Description : In a synchronous modem, the digital-to-analog converter transmits signal to the a. equilizer b. modulator c. demodulator d. terminal e. none of aobve
Last Answer : equilizer
Description : The term modem is a composite word that refers to the two functional entities that make up the device: asignal _______ and a signal _______. A) modulator; demodulator B) demodulator; modulator C) modern;demo D) none of the above
Last Answer : modulator; demodulator
Description : The name “modem” is derived from (1) modern demarkator (2) modulator demand (3) modern demodulator (4) modulator demodulator
Last Answer : modulator demodulator
Description : What is a frequency discriminator? A. A circuit for filtering two closely adjacent signals B. A circuit for detecting FM signals C. An FM generator D. An automatic bandswitching circuit.
Last Answer : B. A circuit for detecting FM signals
Description : _________ detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. A. Horn antenna B. LNA C. Satellite receiver D. Satellite dish
Last Answer : B. LNA
Description : What type of transmission is radiated from an aircraft’s radio altimeter antenna? A. An amplitude modulated continuous wave B. A pulse position modulated UHF signal C. A differential phase shift keyed UHF signal D. A frequency modulated continuous wave
Last Answer : D. A frequency modulated continuous wave
Description : What is meant by the term modulation index? A. The processor index. B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. C. The FM signal-to-noise ratio. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.
Last Answer : B. The ratio between the deviation of a frequency modulated signal and the modulating frequency.
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 : A particular circuit that rids FM of noise A. Detector B. Discriminator C. Phase Shifter D. Limiter
Last Answer : D. Limiter
Description : In an FM receiver, which circuit removes amplitude variations? A. Exciter B. Mixer C. Discriminator D. Limiter
Description : In computing, how is a modulator-demodulator more commonly known?
Last Answer : Modem
Description : The basic modulator and demodulator circuits in PSK are:
Last Answer : Balanced modulators
Description : Which circuit contributes most of the noise in a receiver? A. IF amplifier B. Demodulator C. AF amplifier D. Mixer
Last Answer : D. Mixer
Description : A 1 Mhz carrier is amplitude modulated by a pure 200-Hz audio test tone. Which of the following combinations of frequencies represent the total content of the AM signal? A. 1 MHz and 200 Hz B. 1 MHz and 1000.2 kHz C. 999.8 kHz, 1000 kHz, and 1000.2 kHz D. 999.8 kHz and 1000.2 kHz
Last Answer : C. 999.8 kHz, 1000 kHz, and 1000.2 kHz
Description : What is the first symbol of a radio signal transmission having an amplitude modulated signal carrier, double side band? A. C B. B C. H D. A
Last Answer : D. A
Description : What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. Interference to adjacent channel B. Higher fidelity C. Increase noise D. Higher audio signal
Last Answer : A. Interference to adjacent channel
Description : The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the ... . Reference audio output B. None of these C. Audio frequency response D. Residual noise level
Last Answer : D. Residual noise level
Description : What do you call a circuit that controls the magnetron output? A. Inverter B. Impeller C. Modulator D. Converter
Last Answer : C. Modulator
Description : The conversion of digital signal into analog for purposes of transmitting into the telephone line is done through ______. A. ISDN B. Radio C. RS232C D. Modem
Last Answer : D. Modem
Description : What is a device that detects both vertically and horizontally polarized signals simultaneously? A. Orthomode transducer B. Crystal detector C. Optoisolator D. Isomode detector
Last Answer : A. Orthomode transducer
Description : ______ is a device that detects both vertically and horizontally polarized signals simultaneously. A. Crystal B. Orthomode transducer C. Light transducer D. Optoisolator
Last Answer : B. Orthomode transducer
Description : Amplitude of modulated wave is in phase with A. output B. system C. frequency D. signal
Last Answer : signal
Description : If frequency of modulated wave is less than frequency of carrier wave, then input signal is A. negative B. positive C. zero D. infinite
Last Answer : negative
Description : The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, thesignal modulates another carrier frequency. A) FDM B) DSSS C) FHSS D) TDM
Last Answer : FHSS
Description : In_____ transmission, the frequency of the carrier signal is modulated to follow the changing voltage level (amplitude)of the modulating signal. The peak amplitude and phase of the carrier signal remainconstant,but as ... of thecarrier changes correspondingly. A) AM B) PM C) FM D) none of the above
Last Answer : FM
Description : Carrier is A. One or more conductors that serve as a common connection for a related group of devices B. a continuous frequency capableof being modulated or impressed witha second signal C. ... that provides a data communications service among stations attached tothe network E. None of the above
