Description : In_________, the frequencyof the carrier signal is varied to representdata. Both peak amplitudeand phase remain constant. A) ASK B) PSK C) FSK D) QAM
Last Answer : FSK
Description : In________, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remainconstant. A) ASK B) PSK C) FSK D) QAM
Last Answer : ASK
Description : Modulation in which no signal is present between pulses A. Pulse modulation B. QAM C. PSK D. FSK
Last Answer : A. Pulse modulation
Description : _______ uses twocarriers, onein-phase andthe otherquadrature. A) ASK B) PSK C) FSK D) QAM
Last Answer : QAM
Description : Quadrature amplitude modulation(QAM) isa combination of ___________. A) ASK and FSK B) ASK and PSK C) PSK and FSK D) none of the above
Last Answer : ASK and PSK
Description : ASK, PSK, FSK,and QAM are examples of________conversion. A) digital-to-digital B) digital-to-analog C) analog-to-analog D) analog-to-digital
Last Answer : digital-to-analog
Description : DMT is a modulation technique that combineselements of _______ and _______. A) FDM; TDM B) QDM; QAM C) FDM; QAM D) PSK; FSK
Last Answer : FDM; QAM
Description : Digital modulation technique used in modems. A. ASK B. PSK C. FSK D. All of these
Last Answer : B. PSK
Description : In_______, the peakamplitude of one signal level is 0; the other is thesame as the amplitude of the carrier frequency. A) PSK B) OOK C) FSK D) none of the above
Last Answer : OOK
Description : Which of the following is not a digital-to-analogconversion? A) ASK B) PSK C) FSK D) AM
Last Answer : AM
Description : Inan HFC network, the downstream data are modulated using the _______ modulation technique. A) PSK B) QAM C) PCM D) ASK
Description : Compare binary ASK, FSK &PSK modulation techniques
Last Answer : Sr. No Parameter Binary ASK Binary FSK Binary PSK 1 Variable Characteristic Amplitude Frequency Phase 2 Maximum bandwidth(Hz) 2fb 5 fb /3 2fb 3 ... 1200 bits/sec Suitable for high bit rates 8 Detection method Envelope Envelope Coherent
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 : Which is the proper measurement of average power emitted by a pulsed laser? a. Energy x time b. Pulse energy x repetition rate c. Pulse energy / repetition rate d. Peak power x pulse length
Last Answer : b. Pulse energy x repetition rate
Description : Used for time division multiplexing. A. Frequency modulation B. Pulsed modulation C. SSB D. Amplitude modulation
Last Answer : B. Pulsed modulation
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 : A coherent binary phase shift keyed BPSK transmitter operates at a bit rate of 20 Mbps with a carrier to noise ratio C/N of 8.8dB. Find Eb/No. A. 73 dB B. 62.4 dB C. 81.8 dB D. 8.8 dB
Last Answer : D. 8.8 dB
Description : Which of the following is not a baseband signal modulation? A. RF carrier B. Video System C. Audio signal D. Binary coded pulses
Last Answer : A. RF carrier
Description : The transformer signal coding method for T1 carrier is A. Binary B. NRZ C. Manchester D. Bipolar
Last Answer : D. Bipolar
Description : Write the expression for FSK modulation.
Last Answer : Pvf=f2-f1/k0
Description : Define FSK modulation.
Last Answer : FSK is a type of frequency modulation ,in which the binary data or code is transmitted by means of a carrier frequency that is shifted between two fixed frequency namely mark(logic1) and space frequency(logic 0).
