-wire and wireless communications Typical speech power a. 10 to 1000 µW b. 100 to 1000 mW c. 10 to 1000 nW d. 100 to 1000 pW ans: a The maximum intelligibility for voice frequency is located between a. 250 and 500 Hz b. 1000 and 3000 Hz c. 500 and 1000 Hz d. 3000 and 5000 Hz ans: b The maximum voice energy is located between a. 250 and 500 Hz b. 1000 and 3000 Hz c. 500 and 1000 Hz d. 3000 and 5000 Hz ans: a A device used to measure speech volume. a. speech meter b. volume meter c. volume unit meter d. speedometer ans: c By definition, for a sine wave a. 0 dBm = 0 V.U. b. 0 dBW = 0 V.U. c. 0 dBa = 0 V.U. d. 0 dBf = 0 V.U. ans: a Presently, this is the "standard" frequency bandwidth for voice transmission a. 0 to 4000 Hz b. 100 to 3400 Hz c. 300 to 3400 Hz d. 300 to 3000 Hz ans: c Which of the following is commonly used wire for subscriber loop design? a. AWG # 19 b. AWG # 18 c. AWG # 30 d. AWG # 33 ans: a The resistance limit for No. 2 Crossbar Exchange (US) is a. 1300 ohm(s) b. 2000 ohm(s) c. 1250 ohm(s) d. 1200 ohm(s) ans: a AWG # 26 has a typical loss of a. 0.21 dB/1000 ft.
b. 0.32 dB/1000 ft. c. 0.41 dB/1000 ft. d. 0.51 dB/1000 ft. ans: What is the standard voice channel spacing? a. 44 MHz b. 40 kHz c. 4 kHz d. 40 MHz ans: Which tester is used to measure SWR? a. Multimeter b. Oscilloscope c. Spectrum analyzer d. Reflectometer ans: d What is singing? a. The result of intermodulating two or more signals of different frequencies to produce a tone having a frequency equal to the sum of the frequencies of the signals intermodulated. b. The result of intermodulating two or more signals of different frequencies to produce a tone having a frequency higher than that of the signal having the h ighest frequency. c. An undesired self-sustained oscillation in a system, generally caused by ex cessive positive feedback. d. An art or a form of entertainment that can make one rich. ans: c Which stage increases the selectivity of the circuit in an AM receiver? a. Detector b. IF stage c. Modulator d. Mixer ans: b The __________ of radio receiver amplify weak signal and produce a desirable i ntelligence at the output speaker. a. sensitivity b. selectivity c. reliability d. fidelity ans: a Full-duplex transmission means a. one-way transmission b. 24-hour transmission c. broadcast transmission d. two-way simultaneous transmission ans: d What is a multidrop line? a. A piece of wire with a thick insulating material that serves to protect the conductive materials from damage in the event the wire is dropped. b. A line designed to withstand high pressure. c. A line or circuit interconnecting several stations d. A bus line. ans: c
A passive _________ is an electronic device which reduce signal strength by a specified amount in dB. a. splitter b. filter c. trimmer d. attenuator ans: d The signal quality of the calls is constantly monitored by the base station, w hen the quality of the calls drops below a certain specified level, the base req uest the MTSO to try and find a better cell site. a. Hand-off b. Cell splitting c. Roaming d. Frequency reuse ans: c A digital identification associated with a cellular system. a. SAT b. SID c. ESN d. MIN ans: d How many seconds does facsimile transmit a standard page? a. 5 b. 10 c. 20 d. 25 ans: d A kind of recording is used in facsimile. a. Electrolytic recording b. Electrothermal recording c. Electropercussive recording d. Electrostatic recording ans: a A type of distortion a facsimile produces when it becomes out of synchronizati on. a. Pincushion b. Barrel c. Skewing d. Fattening ans: c What is an acoustic coupler? a. A device that radiates audible signals via a transmitting antenna b. A device that converts electric signal signals into audio signals, enabling data to be transmitted over the public telephone network via a conventional tel ephone handset c. A device that receives audible signals and retransmits them at VHF frequenc ies d. A transducer ans: b Cause a herringbone pattern in facsimile. a. Single-frequency interference b. Crosstalk
