Description : ECE Board Exam March 1996 The modulation system used for telegraphy is A. frequency-shift keying B. two-tone modulation C. pulse-code modulation D. single-tone modulation
Last Answer : A. frequency-shift keying
Description : ECE Board Exam March 1996 SSB transmission requires only ______ of the bandwidth for a DSBFC transmission. A. ¼ B. 2/3 C. ½ D. ¾
Last Answer : C. ½
Description : ECE Board Exam March 1996 What is the transmission rate of a system for transmitting the output of a microcomputer to a line printer operating at a speed of 30 lines/minute? Assume that the line printer has 8 bits ... and prints out 80 characters/line. A. 800 bps B. 400 bps C. 320 bps D. 640 bps
Last Answer : C. 320 bps
Description : ECE Board Exam March 1996 One character or a sequence of characters forming a part, or the whole of a message with a specific meaning A. Signs B. Call sign C. Code D. Identifier
Last Answer : C. Code
Description : ECE Board Exam March 1996 When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ________ wave. A. space or direct B. ground C. surface D. sky
Last Answer : A. space or direct
Description : ECE Board Exam March 1996 An antenna that is circularly polarized is the ____________. A. parabolic reflector B. helical C. Yagi-uda D. small circular loop
Last Answer : B. helical
Description : ECE Board Exam March 1996 That dielectric material of an optical fiber surrounding the core A. Cladding B. Armor C. Shield D. Cover
Last Answer : A. Cladding
Description : ECE Board Exam March 1996 A type of an underground antenna is a/an __________ antenna. A. Hertz B. isotropic C. parabolic D. Marconi
Last Answer : A. Hertz
Description : ECE Board Exam March 1996 The number of voice band channels in master group per CCITT standard is __________. A. 300 B. 480 C. 600 D. 12
Last Answer : A. 300
Description : ECE Board Exam March 1996 TACAN is a navigational aid providing ___________. A. bearing and distance indication B. speed and height indication C. bearing and weather information D. instrument-landing glide paths
Last Answer : A. bearing and distance indication
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 : ECE Board Exam March 1996 Which of the following pulse modulation systems is analog? A. Delta B. Differential PCM C. PWM D. PCM
Last Answer : C. PWM
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 : D. -90 dBm
Description : ECE Board Exam March 1996 Communications code is ____________. A. eight bits per character B. agreed upon in advance between sender and receiver C. the same in all modern computers D. either seven or eight bits per character
Last Answer : B. agreed upon in advance between sender and receiver
Description : ECE Board Exam March 1996 The method of generating FM used by broadcasting station is A. direct B. all of these C. indirect D. insertion
Last Answer : C. indirect
Description : ECE Board Exam March 1996 What is the number of pins in the RS-232C interface? A. 25 B. 15 C. 20 D. 20
Last Answer : A. 25
Description : ECE Board Exam March 1996 The lowest layer in the ionosphere A. D B. F2 C. E D. F1
Last Answer : A. D
Description : ECE Board Exam March 1996 What is the one principal difference between synchronous and asynchronous transmission? A. the pulse height are different B. the clocking is derived from the data in ... C. the clocking is mixed with the data in asynchronous D. the bandwidth required is different
Last Answer : B. the clocking is derived from the data in synchronous transmission
Description : ECE Board Exam March 1996 A car horn outdoors produces a sound intensity level of 90 dB at 10 ft away. At this distance, what is the sound power in watt? A. 12 W B. 0.12 W C. 0.012 W D. 1.2 W
Last Answer : C. 0.012 W
Description : ECE Board Exam March 1996 Passive crossover components cause some frequencies to be delayed with respect to the other frequencies at the crossover point. A. Phase shift B. Phase correction C. Phase-error correction D. Time alignment
Last Answer : A. Phase shift
Description : ECE Board Exam March 1996 According to the Nyquist theorem, the sampling rate that can be used in a PCM system is ________ the highest audio frequency. A. once B. eight times C. twice D. thrice
Last Answer : C. twice
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 The letter-number designation B8E is a form of modulation also known as ___________. A. pilot carrier system B. independent sideband emission C. lincomplex D. vestigial sideband transmission
Last Answer : B. independent sideband emission
Description : ECE Board Exam March 1996 The equivalent noise temperature of the amplifier is 25 K. What is the noise figure? A. 1.86 B. 0.1086 C. 1.086 D. 10.86
Last Answer : C. 1.086
Description : ECE Board Exam March 1996 Judgment on the case against an ECE shall become final and executory after A. 10 days B. 60 days C. 30 days D. 15 days
Last Answer : C. 30 days
Description : ECE Board Exam March 1996 A device to be connected across the headset in telephone receivers to reduce the effects of acoustic shock. A. Ground B. Two rectifiers in parallel with opposite polarities C. Protector D. Fuse
Last Answer : B. Two rectifiers in parallel with opposite polarities
Description : ECE Board Exam March 1996 One type of pulse communications system uses pulse that appear as a group, and which vary in number according to the loudness of the voice. This type of ... A. pulse duration modulation B. pulse amplitude modulation C. pulse code modulation D. pulse position modulation