Description : The modulation technique used by GSM cellular system A. Phase shift keying B. Frequency shift keying C. Gaussian minimum shift keying D. QAM
Last Answer : C. Gaussian minimum shift keying
Description : Inan HFC network, the upstream data are modulated using the _______ modulation technique. A) QAM B) QPSK C) PCM D) ASK
Last Answer : QPSK
Description : What synchronization is provided so that the start and end of message is identified? A. Carrier B. Character C. Bit D. Clock
Last Answer : B. Character
Description : What does the noise weighting curve shows? A. Noise signals measured with a 144 handset B. Power levels of noise found in carrier systems C. The interfering effect of other frequencies in a voice ... a reference frequency of one kilohertz D. Interfering effects of signals compared with a 3-kHz tone
Last Answer : C. The interfering effect of other frequencies in a voice channel compared with a reference frequency of one kilohertz
Description : Type of emission produced by one of the early radio transmitter in trains of damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in radio telegraph and having sidebands on its carrier. A. Digital emission B. Key emission C. Cycle emission D. Spark emission
Last Answer : D. Spark emission
Description : The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction. A. Peak envelope power B. ERP C. Rated power D. Carrier power’
Last Answer : B. ERP
Description : Modulation means A. Varying of information B. Utilization of a single transmission channel to carry multiple signals C. Varying of some parameters of a carrier such as its amplitude to transmit information D. Transmit pulses in DC form on a copper wire
Last Answer : C. Varying of some parameters of a carrier such as its amplitude to transmit information
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 : What digital carrier transmits a digital signal at 274.176 Mbps? A. T1 B. T3 C. T2 D. T4
Last Answer : D. T4
Description : How many sidebands are present in the J3E mode? A. Two sidebands and a carrier B. One upper sideband C. One lower sideband D. Two carriers and one sideband
Last Answer : B. One upper sideband
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 t-carrier system, t3 has a bit rate of A. 560.160 Mbps B. 44.376 Mbps C. 44.736 Mbps D. 560.106 Mbps
Last Answer : C. 44.736 Mbps
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 : How far is the visual carrier from the lowest frequency in the spectrum of a monochrome TV broadcast channel following the NTSC standard? A. 1.5 MHz B. 1.25 MHz C. 4.5 MHz D. 0.25 MHz
Last Answer : B. 1.25 MHz
Description : What is the emission designation of a single sideband reduced carrier signal? A. H3E B. J3E C. R3E D. B8E
Last Answer : C. R3E
Description : What is the channel number of an FM station with a carrier frequency of 99.5 MHz? A. 256 B. 258 C. 257 D. 259
Last Answer : B. 258
Description : In the North American TDM system, what is the transmission rate in Mbps of T3 carrier system? A. 44.736 B. 6.312 C. 3.152 D. 274.176
Last Answer : A. 44.736
Description : ____ system transmits frequency-division-multiplexed voice band signals over a coaxial cable for distances up to 4000 miles. A. T carrier B. X carrier C. L carrier D. F carrier
Last Answer : C. L carrier
Description : What carrier system multiplexes 96 voice band channels into a single 6.312 Mbps data signal? A. T1 carrier system B. T2 carrier system C. T1C carrier system D. T3 carrier system
Last Answer : B. T2 carrier system
Description : What satellite system parameter represents the quality of a satellite or an earth station receiver? A. Gain-to-Equivalent Noise Temperature Ratio (G/Te) B. Energy of Bit-to-Noise Density Ratio (Eb/No) C. Carrier-to-Noise Density Ratio (C/No) D. Bit energy
Last Answer : A. Gain-to-Equivalent Noise Temperature Ratio (G/Te)
Description : What is the carrier frequency of supergroup 10? A. 2724 kHz B. 2356 kHz C. 2108 kHz D. 3100 kHz
Last Answer : D. 3100 kHz
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 term used to describe a spread spectrum communications system where the center frequency if a conventional carrier is altered many time per second in accordance with a pseudo ... hopping B. Direct sequence C. Time-domain frequency modulation D. Frequency compandored spread spectrum
Last Answer : A. Frequency hopping
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 : What is meant by the term deviation ratio? A. The ratio of the audio modulating frequency to the center carrier frequency. B. The ratio of the maximum carrier frequency deviation to the highest ... . D. The ratio of the highest audio modulating frequency to the average audio modulating frequency.
Last Answer : B. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.
Description : Determine the terrain sensitivity loss for a 4-GHz carrier that is propagating over a very dry, mountainous area. A. -1.25 dB B. -3.05 dB C. -2.01 dB D. -5.01 dB
Last Answer : A. -1.25 dB
Description : In regulation of public telecommunications carrier such as in the evaluation of new entrant, the following consideration shall be given emphasis to _______. A. Legal, technical and citizenship B. ... and kind of service C. Citizenship, capacity and financial D. Technical, legal and financial
Last Answer : D. Technical, legal and financial
Description : What is meant by the term deviation ratio? A. The ratio of the carrier center frequency to the audio modulating frequency B. The ratio of the highest audio modulating frequency to the ... audio modulation frequency D. The ratio of the audio modulating frequency to the center carrier frequency
Last Answer : C. The ratio of the maximum carrier frequency deviation to the highest audio modulation frequency
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