c. Phase jitter d. Noise ans: b The _________ in an FM receiver causes a stronger signal to dominate over a we aker signal on the same frequency. a. capture effect b. flywheel effect c. hall effect d. skin effect ans: a A device that converts a 2-wire circuit to a 4-wire circuit. a. RS-232 interface b. Hybrid circuit c. Balun d. Stub ans: b __________ theory is deciding between a set of hypotheses when given a collect ion of imperfect measurements. a. Estimation b. Traffic c. Decision d. Nyquist ans: c __________ of a data reduction says that when reducing a set of data into the form of an underlying mode, one should be maximally non-committal with respect t o missing data. a. Jaynes maximum entropy principle b. Kullback principle of minimum discrimination c. Minimum discrimination d. Maximum entropy ans: a __________ is selecting the best value of a parameter from a continuum of poss ible values when given a collection of imperfect measurements. a. Estimation b. Traffic c. Decision d. Nyquist ans: a Combination of modulator, channel, and detector. a. Transceiver b. Transponder c. T/R channel d. Discrete channel ans: d What is the frequency band of DECT? a. 1.88 - 1.90 GHz b. 1.68 - 1.70 GHz c. 1.48 - 1.50 GHz d. 1.28 - 1.30 GHz ans: a How many simultaneous calls does each DECT system can support? a. 96
b. 12 c. 24 d. 49 ans: b How many simultaneous calls does a DECT radio transceiver can assess at any gi ven time? a. 120 b. 240 c. 480 d. 960 ans: a The AGC voltage of a radio receiver is always ________. a. present before adjustments can me made b. DC, but may have either polarity c. positive DC d. negative ans: b What is a concentrator? a. A system that improves the signal-to-noise ratio by compressing the volume range of a signal. b. A device that varies the characteristics of a carrier signal in accordance with the waveform of a modulating signal which contains useful information. c. A switching system that lets a large number of telephone or data processing subscribers use a lesser number of transmission lines or a narrower bandwidth. d. An equipment in the central office. ans: c If you find that an SAW filter output is 6 dB down from the input of a receive r during test, ______________ a. this is normal b. the device is faulty c. the filter is improperly terminated d. the filter is not resonating ans: a A triple conversion superheterodyne receiver, diode mixer stages are a. operated in the linear region b. operated in the nonlinear region c. operated as Class-A amplifiers d. operated as Class-B amplifiers ans: b What is a leased line? a. A piece of wire used in a local area network in one building b. A piece of wire connecting a telephone set to a PABX c. A temporary connection of one computer to a mainframe via a modem and a tel ephone line d. A permanent circuit for private use within a communication network ans: d If two FM signals of different strengths are received on the same frequency a. one steady heterodyne will appear in the AF output b. both will appear in the AF output c. only the stronger will appear in the AF output d. neither signal will be intelligence unless the weaker signal is at least 10 times ans: c
Cellular mobile system was first operated in a. 1979 b. 1981 c. 1983 d. 1985 ans: c TACS is a cellular system with ____________ channels. a. 666 b. 1000 c. 832 d. 200 ans: b Supervisory Audio Tone (SAT) has _______ frequency. a. 5960 Hz b. 6000 Hz c. 6040 Hz d. 1004 Hz ans: b What is the number of channels of a cellular system with an allocated spectrum of 25 MHz and with a channel of 30 kHz bandwidth? a. 833 b. 240 c. 1000 d. 666 ans: a GSM uses what digital modulation technique? a. QAM b. GFSK c. BPSK d. GMSK ans: d What is the power output of Personal Communications System (PCS)? a. 10 mW b. 75 mW c. 150 mW d. 10 W ans: a RG-58 cable has a loss of about ___________ dB at cellular frequencies up to 1 5 feet length. a. 2 b. 1 c. 4 d. 3 ans: d The signals designed to keep the receivers and transmitters aligned. a. Carrier frequencies b. Pilot carrier signals c. Synchronizing signals d. Reference signals ans: b If the spacing of a two-wire open air transmission line is 12 inches and the c
