Description : sare the codes that represent alphabetic characters, punctuation marks and other special characters: a. Alphanumeric codes b. ASCII codes c. EBCDIC codes d. All of these
Last Answer : a. Alphanumeric codes
Description : The correctness and accuracy of the transmitted message content is A. verified by the modem B. communications system C. determined by the sender and receiver D. ensured by use of digital technique
Last Answer : C. determined by the sender and receiver
Description : What term is used to describe a spread spectrum communications system in which a very fast binary bit stream is used to shift the phase of an RF carrier? A. Frequency hopping B. Direct sequence C. Binary phase-shift keying D. Phase compandored spread spectrum
Last Answer : B. Direct sequence
Description : Binary communications systems are better because A. they can interface directly with the analog telephone network B. the components are simpler, less costly, and more reliable C. people think better in binary D. interstate calls are less costly
Last Answer : B. the components are simpler, less costly, and more reliable
Description : IP addresses are converted into (a) a binary string (b) alphanumeric string -Technology
Last Answer : (c) DNS translates domain names into their IP addresses and vice-versa.
Description : In facsimile transmission, a page is scanned and converted into a sequence of a. Binary sequence b. Ternary sequence c. black or white pixels d. alphanumeric sequence
Last Answer : c. black or white pixels
Description : Rules governing the transmission of digital information. A. Line protocol B. Isochronous C. Data communications D. Digital communications
Last Answer : B. Isochronous
Description : Highest frequency that can be used for skywave HF communications between two given points on earth. A. Gyro frequency B. Maximum usable frequency C. Critical frequency D. Virtual frequency
Last Answer : B. Maximum usable frequency
Description : A radio communications service use in radio regulation between specified fixed points provided primarily for the safety of air navigation and for the regular efficient and economical air transport ... operation service B. Space service C. Aeronautical mobile service D. Aeronautical fixed service
Last Answer : D. Aeronautical fixed service
Description : Who is responsible in the correctness and accuracy of transmitted information content over a data communication? A. The channel B. The transmitter and receiver C. The modem D. The bridge
Last Answer : B. The transmitter and receiver
Description : Assembly Language- 1) uses alphabetic codes in place of binary numbers used in machine language 2) is the easiest language to write programs 3) need not be translated into machine language
Last Answer : 1) uses alphabetic codes in place of binary numbers used in machine language
Description : Assembly Language 1 uses alphabetic codes in place of binary numbers used in machine language 2 is the easiest language to write programs 3 need not be translated into machine language 4 none of these
Last Answer : 1 uses alphabetic codes in place of binary numbers used in machine language
Description : What is meant by antenna gain? A. The final amplifier gain minus the transmission line losses (including any phasing lines present) B. The ratio of the amount of power produced by the antenna ... D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Last Answer : D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Description : The line control unit (LCU) operates on the data digital form. A. Data communications equipment (DCE) B. UART C. Modem D. Data terminal equipment (DTE)
Last Answer : D. Data terminal equipment (DTE)
Description : Noise always affects the signal in a communications systems at the ________. A. transmitter B. channel C. information source D. destination
Last Answer : B. channel
Description : What is the main purpose of a communications system? A. None of these B. To have a frequency assignment C. For modulation D. To provide an acceptable replica of the information at the destination
Last Answer : D. To provide an acceptable replica of the information at the destination
Description : Iridium satellites can provide data communications of up ____ bps data rate. A. 1200 B. 4800 C. 2400 D. 3840
Last Answer : C. 2400
Description : What satellite subsystem monitors onboard conditions such as temperature and battery voltage and transmits this data back to a ground station for analysis? A. Communications subsystem B. AKM C. TTC D. Transponder
Last Answer : C. TTC
Description : In telecommunications when we call data communications it means the transmission of________. A. Voice and video B. Voice C. Video D. Computer data
Last Answer : D. Computer data
Description : Which of the following is not a common microwave application? A. Radar B. Data transmission C. Space communications D. Mobile radio
Last Answer : D. Mobile radio
Description : The primary purpose of the data modem is to A. interface analog terminal equipment to analog communications channel B. interface digital terminal equipment to analog communications ... to digital communications channel D. interface digital terminal equipment to digital communications channel
Last Answer : B. interface digital terminal equipment to analog communications channel
Description : RS-232, RS-449, RS-530, V, 24 and X.21 are examples of ____________. A. standards for interfaces between modems and transmission facilities B. standards for various types of ... for interfaces between terminals and modems D. standards for end to end performance of data communications system
Last Answer : C. standards for interfaces between terminals and modems
