Description : The most common unit of noise measurement in white noise testing. A. dBw B. dBk C. dBm D. NPR
Last Answer : D. NPR
Description : What is the unit of noise power of psophometer? A. pWp B. dBa C. dBm D. dBrn
Last Answer : A. pWp
Description : Reference noise is ___________. A. a 1000 Hz, -90 dBm tone B. a noise that creates the same interfering effect as a 1000Hz, -90dBm tone C. a noise that creates zero dBrn in a voice channel D. B and C above
Last Answer : D. B and C above
Description : What is the reference tone level for dBrn? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm
Last Answer : A. -90 dBm
Description : Which stands for dB relative level? A. dBrn B. dBm C. dBr D. dBa
Last Answer : C. dBr
Description : What is the reference level for noise measurement, F1A weighted? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm
Last Answer : D. -85 dBm
Description : A practical dBrn measurement will almost always in a _______ number. A. positive B. negative C. imaginary D. fractional
Last Answer : A. positive
Description : Unit of noise power of psophometer A. dBa B. pWp C. dBm D. dBmO
Last Answer : B. pWp
Description : A measurement of -75 dBm, C-message weighted, would be _________ dBrnc. A. 8 B. 7 C. 9 D. 15
Last Answer : D. 15
Description : You are measuring noise at a -6 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -59 dBm. This is _________ dBa0. A. 24 B. 12 C. 23 D. 32
Last Answer : D. 32
Description : Interfering effect of noise, C message weighted, is _________. A. dBa B. dBm C. dBmc D. dB
Last Answer : C. dBmc
Description : What is the reference noise level? A. 10 pW B. 0 dBm C. 1mW D. -90 dBm
Last Answer : D. -90 dBm
Description : What is the noise factor if the equivalent noise temperature is 25 K? A. 1.09 B. 0.09 C. 0.36 dBm D. 0.36
Last Answer : A. 1.09
Description : You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What is the reading in dBrnc? A. 20 B. 32 C. 35 D. 25
Last Answer : C. 35
Description : Noise reduction system used for film sound in movie A. dBx B. dolby C. dBa D. dBm
Last Answer : B. dolby
Description : In measuring noise in a voice channel at a 4 dB test point level, the meter reads -70 dBm (F1A weighted), convert the reading to pWp. A. 53 B. 93 C. 63 D. 83
Last Answer : B. 93
Description : A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of 8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW. A. 50 B. 69 C. 49 D. 30
Last Answer : C. 49
Description : Reading a 58 dBrn, at a +7 test point is equal to ________ dBa0. A. 26 B. 65 C. 51 D. 46
Last Answer : D. 46
Description : What is the reference frequency of CCIT phosphomeric noise measurement? A. 800 Hz B. 1000 Hz C. 1500 Hz D. 3400 Hz
Last Answer : A. 800 Hz
Description : What is the reliable measurement for comparing amplifier noise characteristics? A. Thermal agitation noise B. Noise factor C. Noise margin D. Signal-to-noise
Last Answer : B. Noise factor
Description : What is the reference frequency of CCITT psophometric noise measurement? A. 800 Hz B. 1500 Hz C. 3400 Hz D. 1000 Hz
Description : What is the reference tone level for dBa? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm
Description : At what power level does a 1 KHz tone cause zero interference (144 weighted)? A. 90 dB B. 90 dBm C. -90 dBm D. -90 dBm
Description : Your Western Electric 3A test set meter reading is -23 dBm at at test point level of -8 dB. This is ______ dBrnc0. A. 75 B. 29 C. 30 D. 31
Last Answer : A. 75
Description : 15 dBa F1A weighted, equals ___________. A. -90 dBm B. -82 dBm C. -85 dBm D. -70 dBm
Last Answer : D. -70 dBm
Description : A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair equals _____ dB of crosstalk coupling. A. 20 B. 30 C. 60 D. 25
Last Answer : B. 30
Description : F1A weighting refers to ___________. A. -90 dBm B. dBrnc0 C. dBrnc D. F1A handset
Last Answer : C. dBrnc
Description : The difference between signal strength at a given point and a reference level is________. A. power B. dBm C. level D. ratio
Last Answer : C. level
Description : The standard test tone A. 0dB B. 10 dBm C. 0 dBm D. 10 dB
Last Answer : C. 0 dBm
Description : You are measuring a voice channel at a -4 dB test point level, the meter reads -73 dBm (pure test tone) convert the reading in dBmCO. A. 16 B. 18 C. 22 D. 12