onductor diameter is 0.25 inch, the characteristic impedance is a. 547 ohm(s) b. 357 ohm(s) c. 273 ohm(s) d. 300 ohm(s) ans: a The impedance of the quarterwave transformer used to match a 600 ohm(s) line t o a 300 ohm(s) load is a. 382 ohm(s) b. 424 ohm(s) c. 565 ohm(s) d. 712 ohm(s) ans: b When a line and a load are match the reflection coefficient is a. unity b. zero c. positive infinity d. negative infinity ans: b When line is terminated in an open circuit load, the reflection coefficient is a. unity b. zero c. infinity d. negative unity ans: a A 300 ohms line is terminated in a resistive load of 200 ohms, the VSWR is a. 0.66 b. 1.5 c. unity d. zero ans: b If the reflection coefficient is 0.5, the standing wave ratio is a. 0.33 b. unity c. 3 d. zero ans: c To test the fault of a given line, a signal is fed to the line, 30 µs later the signal returned. What is the distance of the fault? a. 9000 m b. 300 m c. 100 m d. 4500 m ans: d The telephone set is powered by the central office on the ring side at a. 42 to 52 Vdc b. -42 to -52 Vdc c. 24 to 64 Vdc d. -24 to -64 Vdc ans: b The telephone voice band frequency is from
a. 300 b. 400 c. 300 d. 400 ans: c
to to to to
4 kHz 3400 Hz 3400 Hz 4 kHz
Which of the following wire is used to transmit the signal? a. Black b. Yellow c. Red d. Green ans: d The corresponding frequencies for digit 7 in the touch tone telephone is a. 770 and 1477 Hz b. 852 and 1209 Hz c. 852 and 1336 Hz d. 770 and 1336 Hz ans: b The physical connection between the telephone set and the switching equipment is called the a. trunk line b. link c. subscriber loop d. leased line ans: c What is the local loop of a telephone system? a. It is a two-wire or four-wire communication circuit between the customer's premise and the central office. b. It is a group of wires connecting a telephone set to a modem. c. It is a four-wire circuit connecting a facsimile machine to a computer. d. It is a single piece of wire connecting the subscriber's telephone set to a nother set in an adjacent room. ans: d Which of the following equipment is used in long loop design? a. Dial long lines b. Voice repeater c. Loop range extender d. All of the above ans: d What is a two-wire circuit? a. A circuit usually in the subscriber loop, between the telephone set and the local central office. b. A circuit having only two terminals, both terminals having the same instant aneous voltage. c. A circuit with one input terminal, one output terminal, and a common ground . d. A circuit consisting of two transmission lines. ans: a 1 mW is equal to a. 90 dBrn b. 0 dBrn c. -30 dBrn d. 120 dBrn ans: a
Which of the following responds to the request of a subscriber by sending a di al tone? a. Line finder b. First selector c. Connector d. Line equipment ans: b The other name of Class 2 office in the North American Switching Plan. a. Primary center b. Section c. Regional center d. Toll points ans: b A cell in the cellular telephone system means a. a power source b. small area c. large area d. service area ans: b What is the linking point between cell phone and regular telephone? a. Base station b. Control office c. C.O. d. MTSO ans: d What is the typical power output of a cellular phone? a. 5 W b. 10 W c. 1 W d. 3 W ans: d When a single cell is subdivided into smaller cells the process is called a. cell splitting b. cell division c. reuse d. cell sharing ans: a The first cell shape is a a. square b. circle c. rectangle d. triangle ans: b In order to provide 100% coverage without overlap, cellular telephone system c an use a. hexagon cell shape b. triangle c. rectangular d. all of the above ans: d What is the beamwidth of the reflector of the receiving antenna in the base st
ation? a. 20 degrees b. 30 degrees c. 50 degrees d. 60 degrees ans: d A cellular phone operates on a. half duplex b. full duplex c. echoplex d. lincomplex ans: b Cellular phones transmit in the band from a. 825 to 845 MHz b. 835 to 855 MHz c. 825 to 855 MHz d. 825 to 865 MHz ans: a Cell phone receives in the band from a. 860 to 880 MHz b. 870 to 890 MHz c. 870 to 880 MHz d. 860 to 890 MHz ans: b What is the frequency separation between the transmit and the receive channels ? a. 30 MHz b. 45 MHz c. 55 MHz d. 40 MHz ans: b For channel 1, transmit/receive frequency is a. 825.030/870.030 MHz b. 835.03/880.03 MHz c. 825.015/870.015 MHz d. 825.15/870.15 MHz ans: c The number of transmit/receive channels in the cellular system is a. 625 b. 645 c. 655 d. 666 ans: d The transmission range of cellular telephony is generally about a. 80 km b. 65 km c. 160 km d. 16 km ans: a When the message is transferred from one cell site transmitter to another cell site transmitter as the caller crosses a boundary _________ process takes place.
