E4C01

What is the effect of excessive phase noise in the local oscillator section of a receiver?

  1. It can cause strong signals on nearby frequencies to interfere with reception of weak signals

E4C02

Which of the following is the result of the capture effect in an FM receiver?

  1. The strongest signal received is the only demodulated signal

E4C03

What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?

  1. Capture effect

E4C04

What is meant by the noise floor of a receiver?

  1. The equivalent input noise power when the antenna is replaced with a matched dummy load

E4C05

What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?

  1. The theoretical noise at the input of a perfect receiver at room temperature

E4C06

The thermal noise value of a receiver is -174 dBm/Hz. What is the theoretically best minimum detectable signal for a 400 Hz bandwidth receiver?

  1. -148 dBm

E4C07

What does the MDS of a receiver represent?

  1. The minimum discernible signal

E4C08

How might lowering the noise figure affect receiver performance?

  1. It would increase signal to noise ratio

E4C09

Which of the following is most likely to be the limiting condition for sensitivity in a modern communications receiver operating at 14 MHz?

  1. Atmospheric noise

E4C10

Which of the following is a desirable amount of selectivity for an amateur RTTY HF receiver?

  1. 300 Hz

E4C11

Which of the following is a desirable amount of selectivity for an amateur single-sideband phone receiver?

  1. 2.4 kHz

E4C12

What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?

  1. Undesired signals may be heard

E4C13

How does a narrow band roofing filter affect receiver performance?

  1. It improves dynamic range by keeping strong signals near the receive frequency out of the IF stages

E4C14

Which of these choices is a desirable amount of selectivity for an amateur VHF FM receiver?

  1. 15 kHz

E4C15

What is the primary source of noise that can be heard from an HF-band receiver with an antenna connected?

  1. Atmospheric noise

 

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