Description : What numeric symbols are used in the binary number system? 58) A) 0 through 8 B) 0, 1, 2 C) 1, 2 D) 0, 1
Last Answer : D) 0, 1
Description : In radio signal emission designation, the fifth symbol means A. Details of signals B. Type of information transmitted C. Nature of multiplexing D. Nature of signal modulating the main carrier
Last Answer : C. Nature of multiplexing
Description : In radio regulation, the first symbol in the designation of radio emission is ______. A. Bandwidth B. Nature of signal(s) modulation the main carrier C. Type of modulation of the main carrier D. Type of information to be transmitted
Last Answer : C. Type of modulation of the main carrier
Description : The third symbol in the designation of radio emission under the ITU rules refers to A. Type of the modulation of the main carrier B. Bandwidth C. Nature of the signals modulating the main carrier D. Type of information to be transmitted
Last Answer : D. Type of information to be transmitted
Description : The first symbol in the designation of radio emission under the ITU rules to A. Nature of signals modulating the main carrier B. Type of information to be transmitted C. Bandwidth D. Type of modulation of the main carrier
Last Answer : D. Type of modulation of the main carrier
Description : What is the maximum theoretical data rate of the above problem if one transponder is used for binary transmission? A. 36 Mbps B. 72 Mbps C.18 Mbps D. 144 Mbps
Last Answer : B. 72 Mbps
Description : In data communication the transmission of binary signals will require _______. A. Same bandwidth as analog B. More bandwidth than analog C. Less bandwidth than analog D. Bigger cable diameter
Last Answer : B. More bandwidth than analog
Description : The main benefit of light-wave communications over microwaves or any other communications media is a. Lower cost b. Better security c. Wider bandwidth d. Freedom from interference
Last Answer : c. Wider bandwidth
Description : Which of the following is used as an optical receiver in fiber optics communications a. APD b. Tunnel diode c. Laser diode d. LED
Last Answer : a. APD
Description : Which of the following is used as an optical transmitter on the Fiber Optical Communications? a. APD b. LSA diode c. PIN diode d. LED
Last Answer : d. LED
Description : Is a non-coherent light source foe optical communications system. a. ILD b. LED c. APD d. PIN Diode
Last Answer : b. LED
Description : Which does not use vertical polarization antenna? A. AM Broadcasting B. FM Broadcasting C. Mobile Communications D. Satellite Communications
Last Answer : B. FM Broadcasting
Description : Which of the following is the most common application of satellite? A. Surveillance B. Military application C. Communications D. Newscasting
Last Answer : C. Communications
Description : What is the free space attenuation of a satellite communications system operating at 36,000 km above the earth at 5.0 GHz? A. 198 dB B. 202 dB C. 142 dB D. 138 dB
Last Answer : A. 198 dB
Description : The satellite communications channels in a transponder are defined by the A. LNA B. bandpass filter C. mixer D. input signals
Last Answer : B. bandpass filter
Description : The satellite subsystem that monitors and controls the satellite is the A. propulsion subsystem B. power subsystem C. communications subsystem D. telemetry, tracking, and command subsystem
Last Answer : D. telemetry, tracking, and command subsystem
Description : The key electronic component in a communications satellite is the A. telemetry equipment B. on-board computer C. command and control system D. transponder
Last Answer : D. transponder
Description : The main function of a communications satellite is a/ an A. repeater B. reflector C. beacon D. observation platform
Last Answer : A. repeater
Description : The frequency of Ku band for satellite communications. A. 6/4 GHz B. 14/11 GHz C. 12/14 GHz D. 4/8 GHz
Last Answer : B. 14/11 GHz
Description : Repeaters inside communications satellites are known as A. Trancievers B. Transponders C. Transducers D. TWT
Last Answer : B. Transponders
Description : Name one or more sources of noise bearing on electronic communications. A. Steam boiler B. Galaxies C. Internal combustion engine D. Both B and C
Last Answer : D. Both B and C
Description : A large emission of hydrogen from the sun that affects communications. A. Solar flare B. Cosmic disturbance C. Ballistic disturbance D. Solar noise
Last Answer : A. Solar flare
Description : Is the interference coming from other communications channels? A. Jitter B. Crosstalk C. RFI D. EMI
Last Answer : B. Crosstalk
Description : Which of the following frequencies is normally used for distress and safety communications? A. 4209.5 kHz B. 490 kHz C. 518 kHz D. 2174.5 kHz
Last Answer : D. 2174.5 kHz
Description : What is the common up-converter and down-converter IF for microwave communications? A. 60 MHz B. 80 MHz C. 120 MHz D. 70 MHz
Last Answer : D. 70 MHz
Description : How does spatial isolation technique in satellite communications avoid interference? A. Use of different polarity antennas B. Use of different types of antennas C. Employment of highly directional spot-beam antennas D. Use of low gain antennas
Last Answer : C. Employment of highly directional spot-beam antennas
Description : Which of the following is the basic component of a communications satellite receiver? A. On-board computer B. Reflector C. Telemetry D. Transponder
Last Answer : D. Transponder
Description : A radio communications link is to be established via the ionosphere. The maximum virtual height of the layer is 100 km at the midpoint of the path and the critical frequency is 2 MHz. The distance between stations is 600 ... optimum working frequency? A. 6.32 MHz B. 2.1 MHz C. 5.4 MHz D. 1.8 MHz
Last Answer : C. 5.4 MHz