a. shifting b. hand off c. give off d. turn over ans: b What is the sensitivity of a cellular receiver? a. 20 dB b. 40 dB c. 50 dB d. 60 dB ans: c What a. ± b. ± c. ± d. ± ans:
is 15 30 12 75 c
the frequency deviation of the cellular telephone system? kHz kHz kHz kHz
Hailing channel is otherwise known as a. conversation channel b. calling channel c. signaling channel d. remote channel ans: b What is an Erlang? a. It is a unit of magnetic field intensity measured around a conductor b. It is the number of erroneous bits received per unit of time c. It is a unit of electrical energy radiated in space d. It is equal to the number of simultaneous calls originated during a specifi c hourly period ans: d All of the cell base stations are linked together by ______ which serves as th e central office and management node for the group. a. MTS b. IMTS c. MSTO d. MTSO ans: d Provides interface between the mobile telephone switching office and the mobil e units. a. Database b. Cell site c. Terrestrial link d. Radio transmitter ans: b A phone call over the cellular network requires a. simplex channels b. half duplex channels c. full duplex channels d. full/full duplex ans: c A method of expressing the amplitudes of complex non-periodic signals such as speech.
a. Volume b. Pitch c. Frequency d. Wavelength ans: a _________ is a signal returned to the talker after making one or more round tr ips between the talker and the listener. a. Singing b. Echo c. Jitter d. Crosstalk ans: b _________ is a voice operated device that insert a high loss in the opposite d irection of transmission of the talking party. a. Hybrid b. 2-wire circuit c. Echo suppressor d. VNL ans: c _________ is picking up of the same station at two nearby points on the receiv er dial. a. Double spotting b. Hot shot c. Image frequency d. Bail shot ans: a When one channel picks up the signal carried by another channel. a. Echo b. Crosstalk c. Party line d. Crosslink ans: b What type of connector arrangement wherein a customer may move to another loca tion and still retain the same telephone number. a. TPL b. Bridge c. TPS d. Party line ans: c It is an advantage of sidetone. a. Transmission efficiency is increased b. Speaker increase his voice resulting in a strengthened signal c. No dissipation of energy in the balancing network d. Assures the customer that the telephone is working ans: d Radio communications between points using a single share frequency. a. Simplex b. Full duplex c. Half-duplex d. Full/full duplex ans: c The transmission of information from multiple sources occurring on the same fa
cility but not at the same time. a. FDM b. TDM c. WDM d. CDM ans: b When human voice and music are transmitted, the type of communication employed is known as a. radiotelegraphy b. audio frequency c. wired radio d. radiotelephony ans: d Printed documents to be transmitted by fax are converted into a baseband elect ric signal by the process of a. copying b. scanning c. modulation d. light variation ans: b What is the most commonly used light sensor in a modem fax machine? a. Phototube b. Phototransistor c. Liquid-crystal display d. Charge couple device ans: d In FM fax, the frequencies for black and white are ____________ respectively. a. 1500 and 2300 Hz b. 2300 and 1500 Hz c. 1300 and 2400 Hz d. 1070 and 1270 Hz ans: a Which resolution produces the best quality fax? a. 96 lines per inch b. 150 lines per inch c. 200 lines per inch d. 400 lines per inch ans: d Group 2 fax uses which modulation? a. SSB b. FSK c. Vestigial sideband AM d. PSK ans: c The most widely used fax standard is a. Group 1 b. Group 2 c. Group 3 d. Group 4 ans: c Group 3 fax uses which modulation? a. QAM
