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Radio Receivers problems

  • 1. In a broadcast superheterodynes receiver having no RF amplifier, the loaded Q of the antenna coupling circuit is 100. If the intermediate frequency is 455 kHz. In receivers operating upto the limit of shortwave broadcasting the local oscillator often used is

  • Options
  • A. Armstrong oscillator
  • B. Colpitts oscillator
  • C. Clapp oscillator
  • D. Ultra Audio oscillator
    • Discuss
  • 2. A communication channel with additive white Gaussian noise, has a bandwidth of 4 kHz and an SNR of 15. Its channel capacity is

  • Options
  • A. 1.6 kbps
  • B. 16 kbps
  • C. 32 kbps
  • D. 256 kbps
    • Discuss
  • 3. An arbitrary signal m (t) has zero average value and it is bandlimited to 3.2 kHz. It is sampled at the rate of 8 K samples/S. The samples are passed through an ideal bandpass filter with centre frequency of 32 kHz and bandwidth of 6.4 kHz. The output of band pass filter is

  • Options
  • A. AM-DSB signal with suppressed carrier
  • B. AM-DSB signal with carrier
  • C. AM-SSB signal with carrier
  • D. a sequence of exponentially decaying sine waves
    • Discuss
  • 4. Noise limiter is provided on AM receivers to

  • Options
  • A. reduce interfering noise due to ignition system
  • B. reduce noise due to electrical storms
  • C. reduce interference due to electrical machinery
  • D. all of the above
    • Discuss
  • 5. Double spotting in a receiver is due to

  • Options
  • A. poor sensitivity of RF amplifier
  • B. high gain of IF amplifier
  • C. inadequate image frequency rejection
  • D. all of the above
    • Discuss
  • 6. Selectivity varies with receiving frequency, frequency is raised.

  • Options
  • A. Somewhat better when the receiving frequency is raised
  • B. Somewhat better at intermediate frequency
  • C. Somewhat worse when the receiving frequency is lowered
  • D. Somewhat worse when the receiving frequency is raised
    • Discuss
  • 7. Which curve represents the fidelity curve of a standard receiver?
    Electronics and Communication Engineering Radio Receivers: Which curve represents the fidelity curve of a standard receiver?

  • Options
  • A. Curve A
  • B. Curve B
  • C. Curve C
  • D. Curve D
    • Discuss
  • 8. The passband of the tuned circuits of a radio receiver should be equal to

  • Options
  • A. 20 kHz
  • B. 455 kHz
  • C. 1455 kHz
  • D. more than 455 kHz
    • Discuss
  • 9. Which of the following circuit cannot be used to demodulate SSB?

  • Options
  • A. Phase discriminator
  • B. Produce detector
  • C. Balanced modulator
  • D. Beat frequency oscillator
    • Discuss
  • 10. When a superheterodyne receiver is tuned to 455 kHz, its local oscillator provides a mixer with the input at 1010 kHz. The image frequency is

  • Options
  • A. 555 kHz
  • B. 1010 kHz
  • C. 1465 kHz
  • D. 1920 kHz
    • Discuss

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