100 Questions

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Own version of ESAT board exam.

Questions and Answers
  • 1. 
    In broadband ISDN (B-ISDN), the channel rate of H21 is:
  • 2. 
    The ratio in decibels of the incident power to the reflected power on a transmission line.
  • 3. 
    A circular radio antenna, either in the open or in a streamlined, teardrop housing, remotely turned 360 degrees to fine-tune a station in a league with other radio-directive devices.
  • 4. 
    Also known as IEEE 1394, a scalable, flexible, and low-cost serial digital interlace that connects consumer electronic devices such as video cameras, digital camera, etc. with personal computers.
  • 5. 
    The terminal load capacitance of the RS-232C cable is specified as _____ which includes cable capacitance.
  • 6. 
    The frequency stability of a cellular mobile telephones transmitted authorized by NTC for use in the Philippines.
  • 7. 
    A figure of merit used to measure the dependence of  the signal output of a photodetector on the input radiant power.
  • 8. 
    Calculate the numerical aperture of acceptance angle 20 degree.
  • 9. 
    In a telephone system, what traffic model is based on the assumption, that calls now immediately satisfied at the first attempt are held in the system, until it is satisfied.
  • 10. 
    Calculate the maximum bit rate in Mbps for UPNRZ transmission through a 100 Km cable when the pulse spreading constant for the fiber is 10 nsec/km.
  • 11. 
    Detection and classification of the physical attributes such as fingerprints, voice pattern, or iris or retina of the eye thus, it is used for authorization.
  • 12. 
    Compute the time it takes to send the message CBFE from one station to another serial data transfer if the transfer rate is 1 ms per transfer.
  • 13. 
    A computer hardware and/or software that acts as a buffer between an internal network and the internet to provide security against unauthorized access.
  • 14. 
    A component that samples the microwave signal traveling in one direction down a transmission line.
  • 15. 
    If the input bit rate iof 8PSk is 3kpbs, what is the signal frequency input to the modulator?
  • 16. 
    What is the speed of the Cellular Digital Packet Data, which is one of the oldest devices for sending data over a cellular communications network, and is a CDPD that provides a way passing internet protocol data packets over analog cellular voice networks?
  • 17. 
    What is the synchronous orbit for a comunication sattelite in miles?
  • 18. 
    A metal in a foil launched form a terget to create false radar target.
  • 19. 
    A transmitter supplies 50 Watts to a load through a line with an SWR of 2:1. Find the power absorbed by hte load.
  • 20. 
    The forward power in a transmission line is 150 Watts and the reverse power is 20 Watts. Calculate the SWR on the line.
  • 21. 
    A standard protocol used to connect after packet switching netwrok
  • 22. 
    It minimizes side and blockage radiations from a microwave dish.
  • 23. 
    An open-wire transmission line is made from two wires, each with a diameter of 12 mm located 15 mm apart. Calculate the impedance of the line.
  • 24. 
    It pertains to the change of the crystal oscillcator frequency by loading.
  • 25. 
    What percentage of the primary colors used in color TV are needed to produce the brightest white?
  • 26. 
    In a fiber optic system, the core of PCS fiber is _____ ?
  • 27. 
    Determine the image frequency for a standard broadcast band receiver using a 455 khz IF and tuned to a station at 620 khz.
  • 28. 
    A tuned circuit that dissipates energy taken from another circuit.
  • 29. 
    An ITU-T recommendation which pertains to session protocol specifications for open system interconnection (OSI) for ITU-T application.
  • 30. 
    How may degrees is the phase difference between the I and Q color signal carrier in colored TV sets?
  • 31. 
    What are the typical transmitter-receiver spacing for microwave relay?
  • 32. 
    The values of Vmax and Vmin as read from an Am wave on an oscilloscope are 2.8 and 0.3. The percentage if the modulation is _____?
  • 33. 
    The third symbol radio emission represent telephone transmission sound broadcasting.
  • 34. 
    It is used to calculate the total noise factor of several cascaded amplifiers determined by ?
  • 35. 