b. FSK c. Vestigial sideband AM d. FM ans: a Most fax printers are of which type? a. Impact b. Thermal c. Electrosensitive d. Laser xerographic ans: b Facsimile standards are set by the a. FCC b. DOD c. CCITT d. IEEE ans: c What type of graphics are commonly transmitted by radio fax? a. Newspaper text b. Architectural drawings c. Cable movies d. Satellite weather photos ans: d What is the transmission speed of group 4 fax? a. 4800 baud b. 9600 baud c. 56 kbits/s d. 192 kbits/s ans: c What is the cause of insertion loss? a. Thermal noise that intermodulate with signal traveling on the same medium. b. A momentary disruption of signal due to power interruption c. A low level high frequency signal inserted into the original signal caused by thermal noise d. none of these ans: d __________ is the master control center for cellular telephone system. a. Cell site b. Mobile telephone switching office c. Central office d. Branch office ans: b Each cell site contains a a. repeater b. control computer c. direct link to a branch exchange d. touch-tone processor ans: a What is a trunk? a. The base of a communications tower. b. A telephone line connecting two central offices. c. A line connecting one telephone set to a PABX. d. Refers to the body of a tree.
ans: b Cellular telephones use which type of operation? a. Simplex b. Half-duplex c. Full-duplex d. Triplex ans: c What is the maximum frequency deviation of an FM cellular transmitter? a. 6 kHz b. 12 kHz c. 30 kHz d. 45 kHz ans: b Receive channel 22 is 870.66 MHz. Receive channel 23 is a. 870.36 MHz b. 870.63 MHz c. 870.96 MHz d. 870.69 MHz ans: d A transmit channel has a frequency of 837.6 MHz. The received channel frequenc y is a. 729.6 MHz b. 837.6 MHz c. 867.6 MHz d. 882.6 MHz ans: d A receive channel frequency is 872.4 MHz. To develop an 82.2 MHz IF, the frequ ency synthesizer must supply an LO signal of a. 790.2 MHz b. 827.4 MHz c. 954.6 MHz d. 967.44 MHz ans: c The output power of a cellular radio is controlled by the a. user or caller b. cell site c. called party d. MTSO ans: d When the signal from a mobile cellular unit drops below a certain level, what action occurs? a. The unit is "handed off" to a closer cell b. The call is terminated c. The MTSO increases power level d. The cell site switches antenna ans: a In a cellular radio, the duplexer is a a. ferrite isolator b. waveguide assembly c. part of TR/ATR tubes d. pair of sharp bandpass filters ans: d
On a telephone system, the loop is open during a. on-hook condition b. off-hook condition c. both A and B d. none of these ans: a For every button pressed on a touch-tone telephone, how many signals are trans mitted to the C.O.? a. Two VHF signals b. One VHF signal and one audio-frequency tone c. Two audio-frequency tones d. Three audible tones ans: c What is the traffic model about blocked calls clear condition specified blocki ng probability? a. Erlang B b. Erlang C c. Erlang D d. Poisson ans: a A touch-tone telephone generates how many different tones. a. 10 audio-frequency tones b. 8 audible tone frequencies c. 4 VHF signals d. 16 audio-frequency tones ans: b The base-to-mobile frequency assignment of a GSM system. a. 890 - 915 MHz b. 825 - 845 MHz c. 870 - 890 MHz d. 935 - 960 MHz ans: d A voice-grade channel is suitable for transmission of a. VHF signals b. UHF signals c. VHF and UHF signals d. signals with a frequency ranging from 300 to 3400 Hz ans: d What is the bandwidth of cellular CDMA system? a. 1.23 MHz b. 1.23 GHz c. 1.23 kHz d. 1.23 THz ans: a What is a communication link? a. It is a piece of wire that is connected to ground terminals of all communic ations equipment in one establishment. b. It is a channel or circuit intended to connect other channels or circuits. c. It is a cable connecting a transmitter to the antenna d. It refers to a radio link. ans: b -