Last Answer : C. 22
Description : What is the equivalent output of a circuit in dBm, if it is has an output of 10 watts? A. 10 dBm B. 30 dBm C. 20 dBm D. 40 dBm
Last Answer : D. 40 dBm
Description : ECE Board Exam March 1996 What is the reference tone level for dBm? A. -82 dBm B. -85 dBm C. -67 dBm D. -90 dBm
Description : ECE Board Exam March 1996 Crosstalk coupling is ___________. A. dBm (disturbing pair) minus dBm (disturbed pair) B. the difference between readings on a cable pair with a tone and a cable pair without ... a cable C. signals from one circuit that get into another circuit D. All of these are true
Last Answer : D. All of these are true
Description : ECE Board Exam March 1996 At what power level does a 1 kHz tone cause zero interference (144 weighted) ? A. -90 dB B. -90 dBm C. 90 dBm D. 90 dB
Last Answer : B. -90 dBm
Description : ______ is a term in the test language for noise testing in telephone circuits that means a one-syllable word consisting of a consonant, a vowel, and another consonant. A. Logatom B. Nosfer C. Ore D. Belcore
Last Answer : A. Logatom
Description : ___________ is device that measures the internal open circuit voltage of an equivalent noise generator having an impedance of 600Ω and delivering noise power to a 600 Ω load. A. Psophometer B. Barometer C. Reflectometer D. Voltmeter
Last Answer : A. Psophometer
Description : The square of the thermal noise voltage generated by a resistor is proportional to A. its resistance B. its temperature C. the bandwidth over which it is measured D. All of the above
Last Answer : D. All of the above
Description : What is the noise voltage across a 300Ω input resistance to a TV set with a 6MHz bandwidth and temperature of 30˚C? A. 2.3 µV B. 3.8µV C. 5.5µV D. 5.4µV
Last Answer : C. 5.5µV
Description : One of the following is not a useful quantity for comparing the noise performance receivers. A. Input noise voltage B. Equivalent noise resistance C. Noise temperature D. Noise figure.
Last Answer : A. Input noise voltage
Description : The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, ... this two stage amplifier. A. 2,518 kΩ B. 2,518 Ω C. 251.8 Ω D. 12,518 Ω
Last Answer : B. 2,518 Ω
Description : An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient temperature is 17˚C ? A. 40 µV B. 4.0 µV C. 400 µV
Last Answer : B. 4.0 µV
Description : Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type.
Last Answer : B. Impulse noise voltage is dependent on bandwidth
Description : Indicate the false statement A. The noise generated in a resistance or the resistive component of any impedance is random. B. Random noise power is proportional to the bandwidth over which is measured ... exist D. All formula referring to random noise are applicable only to the value of such noise.
Last Answer : C. A random voltage across the resistor does not exist
Description : 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
Last Answer : B. Sun
Description : At 17˚ C, the noise voltage generated by 5kΩ resistor, operating over a bandwidth of 20KHz is A. 1.3 nV B. 1.3 µV C. 1.3 pV D. 1.3 mV
Last Answer : B. 1.3 µV
Description : Two resistors, 20kΩ, and 50kΩ are at ambient temperature. Calculate for a bandwidth equal to 100kHz, the thermal noise voltage for the two resistors connected in parallel. A. 0.4782µV B. 4278 µV C. 4.78 µV D. 47.8 µV
Last Answer : C. 4.78 µV
Description : Which noise is produced by lighting discharges in thunderstorms? A. White noise B. Extraterrestrial noise C. Industrial noise D. Atmospheric noise
Last Answer : D. Atmospheric noise
Description : _________ is measured on a circuit when it is correctly terminated but does not have any traffic. A. White noise B. Galactic noise C. Impulse noise D. Atmospheric noise
Last Answer : A. White noise
Description : One of the following is not among the advantages of series modulation A. No transformer B. Suppressed white noise C. Simple D. Modulates any frequency
Last Answer : B. Suppressed white noise
Description : Noise caused by the thermal agitation of electrons in resistance. A. All of these B. Thermal noise C. Johnson’s noise D. White noise
Last Answer : A. All of these