    What is the typical value of vidicon dark current?
  • 36. 
    How many voice channels are there in a DS-2 Digital Signal Hierarchy for TDM signals?
  • 37. 
    In measuring the intensity of acoustical signals, the ogarithmic unit decibel (dB) is used. Th threshold of hearing in dB-SPL is _____ ?
  • 38. 
    A rule which is an approximation and gives transmission bandwidths of FM that is slightly narrower than the bandwidths. It defines a bandwidth that includes approximately 98 % of the total power in the modulted wave.
  • 39. 
    A component containing ferrite materials that allows component, but absorbs microwave signals passing in the other directions.
  • 40. 
    What type of filter can be electronically tuned?
  • 41. 
    The frequency change of an electronically tuned oscillator at a specified time after it has reached its desired frequency?
  • 42. 
    A layer in the ionosphere located approximately between 60 miles and 85 miles ( 100 km to 140 km). It is sometimes called the " Kenelly-Heaviside" layer and it totally disassppears at night
  • 43. 
    A study group formed by Conference of European Posts and Telegraphs (CEPT) in 1982 to study the development of a pan-European public land mobile telephone system using ISDN.
  • 44. 
    What is the advantage of cable communication systems compared with a broadcast system?
  • 45. 
    For a carrier frequency of 6GHz and a distance of 50 km, determine the free-space path loss.
  • 46. 
    Who is considered to be the inventor of the modern portable mobile handset used in mobile communications outside the police car mobile technology invented by Bell Labs?
  • 47. 
    A figure of merit used to measure the performance of a radiation detector.
  • 48. 
    A condition when an incoming call meets an outgoing call causing a blockage.
  • 49. 
    The international organization for standardization. It creates the sets of rules and standards for graphics, document exchange, and related technologies. Responsible for endorsing and coordinating the work of the other standards organization.
  • 50. 
    A protocol for interconnecting digital programmable instruments (DPI).
  • 51. 
    What is the effective radiated power of a repeater with 450 Watts transmitting power output, 4 dB Feedline loss, 6 dB duplexer loss, and 7 dB circulato and feedline loss and antenna gain of 25 dB?
  • 52. 
    The protocol used for transmitting e-mail on the Internet
  • 53. 
    A type of RF modulation technique in which the frequency of an analog signal is varied in accordance with the variations in the amplitude of a digital signal.
  • 54. 
    A rectangulat waveguide has a width of 1.2 in and height of 0.7 in. The waveguide will pass all signal above __ Ghz?
  • 55. 
    A sonic frequency lying above audio frequencies ranigng usually above 20 Khz.
  • 56. 
    In microwave, communications system, for a carrier frequecny of ^ghz and a distance of 40 Km, determine the free path space loss in dB?
  • 57. 
    A rectangular waveguide used for microwave transmission has a width of 1.4 in abd height of 0.8 in. All signal above __ GHz will be passed by the waveguide.
  • 58. 
    One-hundred twenty microbars of pressure variation is equal to
  • 59. 
    Calculate the lectric field intensity in mV/m at 30 kW form a 5 km source.
  • 60. 
    A radio wave moves from air (Er=1) to glass (Er=7.8). Its angle of incidence is 20 degress. What is the angle of refraction?
  • 61. 
    Determine the refractive index of an ionoshpere layer with 1.576x10^6 free electrons per cu.m. The frequency of the radio wave is 32 Khz?
  • 62. 
    The period for a single time slot in the GSM-TPMA slot structure is ..... usec?
  • 63. 
    Calculate the phase shift offered by a 75 ft. line using polythylene having dielectric constant of 2.3 and operating on % MHz freq.
  • 64. 
    The ratio pf the separation distance between two co0channel cells and the cell radius is known as co-channel
  • 65. 
    In telecommunications short haul connections refers to a connection not exceeding.... km.
  • 66. 
    A telephone signal takes 2 quarters of a second to reach its designation. Calculate the via net loss necessary for an acceptable amount of echo.
  • 67. 
    The measure of how much information can be propagated through a communications system and is function of bandwidth and transmission time.
