ECE Noise Q&A

1. What is a non-continuous noise of irregular pulses or spikes of short duration with high amplitudes?
A. Wander
(B) Jitter
C. Hits
D. Singing
2. What theorem sets a limit on the maximum capacity of a channel with a given noise level?
A. Nyquist theorem
B. Hartley law
(C) Shannon-Hartly theorem
D. Shannon theorem
3. Quanting noise occurs in
(A) PCM
B. PLM
C. PDM
D) PAM
4. Noise always affect the signal in a communication system at the ______.
A. transmitter
(B) channel
C. information
D. destination
5. A particular circuit that rids FM of noise.
A. Detector
B. Discriminator
C. Phase shifter
(D) Limiter
6. Unwanted radio signal on assigned frequency.
A. Spatter
B. RFI
(C) Noise
D. EMI
7. Which standard recommends crosstalk limits?
A. CCITT G. 152
B. CCITT G. 150
(C) CCITT G. 151
D. CCITT G. 161
8. What is the reference frequency of CCITT phosphometric noise measurement?
(A) 800 Hz
B. 1000 Hz
C. 1500 Hz
D. 3400 Hz
9. Reference temperature used in noise analysis.
A. 75 K
B. 250 K
(C) 290 K
D. 300 K
10. Man-made noise is usually from ______.
(A) Transmission over power lines and by ground wave
B. sky-wave
C. space-wave
D. troposphere
11. External noise fields are measured in term of _____.
A. rms values
B. dc values
C. average values
(D) peak values
12. Form of interference caused by rain or dust storms.
(A) Precipitation static
B. Shot-noise
C. Gallactic noise
D. Impulse noise
13. Is the interference coming from other communication channels.
A. Jiller
(B) Crosstalk
C. RFI
D. EMI
14. What is the unit of noise power of psophometer?
(A) pWp
B. dBa
C. dBm
D. dBrn
15. Atmospheric noise is known as ____ noise.
(A) static
B. cosmic
C. solar
D. lunar
16. If bandwidth is doubled, the signal power is _____.
(A) not changed
B. quadrupled
C. tripled
D. doubled
17. The difference between signal strength at a given point and a reference level is _____.
A. power
B. dBm
(C) level
D. ratio
18. F1A weighting refers to _____.
A. -90 dBm
B. dBrnc0
C. dBrnc
(D) F1A handset
19. Reading a 58 dBrn, at a+7 test point is equal to _____ dBa0.
A. 26
B. 65
C. 51
(D) 46
20. What is the reference tone level for dBrn?
(A) -90 dBm
B. -82 dBm
C. -67 dBm
D. -85 dBm
21. Atmospheric noise becomes less severe at frequencies
(A) above 30 MHz
B. below 30 MHz
C. Above 3000 kHz
D. below 3000 kHz
22. Which of the following is not a source of industrial noise?
A. Automobile ignition
(B) Sun
C. Electric motors
D. Leakage from high voltage line
23. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore
A. halved
B. quadrupled
C. doubled
(D) unchanged
24. Which of the following is not a source of external noise?
(A) Thermal agitation
B. Auto ignition
C. The sun
D. Fluorescent light
25. Noise at the input to a receiver can be as high as several
(A) microvolts
B. millivolts
C. volts
D. kilovolts
26. Which noise figure represents the lowest noise?
(A) 1.6 dB
B. 2.1 dB
C. 2.7 dB
D. 3.4 dB
27. The transiror with the lowest noise figure in the microwave region is a
A. MOSFET
B. Dual-gate MOSFET
C. JFET
(D) MESFET
28. The solar cycle repeats the period of great electrical disturbance approximately every
(A) 11 years
B. 10 years
C. 9 years
D. 8 years
29. Noise consisting of irregular pulses of short duration and relatively high amplitude.
A. Quantizing noise
B. Tone interference
(C) Impulse noise
D. Crosstalk
30. Noise that occurs via capacitive or inductive coupling in a cable
(A) Crosstalk
B. Quantizing noise
C. Reference noise
D. Tone interference