Last Answer : a continuous frequency capableof being modulated or impressed witha second signa
Description : Contention is A. One or more conductors that serve as a common connection for a related group of devices B. a continuous frequency capableof being modulated or impressed witha second signal C. ... that provides a data communications service among stations attached tothe network E. None of the above
Last Answer : the condition whentwo or more stations attempt to use the same channel at the same time
Description : A 4 GHz carrier is amplitude modulated by a low-pass signal of maximum cut off frequency 1 MHz. lf this signal is to be ideally sampled, the minimum sampling frequency should be nearly
Last Answer : A 4 GHz carrier is amplitude modulated by a low-pass signal of maximum cut off frequency 1 MHz. lf this signal is to be ideally sampled, the minimum sampling frequency should be nearly 4 Ghz
Description : The local loop of the telephone system is understood to be A. a single piece of wire connecting the subscriber's telephone set to another telephone set in an adjacent room B. a two-wire or four- ... a facsimile machine to a computer D. a group of wires connecting a telephone set to a modem
Last Answer : B. a two-wire or four-wire communication circuit between the customer’s premise and central office
Description : Which of the following is not usually a part of a transponder are defined by the A. LNA B. Mixer C. Modulator D. HPA
Description : Combination of modulator, channel and detector. A. Transceiver B. Discrete channel C. T/R channel D. Transponder
Last Answer : B. Discrete channel
Description : The output of a balanced modulator is ____________. A. LSB and USB B. LSB C. USB D. Carrier
Last Answer : A. LSB and USB
Description : What type of tank circuit is used in the Foster-Seeley discriminator?
Last Answer : A double-tuned tank circuit.
Description : A 1000W carrier is amplitude modulated to a depth of 85%. Calculate the total power of the modulated wave? A. 1361.25 W B. 680.62 W C. 1425 W D. 712.5 W
Last Answer : A. 1361.25 W
Description : A modulation which does not follow the sine wave pattern, it produces undesirable harmonics such as spurious emission A. 0% modulated B. Over-modulated C. Unmodulated D. 100% modulated
Last Answer : B. Over-modulated
Description : Refers to the first symbol in an emission designation with an amplitude modulated main carrier represented by letter H. A. Single sideband suppressed carrier B. Double sideband full carrier C. Independent sideband D. Double sideband
Last Answer : B. Double sideband full carrier
Description : In amplitude modulation technique the unmodulated carrier is referred to as having ______. A. 100% modulation B. 0% modulation C. 50% modulated D. Over modulated
Last Answer : B. 0% modulation
Description : A transmitter supplies 8 kW to the antenna when it is unmodulated, determine the total radiated power when modulated at 90%. A. 5 kW B. 20 kW C. 15 kW D. 8.36 kW
Last Answer : D. 8.36 kW
Description : What is emission F3F? A. Facsimile B. Modulated CW C. RTTY D. Television
Last Answer : D. Television
Description : Modulation in which the modulated wave is always present. A. Carrier modulation B. Front-end C. Continuous modulation D. Log-periodic modulation
Last Answer : C. Continuous modulation
Description : The series of periodically recurrent pulses is modulated in amplitude by the corresponding instantaneous samples. A. PFM B. PWM C. PDM D. PAM
Last Answer : D. PAM
Description : What do you call the energy that was not radiated into space or completely transmitted? A. Incident waves B. Captured waves C. Standing waves D. Modulated waves
Last Answer : C. Standing waves
Description : Energy that has neither been radiated into space nor completely transmitted. A. Captured waves B. Incident waves C. Standing waves D. Modulated waves
Description : The best frequency demodulator is the:
Last Answer : PLL discriminato
Description : A quorum sensing system A- .detects a signal from the external environment B- B.senses a compound produced by the bacterium itself C- consists of a sensor component that phosphorylates a regulatory protein D- .controls the activity of ribosomes directly
Last Answer : B.senses a compound produced by the bacterium itself
Description : Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? A. dc B. low C. intermediate D. high
Last Answer : D. high
Description : Unwanted radio signal on assigned frequency. A. Splatter B. RFI C. Noise D. EMI
Last Answer : C. Noise
Description : What determines the ability of radar to determine the bearing to a target? A. Speed of light B. Speed of target C. Antenna directivity D. Frequency of signal
Last Answer : C. Antenna directivity
Description : What is the deviation ratio for an FM-phone signal having a maximum frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of 3kHz? A. 60 B. 0.16 C. 0.6 D. 1.66
Last Answer : D. 1.66