Last Answer : A. pulse duration modulation
Description : ECE Board Exam March 1996 It is a spacecraft placed in orbit around the earth carrying onboard microwave receiver and transmitting equipments. A. Fiber optic equipment B. Communications satellite C. Wireless radio system D. Coaxial cable syste
Last Answer : B. Communications satellite
Description : ECE Board Exam March 1996 One hundred twenty µbars of pressure variation is equal to A. 120 dBSPL B. 115.56 dBSPL C. 41.58 dBSPL D. 57.78 dBSPL
Last Answer : B. 115.56 dBSPL
Description : ECE Board Exam March 1996 The standard reference antenna for the directive gain is ___________. A. elementary doublet B. isotropic antenna C. half-wave dipole D. infinitesimal dipole
Last Answer : B. isotropic antenna
Description : ECE Board Exam March 1996 Modems are required to connect computer to telephone lines because ___________. A. telephone company rules required them B. the telephone network bandwidth is too high C. none of the above D. the telephone network will pass direct current
Last Answer : D. the telephone network will pass direct current
Description : ECE Board Exam March 1996 The capture area of an antenna is directly proportional to the A. frequency of the received signal B. distance between transmitter and receiver C. gain of the antenna D. power density of the signal
Last Answer : C. gain of the antenna
Description : ECE Board Exam March 1996 The potential difference between any exposed structured to ground in any electrical installation should not exceed _________ volts RMS. A. 10 B. 45 C. 0 D. 30
Last Answer : B. 45
Description : ECE Board Exam March 1996 The point on the satellite orbit, closest to the earth is A. prograde B. perigee C. zenith D. apogee
Last Answer : B. perigee
Description : ECE Board Exam March 1996 What is the purpose of a beat frequency oscillator (BFO)? A. Aid in the reception of weak voice-modulated signals B. Generates a signal, whose frequency is the ... reception D. Generates an output, whose frequency differs from that of the intermediate frequency by 1 kHz
Last Answer : C. Generates a 1kHz note for Morse code reception
Description : ECE Board Exam March 1996 The characteristics impedance of a transmission line does not depend upon its ________. A. conductor spacing B. conductor diameter C. length D. conductor radius
Last Answer : C. length
Description : ECE Board Exam March 1996 Atmospheric condition is controlled by A. humidity B. pressure C. temperature D. all of these
Last Answer : D. all of these
Description : ECE Board Exam March 1996 ___________ occurs when the microwave beam is at point of grazing over an obstacle. A. Diffraction B. Refraction C. Absorption D. Reflection
Last Answer : A. Diffraction
Description : ECE Board Exam March 1996 A receiver connected to an antenna whose resistance is 50 ohms has an equivalent noise resistance of 30 ohms. What is the receiver’s noise temperature? A. 754 K B. 464 K C. 174 K D. 293 K
Last Answer : C. 174 K
Description : ECE Board Exam March 1996 An antenna which is not resonant at a particular frequencies and so can be used over a wide band of frequencies and so can be used over a wide band of frequencies is called A. aperiodic B. boresight C. cassegrain D. top-loaded
Last Answer : A. aperiodic
Description : ECE Board Exam March 1996 The standard that specifies a balanced interface cable that will operate bit rates up to 10 Mbps with in a span distances up to 1200 m. A. RS-423A B. RS-422A C. RS-550A D. RS-449A
Last Answer : B. RS-422A
Description : ECE Board Exam March 1996 EIRP stands for _______________. A. effective isotropic refracted power B. effective and ideal radiated power C. effective isotropic reflected power D. effective isotropic radiated power
Last Answer : D. effective isotropic radiated power
Description : ECE Board Exam March 1996 What is the IBM’s asynchronous data link protocol designation? A. 83 B B. 8A1 / 8B1 C. 93 B D. 9A1/ 9B1
Last Answer : A. 83 B
Description : ECE Board Exam March 1996 The K-factor under normal atmospheric conditions in a microwave radio data profile calculation is equal to ___________. A. 2/3 B. 0 C. 4/3 D. Infinity
Last Answer : C. 4/3
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 : ECE Board Exam March 1996 LORAN is a navigation system used primarily for A. approach control B. obtaining fixes over large distances C. blind landing D. automatic collision warning
Last Answer : B. obtaining fixes over large distances
Description : ECE Board Exam March 1996 The expander in a companding device provides ___________. A. greater amplification for low signal levels B. less amplification for low signal levels C. greater amplification for high signal levels D. lesser pressure for transmission
Last Answer : B. less amplification for low signal levels
Description : ECE Board Exam March 1996 LORAN is a navigational system used primarily for _____________. A. blind landing B. obtaining your fixes location over large distances C. automatic collision warning D. approach control
Last Answer : B. obtaining your fixes location over large distances
Description : ECE Board Exam March 1996 The power of standard test tone is normally ____________. A. 1 dB B. 0 mW C. 1 mW D. 1 W
Last Answer : C. 1 mW
Description : ECE Board Exam November 1996 What is the applied power if a thermal RF wattmeter is connected to a transmitter through a variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation is used. A. 4.656 watts B. 2.656 watts C. 3.656 watts D. 2.856 watts
Last Answer : B. 2.656 watts