Description : You determine receiver sensitivity by measuring the power level of what signal?
Last Answer : Minimum discernible signal (mds).
Description : When measuring harmonic distortion, you set the signal generator to input a 15-kHz test signal. To what frequency should you set the wave analyzer?
Last Answer : 45 kHz.
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 : 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 : 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 : 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 : 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 : A loss of receiver sensitivity has the same effect on range performance as what other loss?
Last Answer : Transmitter power loss.
Description : Which amplifier stage (the preamplifier or the postamplifier) is a dominant contributor of noise and significantly influences the sensitivity of the receiver?
Last Answer : The preamplifier.
Description : What is the main factor that determines receiver sensitivity?
Last Answer : Noise
Description : ECE Board Exam March 1996 What is the purpose of the receiver's squelch circuit? A. To overcome fluctuations in the level the RF signal arriving at the receiver antenna B. To prevent ... signals D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal
Last Answer : D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal
Description : Which of the following statements regarding the use of a current measuring instrument is correct? A. It must be connected in series with the circuit. B. You should always start with the lowest range ... of polarity. D. An external shunt is generally utilized where current is less than 10 amperes.
Last Answer : Answer: A
Description : An error signal is the difference between what two quantities fed to the CT (error detector)?
Last Answer : Input signal and feedback.
Description : Which component of the receiver produces the signal that is mixed with the received signal to produce the IF signal?
Last Answer : Local oscillator.
Description : what causes the initial and final pulses on the receiver output signal?
Last Answer : Leakage from the duplexer.
Description : . Which part of the receiver amplifies the electrical signal to a level suitable for further signal processing?
Last Answer : Amplifier.
Description : What does a tone control circuit in a receiver do to the audio signal?
Last Answer : It controls the amount of bass and treble response.
Description : In reference to dB meters, 0 dBm represents 1 milliwatt into what value of load?
Last Answer : 600-ohm load.
Description : What milliwatt value is equal to +6 dBm?
Last Answer : 4 mW.
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 : 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 : What four basic functions must a receiver perform?
Last Answer : Reception, selection, detection, and reproduction.
Description : What limits the sensitivity of a receiver? A. The power supply of the receiver B. The power output of a transmitter C. The noise floor of the receiver D. The distance between the transmitter and receiver
Last Answer : C. The noise floor of the receiver
Description : Define selectivity and sensitivity of AM Receiver.
Last Answer : Selectivity:-It needs to accept signals of the wanted frequency and reject other unwanted frequencies. Sensitivity:-The sensitivity of a radio receiver is its ability to amplify weak signals. It is ... the receiver input terminals to give a standard output power, measured at the output terminals.
Description : Explain the following characteristics of AM radio receiver: (i) Sensitivity (ii) Selectivity.
Last Answer : Sensitivity:- The ability to amplify the weak signals is called sensitivity. It is the function of overall receiver gain. Sensitivity of radio receiver is decided by the gain of the RF IF ... perfectly the receiver is able to select the desired carrier frequency and reject other frequencies.
Description : Name the three main sections of a typical rf signal generator.
Last Answer : Oscillator circuit, modulator, and output control circuit.
Description : Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or ... under test, both working at the same temperature over the same bandwidth and fed from the same source
Last Answer : C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals
Description : Define following terms related to measuring instruments: i) Sensitivity ii) Selectivity.
Last Answer : i) Sensitivity: It is the ratio of the change in output signal to the change in input signal of quantity being measured. ii) Selectivity: It is the term to describe fulfillment of the requirements of measurement by an instrument to be suitable for use in a given situation.
Description : Protective relays are devices that detect abnormal conditions in electrical circuits by measuring (a) current during abnormal condition (b) voltage during abnormal condition (c) constantly the electrical quantities which differ during normal and abnormal conditions (d) none of the above
Last Answer : (c) constantly the electrical quantities which differ during normal and abnormal conditions
Description : Before measuring an unknown resistance with an ohmmeter, you should _____________. A. adjust the meter's pointer to mid-scale B. short the test leads and calibrate the meter reading to 'zero' C. change the meter's batteries D. center the meter's pointer at infinity
Last Answer : Answer: B
Description : The standard test tone A. 0dB B. 10 dBm C. 0 dBm D. 10 dB
Last Answer : C. 0 dBm
Description : What generator characteristics must be considered when alternators are synchronized for parallel operation?
Last Answer : Output voltage, frequency, and phase relationships.
Description : Before you connect a VOM in a circuit for an ohmmeter reading, in what condition must the circuit be?
Last Answer : De-energized
Description : The voltage output of an AC generator is accurately controlled by _____________. A. changing the sensitivity of the prime mover to large changes in voltage B. varying the reluctance of the air gap C. varying the DC exciter voltage D. shorting out part of the armature windings
Last Answer : Answer: C
Description : What term is used to describe the reciprocal of deflection sensitivity of a scope?
Last Answer : Deflection factor.
Description : Which preamplifier design (high-impedance or transimpedance) provides improvements in bandwidth and greater dynamic range with some degradation in sensitivity from an increase in noise?
Last Answer : Transimpedance.
Description : How is fiber sensitivity to bending losses reduced?
Last Answer : Fiber sensitivity to bending losses can be reduced if the refractive index of the core is increased and/or if the overall diameter of the fiber increases.
Description : What is voltmeter sensitivity?
Last Answer : It is an indication of the resistance of the meter expressed in ohms per volt. The total resistance of the meter is the sensitivity multiplied by the full-scale voltage.
Description : What is ammeter sensitivity?
Last Answer : The amount of current that will cause full-scale deflection.
Description : What term is used to express the sensitivity of a voltmeter?
Last Answer : Ohms per volt
Description : (True or False) The larger the current required to produce full-scale deflection of the meter coil, the better the sensitivity of the meter.
Last Answer : False.
Description : The pump signal frequency must be of what value when compared to the input signal of a simple parametric amplifier?
Last Answer : Exactly double the input frequency.
Description : In single-phase alternators, in order for the voltages induced in all the armature windings to add together for a single output, how must the windings be connected?
Last Answer : In series.
Description : Which of the following quantities are to be calculated for generator bus a) P and V b) V and δ c) δ and Q d) Q and P
Last Answer : c) δ and Q
Description : Oscilloscopes are used to measure what quantities?
Last Answer : Amplitude, phase, time, and frequency.
Description : . What type of synchro system is used to transmit very large quantities?
Last Answer : A tri-speed synchro system.
Description : What are the three fundamental quantities involved in radar displays?
Last Answer : Range, bearing, and elevation.
Description : Boolean algebra is based on the assumption that most quantities have _______ conditions.
Last Answer : Two.
Description : When you are using an ohmmeter to test a transistor for leakage, what is indicated by a low, but not shorted, reverse resistance reading?
Last Answer : A leaking transistor