
Online Questions and Answers Topic Outline
- MCQs in External Noise
- MCQs in Phase Noise
- MCQs in Noise Calculation and Measurements
- MCQs in Radio Interference
- MCQs in decibel (dB)
MCQs in Noise Series
Following is the list of multiple choice questions in this brand new series:
Continue Practice Exam Test Questions Part V of the Series
201. A power level of 50 µW could be expressed as:
- a. 1.39 dBm
- b. -4.3 dBm
- c. 1 dBm
- d. -13 dBm
202. If a power of 0.25 mW is launched into a fiber system with an overall loss of 15 dB the output power would be:
- a. 250 µ/W
- b. 31.6 µW
- c. 7.9 µW
- d. 15 dBm
203. A system having an input power of 2 mW an output power of 0.8mW has a loss of:
- a. 2.98 dBm
- b. 3.98 dB
- c. 3.98 µW
- d. 1.98 mW
204. An output of -10 dB means that the power has been
- a. Halved in value
- b. Increased by a factor of 10
- c. Reduced by a factor of 10
- d. Doubled
205. Any unwanted form of energy interfering the reception of wanted signal is called
- a. Noise
- b. Sideband
- c. Harmonics
- d. Modulation
206. Is the reduction of signal amplitude as it passed over the transmission medium.
- a. Noise
- b. Distortion
- c. Attenuation
- d. Interference
207. Signal waveform perturbation or deviation caused by imperfect response of the system to the desired signal
- a. Noise
- b. Aliasing
- c. Distortion
- d. Interference
208. Signal attenuation can be corrected by
- a. Filtering
- b. Modulation
- c. Equalization
- d. Amplification
209. Distortion in a waveform can be corrected by
- a. Filtering
- b. Modulation
- c. Equalization
- d. Amplification
210. Signal contamination by extraneous or external sources, such as, other transmitters, power lines, and machinery.
- a. Noise
- b. Distortion
- c. Harmonics
- d. Interference
211. Man-made or industrial noise is also known as
- a. Noise
- b. Distortion
- c. Interference
- d. Thermal Noise
212. The noise performance of a receiver or circuit. It is expressed as ratio of the S/N power at the output.
- a. Noise figure
- b. S/N ratio
- c. Signal figure
- d. Figure of merit
213. Noise that is caused by natural disturbances such as lightning discharge.
- a. Static noise
- b. Space noise
- c. Atmospheric noise
- d. A or C
214. Atmospheric or static noise becomes less severe at frequencies
- a. Below 30 KHz
- b. Between 30 KHz and 300 KHz
- c. Between 300 KHz and 30 MHz
- d. Above 30 MHz
215. Considered as space noise or extraterrestrial noise
- a. Solar noise
- b. Cosmic noise
- c. Black-body noise
- d. All of the above
216. Which statement is true
- a. Industrial noise is usually of impulse type
- b. Distant stars produce atmospheric noise
- c. Active switches are sources of man-made noise
- d. Static noise is due to lightning discharges and other natural electric disturbances occurring in the atmosphere.
217. Noise performance of microwave system is usually expressed in terms of
- a. Noise voltage, Vn = √4KTBR
- b. Noise power, Pn = KTB
- c. Noise temperature, Te = (F – 1)290
- d. Noise figure, F = (S/N)I / (S/N)o
218. Which circuit contributes most to the noise at the receiver?
- a. RF amplifier
- b. Mixer
- c. Detector
- d. Local Oscillator
219. Which noise figure represents the lowest noise?
- a. 1.5 dB
- b. 2.0 dB
- c. 3.7 dB
- d. 4.1 dB
220. Denote the interference of noise in dB above an adjusted reference noise. The adjusted reference noise level was a 1 kHz tone, set at -85 dBm
- a. dBa
- b. dBm
- c. dBa0
- d. pWp
221. The extent of noise referred to a test tone level of zero dBm.
- a. dBa
- b. dBm
- c. dBa0
- d. pWp
222. An amplifier operating over a 4 MHz bandwidth has a 100 Ω input resistance and is operating at 300°K. Determine the noise power generated.
- a. 1.656 x 10-14 Watts
- b. 1656 nW
- c. 1.656 pW
- d. 1.656 uW
223. Generally used when noise readings are measured using the C-message weighting network. The reference level was 1 kHz tone, set at -90 dBm
- a. dBa
- b. dBm
- c. dBaO
- d. dBmC
224. The measurement of noise was made with a C-message filter, and the reading is taken at a test point where the level is zero dBm.
