5.4 KiB
5.4 KiB
E4D Receiver performance characteristics: dynamic range; intermodulation and cross-modulation interference; third-order intercept; desensitization; preselector; sensitivity; link margin
- E4D01 (A)
What is meant by the blocking dynamic range of a receiver? #card
- A. The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression
- B. The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other
- C. The difference in dB between the noise floor and the third-order intercept point
- D. The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
- E4D02 (A)
Which of the following describes problems caused by poor dynamic range in a receiver? #card
- A. Spurious signals caused by cross modulation and desensitization from strong adjacent signals
- B. Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband
- C. Poor weak signal reception caused by insufficient local oscillator injection
- D. Oscillator instability and severe audio distortion of all but the strongest received signals
- E4D03 (B) What creates intermodulation interference between two repeaters in close proximity? #card
- E4D04 (B) Which of the following is used to reduce or eliminate intermodulation interference in a repeater caused by a nearby transmitter? #card
- E4D05 (A) What transmitter frequencies would create an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz? #card
- E4D06 (C) What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency? #card
- E4D07 (A) Which of the following reduces the likelihood of receiver desensitization? #card
- E4D08 (C) What causes intermodulation in an electronic circuit? #card
- E4D09 (C) What is the purpose of the preselector in a communications receiver? #card
- E4D10 (C)
What does a third-order intercept level of 40 dBm mean with respect to receiver performance? #card
- A. Signals less than 40 dBm will not generate audible third-order intermodulation products
- B. The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
- C. A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
- D. A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
- E4D11 (A)
Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products? #card
- A. Odd-order products of two signals in the band being received are also likely to be within the band
- B. Odd-order products are more likely to overload the IF filters
- C. Odd-order products are an indication of poor image rejection
- D. Odd-order intermodulation produces three products for every input signal within the band of interest
- E4D12 (C) What is the link margin in a system with a transmit power level of 10 W (+40 dBm), a system antenna gain of 10 dBi, a cable loss of 3 dB, a path loss of 136 dB, a receiver minimum discernable signal of -103 dBm, and a required signal-to-noise ratio of 6 dB? #card
- E4D13 (A) What is the received signal level with a transmit power of 10 W (+40 dBm), a transmit antenna gain of 6 dBi, a receive antenna gain of 3 dBi, and a path loss of 100 dB? #card
- E4D14 (D) What power level does a receiver minimum discernible signal of -100 dBm represent? #card