E4C-2012: Receiver performance characteristics, phase noise, capture effect, noise floor, image rejection, MDS, signal-to-noise-ratio; selectivity
What is an effect of excessive phase noise in the local oscillator section of a receiver?
It can cause strong signals on nearby frequencies to interfere with reception of weak signals
It limits the receiver's ability to receive strong signals
It reduces receiver sensitivity
It decreases receiver third-order intermodulation distortion dynamic range
Which of the following portions of a receiver can be effective in eliminating image signal interference?
A front-end filter or pre-selector
A narrow IF filter
A notch filter
A properly adjusted product detector
What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?
What is the definition of the noise figure of a receiver?
The ratio in dB of the noise generated by the receiver compared to the theoretical minimum noise
The ratio of atmospheric noise to phase noise
The noise bandwidth in Hertz compared to the theoretical bandwidth of a resistive network
The ratio of thermal noise to atmospheric noise
What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?
The theoretical noise at the input of a perfect receiver at room temperature
The minimum detectable signal as a function of receive frequency
The noise figure of a 1 Hz bandwidth receiver
The galactic noise contribution to minimum detectable signal
A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?
What does the MDS of a receiver represent?
The minimum discernible signal
The meter display sensitivity
The multiplex distortion stability
The maximum detectable spectrum
How might lowering the noise figure affect receiver performance?
It would improve weak signal sensitivity
It would reduce the signal to noise ratio
It would reduce bandwidth
It would increase bandwidth
Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a conventional HF or VHF communications receiver?
Easier for front-end circuitry to eliminate image responses
Fewer components in the receiver
Improved receiver noise figure
Which of the following is a desirable amount of selectivity for an amateur RTTY HF receiver?
Which of the following is a desirable amount of selectivity for an amateur SSB phone receiver?
What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?
Undesired signals may be heard
How does a narrow-band roofing filter affect receiver performance?
It improves dynamic range by attenuating strong signals near the receive frequency
It improves sensitivity by reducing front end noise
It improves intelligibility by using low Q circuitry to reduce ringing
All of these choices are correct
On which of the following frequencies might a signal be transmitting which is generating a spurious image signal in a receiver tuned to 14.300 MHz and which uses a 455 kHz IF frequency?
What is the primary source of noise that can be heard from an HF receiver with an antenna connected?
Induction motor noise
Receiver front-end noise
● = Unseen
● = Weak
● = Review
● = Learned
● = Incorrect answer