  • 68. 
    What is the major disadvantage of a klystron?
  • 69. 
    Are signals used primarily for marine and aeronautical navigation
  • 70. 
    An organization consiting of a representative from national standards bodies from different countries, responsible for development standards to facilitate international trade and services.
  • 71. 
    Are signals often referred to as short waves. Used for most two way radio communications.
  • 72. 
    In CMTS, the most important database in a GSM network is:
  • 73. 
    The data rate of information transfer among mobile devices using "Bluettoth technology" is.
  • 74. 
    Are signals that include the majority of the frequencies used fir microwave and satellite radio communications systems
  • 75. 
    A radarmile is the time required for a radar pulse to travel one mile to an object and return to the receiver.  One radar nautical mile is equivalent to how many usec?
  • 76. 
    What power in watts is required of an 8 W is necessary for a binary code?
  • 77. 
    Is the range of frequencies contained in the spectrum.
  • 78. 
    In radio communications, what do you call a point on a line, between the Earth's center an observer, located farther from the Earth's center than the point?
  • 79. 
    These are intended to carry data is suitable traspondersm generally known as tags, and to retrieve data, and place to satidfy particular application needs.
  • 80. 
    The outline of the peaks of a carrieer has the shape of the modulating signal and is called the?
  • 81. 
    Stationary two loop RDF system
  • 82. 
    A protected database that holds a copy of the secret key stored in each subscriber's SIM card.
  • 83. 
    Waveguide tuning components is not easily adjustable?
  • 84. 
    What is the station spacing form Am channel allocation in the Philippines?
  • 85. 
    Engr. D. Matira usess tone - dialing phone to dial the number 784-3742. If the digits push button are held down for a 0.25 sec and the interdigit time is also 0.25 sec, how long will it take him to dial the same number?
  • 86. 
    In a radar system set up by the police to tract speed violators, calculate the lowest value of radar pulse repetition frequency (PRF) that can be used to ensure that the first blind speed is above 55 Km per second (the length used is 15 cm).
  • 87. 
    Grounding system of an AM broadcasting tower radiator may be improved using radial wires known as
  • 88. 
    GPS precise positioning service (PPS) vertical accuracy:
  • 89. 
    Wireless Internet Service Provider use Wi-Fi technology to provide internet access to airports, hotels, convention centersm coffee shops, and other public places. When users are within the range of an antenna, WISP offer access to the internet at speed up to ____ Mbps
  • 90. 
    Which of the standards is for terrestrial digital TV transmission
  • 91. 
    If the refractive index of the core of an optic wa s1.47 and that of the cladding was 1.44, the angle of acceptance is
  • 92. 
    MPEG-2 video compression used discrete ____ trasform algorithm
  • 93. 
    Crosstalk in telephony, refers to the unwanted coupling between signal paths and contribute to noise in the telephone receiver. calculate the cross talk coupling loss in dBx (one unit crosstalk in dB above reference coupling if the crosstalk  coupling is 20 dBx)
  • 94. 
    The distributed parameters of the transmission lines are: the series resistance; the series inductance; the shunt capacitance and the shunt conductance. What parameter was determined due to dielectric losses?
  • 95. 
    In telephony, M88 loading coil (38 mH loading coil) is palced at an interval of ___ ft.
  • 96. 
    What service is provided by bradband ISDN (B-ISDN) provider, that offer a means for biochemical end-to-end data transmission, in real time, between two subcriber or between a subscribr and the service provider called?
  • 97. 
    An AM signal has a carrier power if 5W. The percentage of modulation is 80%. The total sideband power is
  • 98. 
    Bar codes are those omnipresent black and white striped stickers that often times appear on almose every consume items in the US and in the philippines. Code 39 is an exmaple of what type of bar code?
  • 99. 
    A deceptive jamming technique where the jamming signal is given a false Dopple shift so that the radar thinks the target velocity is different that its really is.
  • 100. 
    A method of comparing two audio system by switching inputs sot he same recording is heard in rapid succession over one system and the other.