Description : What milliwatt value is equal to +6 dBm?
Last Answer : 4 mW.
Description : If the rf amplifier discussed has an 80 milliwatt input, what would be the maximum output?
Last Answer : 800 watts.
Description : The standard test tone A. 0dB B. 10 dBm C. 0 dBm D. 10 dB
Last Answer : C. 0 dBm
Description : For a single mode optical cable with 0.25 dB/km loss, determine the optical power 100 km from a 0.1-mW light source. ∙ A. -45 dBm ∙ B. -15 dBm ∙ C. -35 dBm
Last Answer : ∙ C. -35 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
Last Answer : 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 : 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 : 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 : Interfering effect of noise, C message weighted, is _________. A. dBa B. dBm C. dBmc D. dB
Last Answer : C. dBmc
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 : 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 : Which stands for dB relative level? A. dBrn B. dBm C. dBr D. dBa
Last Answer : C. dBr
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 : 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 : What is the reference noise level? A. 10 pW B. 0 dBm C. 1mW D. -90 dBm
Description : What is the reference tone level for dBa? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm
Last Answer : D. -85 dBm
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 : What is the reference level for noise measurement, F1A weighted? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm
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 : 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 : 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
Last Answer : When power ratios are expressed in dBm, the reference power is 1 mW.
Description : When measuring receiver sensitivity, what quantities must you add to the dBm reading obtained on the signal generator or test set?
Last Answer : Attenuations of the directional coupler and the connecting cable.
Description : In ball mill operation, the feed size (Df in meters) and the ball diameter (Db in metres) are related as (where, K = grindability constant (varying from 0.9 to 1.4 in increasing order of hardness)) (A) Db 2 = K.Df (B) Db = K.Df (C) Db 3 = K.Df (D) Db 2 = K.Df
Last Answer : (A) Db 2 = K.Df
Description : The gain margin of a system is 0 dB. It represents a (a) Stable system (b) Unstable system (c) Marginally stable system (d) Conditionally stable system
Last Answer : The gain margin of a system is 0 dB. It represents a Marginally stable system
Description : At a distance of 10 meters form a point source, the intensity level is measured to be 70 dB. At what distance form the source well the intensity be 40 dB? How do you solve this?
Last Answer : Going on memory here….3db is half the intensity. The intensity is usually inversely proportional to r squared. The rest is math, so 70–40 is 30 or ten halves.
Description : Which noise figure represents the lowest noise in receiver? A. 1.6 dB B. 2.1 dB C. 2.7 dB D. 3.4 dB
Last Answer : A. 1.6 dB
Description : What is the main difference between a vu and a dB meter?
Last Answer : DB meters are used for measuring sine waves. Vu meters are used to measure the average value of complex waveforms.
Description : While measuring frequency response, as the signal generator approaches the lowest and highest frequency the recorder can effectively record, the VTVM reading drops to less than - 3 dB. What does this indicate?
Last Answer : The upper and lower limits of the frequency response specification for that tape recorder.
Description : The frequency-response specification of your tape recorder reads within +/ - 3 dB from 150 Hz to 150 kHz at 60 ips. What does this mean?
Last Answer : The recorder can record all frequencies between 150 Hz and 150 kHz at 60 ips without varying the output amplitude more than 3 dB.
Description : Two tape recorders have signal-to-noise ratios (SNRs) of 25-dB RMS and 35-dB RMS respectively. Which of the SNRs can record and reproduce the widest range of input signals and why?
Last Answer : 35-dB RMS because the highest SNR can always record and reproduce the widest range of input signals.
Description : Describe the -3 decibel (dB) optical power frequency (f3dB).
Last Answer : The -3 decibel (dB) is the lowest frequency at which the magnitude of the fiber frequency response has decreased to one half its zero-frequency value.
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 : 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 : A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is supplied to one end of the line, how many watts reach the load, 27 m away? A. 10 W B. 7.2 W C. 9.9 W D. 9.1 W
Last Answer : D. 9.1 W
Description : Which of the following statements represents an application of a silicon controlled rectifier? A. To provide DC power for a main propulsion motor. B. For use as a voltage reference diode. C. For sensing flame in an automated burner. D. To eliminate power supply hum.
Last Answer : Answer: A
Description : A station is known to operate at 60-meters. What is the frequency of the unknown station?
Last Answer : 5 megahertz.
Description : What do impedance-angle meters and vector bridges have in common?
Last Answer : Both measure phase angle and magnitude in determining impedance.
Description : What is the advantage of using in-line wattmeters over output power meters?
Last Answer : Most in-line wattmeters are capable of measuring both forward and reflected power.
Description : What are two types of frequency meters?
Last Answer : Vibrating reed and moving disk.
Description : Why is a multimeter preferred over separate meters?
Last Answer : It is much more convenient to have one meter with several functions than several meters each with a single function.
Description : Why is in-circuit meters used?
Last Answer : In-circuit meters are used to monitor the operation of electrical or electronic devices.
Description : What two types of meters can be used to check a switch?
Last Answer : An ohmmeter and a voltmeter.
Description : What meters operate from their own power sources?
Last Answer : Self-excited.
Description : The scientific name of Diamond back moth (DBM) of cabbage
Last Answer : Ans. Plutella xylostella
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 : 15 dBa F1A weighted, equals ___________. A. -90 dBm B. -82 dBm C. -85 dBm D. -70 dBm
Last Answer : D. -70 dBm
Description : F1A weighting refers to ___________. A. -90 dBm B. dBrnc0 C. dBrnc D. F1A handset
Last Answer : C. dBrnc
Description : What is the unit of noise power of psophometer? A. pWp B. dBa C. dBm D. dBrn
Last Answer : A. pWp