over the slope detector is false:
  1.    Much easier alignment
  2.    Better linearity
  3.    Greater limiting
  4.    Fewer tuned circuits
Explanation:-
Answer: Option C. -> Greater limiting
Question 6. The controlled oscillator synthesizer is sometimes preferred over the direct one because
  1.    It is a simpler piece of equipment
  2.    Its frequency stability is better
  3.    It does not require crystal oscillator
  4.    It is relatively free of spurious frequency
Explanation:-
Answer: Option D. -> It is relatively free of spurious frequency
Question 7. A superheterodyne receiver with an IF of 450 kHz is tuned to a signal at 1200 kHz. The image frequency is
  1.    750 kHz
  2.    900 kHz
  3.    1650 kHz
  4.    2100 kHz
Explanation:-
Answer: Option D. -> 2100 kHz
Question 8. The local oscillator of a broadcast receiver is tuned to a frequency higher than the incoming frequency
  1.    To help the image frequency rejection
  2.    To permit easier tracking
  3.    Because otherwise an intermediate frequency could not be produced
  4.    To allow adequate frequency coverage without switching
Explanation:-
Answer: Option D. -> To allow adequate frequency coverage without switching
Question 9. Show which of the following statements about the amplitude limiter is untrue:
  1.    The circuit is always biased in class C, by virtue of the leak-type bias.
  2.    When the input increases past the threshold of the limiting, the gain decreases to keep the output constant.
  3.    The output must be tuned
  4.    Leak-type bias must be used
Explanation:-
Answer: Option A. -> The circuit is always biased in class C, by virtue of the leak-type bias.
Question 10. A receiver has poor IF selectivity. It will therefore also have poor
  1.    Blocking
  2.    Double-spotting
  3.    Diversion reception
  4.    Sensitivity
Explanation:-
Answer: Option A. -> Blocking
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