Description : Inan HFC network, the downstream data are modulated using the _______ modulation technique. A) PSK B) QAM C) PCM D) ASK
Last Answer : QAM
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 : 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 : In IEEE 802.11, _______ isan optionalaccess method that can be implemented inan infrastructure network (not in an ad hocnetwork). A) DCF B) PCF C) either (a) or (b) D) neither (a) nor (b)
Last Answer : PCF
Description : The technique in which a congested node stops receiving data from the immediate upstream node or nodes is called as _______ A. Admission policy B. Backpressure C. Forward signaling D. Backward signaling
Last Answer : B. Backpressure
Description : Which modulation technique is used by GSM? a) GMSK b) BPSK c) QPSK d) GFSK
Last Answer : a) GMSK
Description : The HFC network uses _______ cable. A) twisted-pair B) coaxial C) fiber-optic D) acombination of (b) and (c)
Last Answer : fiber-optic
Description : Thestandard for datatransmission over an HFC network is called _______. A) MCNS B) DOCSIS C) CMTS D) ADSL
Last Answer : DOCSIS
Description : _______ uses twocarriers, onein-phase andthe otherquadrature. A) ASK B) PSK C) FSK D) QAM
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 : 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 : IS-95 uses which modulation technique? a) GMSK b) BPSK c) QAM d) AFSK
Last Answer : b) BPSK
Description : The first step in PCM is ________. A) quantization B) modulation C) sampling D) none of the above
Last Answer : sampling
Description : What modulation is normally used with digital data? A. AM B. FM C. SSB D. QPSK
Last Answer : D. QPSK
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 : The secondgeneration of cable networks is called a(n) _________ network. A) HFC B) HCF C) CFH D) none of the above
Last Answer : HFC
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 : 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 : 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 : _______ is suitable for businesses that require comparable upstream and downstream data rates. A) VDSL B) ADSL C) SDSL D) (a) and (b)
Last Answer : SDSL
Description : The most common technique to change an analog signal to digitaldata is called __________. A) PAL B) PCM C) sampling D) none of the abov
Last Answer : PCM
Description : What type of modulation is used on voice and video signals? A. AM B. FM C. SSB D. QPSK
Last Answer : B. FM
Description : PCM is an example of _______ conversion. A) digital-to-digital B) digital-to-analog C) analog-to-analog D) analog-to-digital
Last Answer : analog-to-digital
Description : The constellation diagram of QPSK has ______ dots. A) 2 B) 1 C) 4 D) none of the above
Last Answer : 4
Description : How many carrier frequencies are used in QPSK? A) 2 B) 1 C) 0 D) none of the above
Last Answer : 2
Description : If the baudrate is400 for a QPSK signal, thebit rate is ________ bps. A) 100 B) 400 C) 800 D) 1600
Last Answer : 800
Description : A _______ message tells an upstream router to start sending multicast messages for a specific groupthrough aspecific router. A) weed B) graft C) prune D) none of the above
Last Answer : graft
Description : A _______ message tells an upstream router to stop sending multicast messages for a specific group through aspecific router. A) weed B) graft C) prune D) none of the above
Last Answer : prune
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 : A traditional cable TV network transmits signals ______. A) upstream B) downstream C) upstream and downstream D) none of the above
Last Answer : downstream
Description : The constellation diagram of16-QAM has ______ dots. A) 4 B) 16 C) 8 D) none of the above
Last Answer : 16
Description : Which of the following is not an analog-to-analog conversion? A) AM B) PM C) FM D) QAM
Description : In________, the phase of thecarrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant. A) ASK B) PSK C) FSK D) QAM
Last Answer : PSK
Description : If the baudrate fora 64-QAM signal is 2000, what is the bit rate? A) 300 B) 400 C) 1000 D) 12000
Last Answer : 12000
Description : If the bit rate for a16-QAM signal is 4000 bps, what is the baudrate? A) 300 B) 400 C) 1000 D) 1200
Last Answer : 1000
Description : In QAM,both ________ of acarrier frequencyare varied. A) frequencyand amplitude B) phase andfrequency C) amplitudeand phase D) none of the above
Last Answer : amplitudeand phase
Description : In a fiber-optic cable, the signal is propagatedalong theinner core by _______. A) reflection B) refraction C) modulation D) none of the above
Last Answer : reflection
Description : _______ is designed to be usedin wirelessapplications in which stations must be ableto sharethe medium without interception by an eavesdropperand without beingsubject tojamming from a malicious intruder. A) Spread spectrum B) Multiplexing C) Modulation D) None of the above
Last Answer : Spread spectrum
Description : The sharing of a medium and its link by two or more devices is called _______. A) modulation B) encoding C) line discipline D) multiplexing
Last Answer : multiplexing
Description : The largest portionof the bandwidth for ADSLcarries_______. A) voice communication B) upstream data C) downstream data D) control data
Last Answer : downstream data
Description : ECE Board Exam March 1996 Which of the following pulse modulation systems is analog? A. Delta B. Differential PCM C. PWM D. PCM
Last Answer : C. PWM
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 : 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 : 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 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 : In frequency modulation, amplitude of modulated wave is A. positive B. negative C. constant D. zero
Last Answer : constant
Description : Which edges of the pulse can be modulated in pulse duration modulation?
Last Answer : Either, or both at the same time.
Description : The amplifiers following the modulated stage in a low level modulation AM system be (A) linear amplifier (B) harmonic generators (C) class C power amplifiers (D) class untuned amplifiers
Last Answer : The amplifiers following the modulated stage in a low level modulation AM system be class C power amplifiers