- a. dBaO
- b. dBmCo
- c. dBa
- d. dBmC
225. Which of the following is not an important cause of distortion in DC signaling
- a. line resistance
- b. line inductance
- c. line capacitance
- d. all of the above
226. There are a number of different sources of radio noise, the most important being
- a. Galactic noise
- b. Man-made noise
- c. Atmospheric noise
- d. All of the above
227. The amount of noise power is measured using a psophometric weighting network. This unit of measurement is generally used in Europe where the standard reference tone is 800 hertz, 1 picowatt.
- a. dBa
- b. dBm
- c. dBaO
- d. pWp
228. Noise produced mostly by lightning discharges in thunderstorms.
- a. White noise
- b. Industrial noise
- c. Atmospheric noise
- d. Extraterrestrial noise
229. Propagation of man made noise is chiefly by
- a. Transmission over power lines and by ground wave
- b. Space wave
- c. Sky wave
- d. None of these
230. A more precise evaluation of the quality of a receiver as far as noise is concerned
- a. S/N
- b. VSWR
- c. Noise factor
- d. Noise margin
231. NIF stands for
- a. Non-intrinsic figure
- b. Noise interference figure
- c. Noise improvement factor
- d. Narrow intermediate frequency
232. External noise fields are measured in terms of
- a. Dc values
- b. Rms values
- c. Peak values
- d. Average values
233. Form of interference caused by rain, hail, snow or dust storms
- a. Shot noise
- b. Galactic noise
- c. Impulse noise
- d. Precipitation static
234. Extra-terrestrial noise is observable at frequencies from
- a. 0 to 20 KHz
- b. 8 MHz to 1.43 GHz
- c. 5 to 8 GHz
- d. 15 to 160 MHz
235. Industrial noise is observable from
- a. 15 to 160 MHz
- b. 200 to 3000 MHz
- c. 0 to 10 kHz
- d. 8 Mhz to 1.43 GHz
236. Noise that becomes significant at VHF range and above
- a. Atmospheric
- b. Transit-time
- c. Galactic
- d. White
237. Noise figure for an amplifier with noise is always
- a. 0 dB
- b. Infinite
- c. Less than 1
- d. Greater than 1
238. The noise generated by the tube, transistor or integrated circuit in an amplifier.
- a. White noise
- b. Amplification noise
- c. Active noise
- d. Dynamic Noise
239. Electrical noise inherent to a particular device, circuit or system that remains when no other signal is present.
- a. Shot noise
- b. Thermal noise
- c. Background noise
- d. Static noise
240. A wideband form of impulse noise generated by the electric arc in the spark plugs of an internal combustion engine. This noise is a common problem in mobile radio system.
- a. Thermal noise
- b. Shot noise
- c. Amplification noise
- d. Ignition noise
241. The amount of power in dB referred to one Kilowatt
- a. dBW
- b. dBk
- c. dBm
- d. Dbv
242. Noise in any form of electromagnetic interference that can be traced to non-natural causes.
- a. Man-made noise
- b. Distortion
- c. External noise
- d. Internal noise
243. The frequency range wherein noise is said to be intense.
- a. Noise equivalent bandwidth
- b. Spectral response
- c. Cut-off frequency
- d. Noise cut-off frequency
244. Refers to the temperature that corresponds to the spectral energy distribution of a noise.
- a. Absolute temperature
- b. Temperature band
- c. Noise-equivalent temperature
- d. Critical temperature
245. A passive circuit, usually consisting of capacitance and/or inductance, that I inserted in series with the a-c power cord of an electronic device which will allow the 60-Hz current to pass and suppressed high frequency noise components.
- a. Noise filter
- b. Noise limiter
- c. Noise floor
- d. Noise quieting
246. What do you call the level of background noise, relative to some reference signal.
- a. Noise figure
- b. Minimum noise
- c. Reference noise
- d. Noise floor
247. A circuit often used in radio receivers that prevents externally generated noise from exceeding amplitude. They are also called noise clippers
- a. Noise floor
- b. Noise filter
- c. Noise limiter
- d. Noise clamper
248. It is referred to as a short burst of electromagnetic energy.
- a. Pulse
- b. Noise pulse
- c. Spike
- d. Noise floor
249. The reduction of internal noise level in a frequency-modulated (FM) receiver as a result of an incoming signal.
- a. Noise quieting
- b. Noise limiting
- c. Noise suppression
- d. Noise degradation
250. Noise generated within electronic equipment by either passive or active components.
- a. Shot noise
- b. Thermal noise
- c. Circuit noise
- d. External noise
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