WorksheetsHam Radio Extra Questions Till 2020 Set E4C
Total questions: 17
Worksheet time: 17mins
Name
Class
Date
1.
E4C01 What is an effect of excessive phase noise in the local oscillator section of a receiver?
a)
A. It limits the receiver’s ability to receive strong signals
b)
B. It reduces receiver sensitivity
c)
C. It decreases receiver third-order intermodulation distortion dynamic range
d)
D. It can cause strong signals on nearby frequencies to interfere with reception of weak signals
2.
E4C02 Which of the following portions of a receiver can be effective in eliminating image signal interference?
a)
A. A front-end filter or pre-selector
b)
B. A narrow IF filter
c)
C. A notch filter
d)
D. A properly adjusted product detector
3.
E4C03 What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?
a)
A. Desensitization
b)
B. Cross-modulation interference
c)
C. Capture effect
d)
D. Frequency discrimination
4.
E4C04 How is the noise figure of a receiver defined?
a)
A. The ratio of atmospheric noise to phase noise
b)
B. The ratio of the noise bandwidth in Hertz to the theoretical bandwidth of a resistive network
c)
C. The ratio of thermal noise to atmospheric noise
d)
D. The ratio in dB of the noise generated by the receiver to the theoretical minimum noise
5.
E4C05 What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?
a)
A. The minimum detectable signal as a function of receive frequency
b)
B. The theoretical noise at the input of a perfect receiver at room temperature
c)
C. The noise figure of a 1 Hz bandwidth receiver
d)
D. The galactic noise contribution to minimum detectable signal
6.
E4C06 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?
a)
A. -174 dBm
b)
B. -164 dBm
c)
C. -155 dBm
d)
D. -148 dBm
7.
E4C07 What does the MDS of a receiver represent?
a)
A. The meter display sensitivity
b)
B. The minimum discernible signal
c)
C. The multiplex distortion stability
d)
D. The maximum detectable spectrum
8.
E4C08 An SDR receiver is overloaded when input signals exceed what level?
a)
A. One-half the maximum sample rate
b)
B. One-half the maximum sampling buffer size
c)
C. The maximum count value of the analog-to-digital converter
d)
D. The reference voltage of the analog-to-digital converter
9.
E4C09 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?
a)
A. Fewer components in the receiver
b)
B. Reduced drift
c)
C. Easier for front-end circuitry to eliminate image responses
d)
D. Improved receiver noise figure
10.
E4C10 Which of the following is a desirable amount of selectivity for an amateur RTTY HF receiver?
a)
A. 100 Hz
b)
B. 300 Hz
c)
C. 6000 Hz
d)
D. 2400 Hz
11.
E4C11 Which of the following is a desirable amount of selectivity for an amateur SSB phone receiver?
a)
A. 1 kHz
b)
B. 2.4 kHz
c)
C. 4.2 kHz
d)
D. 4.8 kHz
12.
E4C12 What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?
a)
A. Output-offset overshoot
b)
B. Filter ringing
c)
C. Thermal-noise distortion
d)
D. Undesired signals may be heard
13.
E4C13 How does a narrow-band roofing filter affect receiver performance?
a)
A. It improves sensitivity by reducing front end noise
b)
B. It improves intelligibility by using low Q circuitry to reduce ringing
c)
C. It improves dynamic range by attenuating strong signals near the receive frequency
d)
D. All of these choices are correct
14.
E4C14 What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and which uses a 455 kHz IF frequency?
a)
A. 13.845 MHz
b)
B. 14.755 MHz
c)
C. 14.445 MHz
d)
D. 15.210 MHz
15.
E4C15 What is usually the primary source of noise that is heard from an HF receiver with an antenna connected?
a)
A. Detector noise
b)
B. Induction motor noise
c)
C. Receiver front-end noise
d)
D. Atmospheric noise
16.
E4C16 Which of the following is caused by missing codes in an SDR receiver’s analog-to-digital converter?
a)
A. Distortion
b)
B. Overload
c)
C. Loss of sensitivity
d)
D. Excess output level
17.
E4C17 Which of the following has the largest effect on an SDR receiver’s linearity?
a)
A. CPU register width in bits
b)
B. Anti-aliasing input filter bandwidth
c)
C. RAM speed used for data storage
d)
D. Analog-to-digital converter sample width in bits
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