E4D01

What is meant by the blocking dynamic range of a receiver?

  1. The difference in dB between the level of an incoming signal which will cause 1 dB of gain compression, and the level of the noise floor

E4D02

Which of the following describes two types of problems caused by poor dynamic range in a communications receiver?

  1. Cross modulation of the desired signal and desensitization from strong adjacent signals

E4D03

How can intermodulation interference between two repeaters occur?

  1. When the repeaters are in close proximity and the signals mix in one or both transmitter final amplifiers

E4D04

What is an effective way to reduce or eliminate intermodulation interference between two repeater transmitters operating in close proximity to one another?

  1. By installing a properly terminated circulator at the output of the transmitter

E4D05

If a receiver tuned to 146.70 MHz receives an intermodulation-product signal whenever a nearby transmitter transmits on 146.52 MHz, what are the two most likely frequencies for the other interfering signal?

  1. 146.34 MHz and 146.61 MHz

E4D06

If the signals of two transmitters mix together in one or both of their final amplifiers, and unwanted signals at the sum and difference frequencies of the original signals are generated, what is this called?

  1. Intermodulation interference

E4D07

Which of the following describes the most significant effect of an off-frequency signal when it is causing cross-modulation interference to a desired signal?

  1. The off-frequency unwanted signal is heard in addition to the desired signal

E4D08

What causes intermodulation in an electronic circuit?

  1. Nonlinear circuits or devices

E4D09

What is the purpose of the preselector in a communications receiver?

  1. To improve rejection of unwanted signals

E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

  1. A pair of 40 dBm signals will theoretically generate the same output on the third order intermodulation frequency as on the input frequency

E4D11

Why are third-order intermodulation products within a receiver of particular interest compared to other products?

  1. The third-order product of two signals which are in the band is itself likely to be within the band

E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

  1. Desensitization

E4D13

Which of the following can cause receiver desensitization?

  1. Strong adjacent-channel signals

E4D14

Which of the following is a way to reduce the likelihood of receiver desensitization?

  1. Decrease the RF bandwidth of the receiver

 

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