Block calls held condition specified the held probability at a time period equ al to an average holding time. a. Erlang B b. Erlang C c. Erlang D d. Poisson ans: d What is an echo? a. A signal of the same amplitude but 180 degrees out of phase from the origin al signal and mixed with the original signal at the transmitter to produce a mor e intelligible output signal. b. A wave which has been reflected or otherwise returned with sufficient magni tude and delay for it to be perceptible in some manner as a wave distinct from t hat directly transmitted. c. The signal having a higher frequency than the original and transmitted back to earth by a passive satellite. d. A reflected signal. ans: b What is the system used by Personal Communication Network (PCN) a. TACS b. Modified GSM c. AMPS d. CDMA ans: b Termination refers to a. cutting both ends of a conductor b. disconnecting a line from a transmitter c. looking back impedance of a line with no load d. load connected to the output end of a transmission line ans: d The multiple access used by Digital European Cordless Telephone (DECT). a. CDMA b. FDMA c. TDMA d. CDMA/FDMA ans: c Blocked calls delay condition specified delay probability. a. Erlang B b. Erlang C c. Erlang D d. Poisson ans: b Status information provided by telephone signaling. a. Busy tone, dial tone and ringing b. Congestion and call charge data c. All of the above d. none of the above ans: c The modulation technique used by DECT. a. GFSK b. ASK c. QAM d. PSK
ans: a What is a four-wire circuit? a. is used between serving central offices for long-distance connections, with one pair being used for each direction of transmission. b. Is a circuit with three output terminals and one input terminal c. Is an oscillator that produces four different frequencies simultaneously d. A circuit consisting of four transmission lines. ans: a Cellular CDMA system uses what modulation method? a. GFSK b. ASK c. QAM d. BPSK ans: d PABX means a. Private All-purpose Broadcasting Exchange b. Private Automatic Branch Exchange c. Public Access Bi-directional Exchange d. Public Automatic Branch Exchange ans: b What is the voted cellular digital standard at TIA? a. Digital AMPS b. GSM c. CDMA d. TACS ans: a What is the number of channels for Band A and for Band B in Digital AMPS? a. 832 b. 416 c. 666 d. 888 ans: b The mobile-to-base frequency assignment for GSM system is a. 890 - 915 MHz b. 935 - 960 MHz c. 870 - 890 MHz d. 825 - 845 MHz ans: a The range (in miles) of a cellular CDMA system. a. 13 b. 30 c. 45 d. 20 ans: a In a cellular system, ____________ is used to measure the spectrum efficiency. a. radio efficiency b. diversity c. frequency reuse d. radio capacity ans: d -
Which of the following echo is completely out of control? a. Worst echo b. Reverberation c. Singing d. Feedback ans: c Which of the following devices increase the battery voltage on a loop and exte nds its signaling range? a. Loop extender b. VF repeater c. VF amplifier d. All of these ans: a Under ordinary circumstances, the CCITT recommends that the number of circuits in tandem must not exceed a. 9 b. 10 c. 11 d. 12 ans: d What is the system capacity of AMPS? a. 30,000 b. 60,000 c. 100,000 d. 120,000 ans: c NAM means a. Non Alternable Memory b. Number Allocation Module c. Numeric Assignment Module d. Numeric Access Module ans: c
