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 : The sinusoidal carrier is pulsed so that one of the binary states is represented by a carrier while the other is represented by its absence. A. FSK B. ASK C. PSK D. QAM
Last Answer : B. ASK
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 : Digital modulation technique used in modems. A. ASK B. PSK C. FSK D. All of these
Last Answer : B. PSK
Description : _______ uses twocarriers, onein-phase andthe otherquadrature. A) ASK B) PSK C) FSK D) QAM
Last Answer : QAM
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 : Inan HFC network, the downstream data are modulated using the _______ modulation technique. A) PSK B) QAM C) PCM D) ASK
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 baseband signal modulation? A. RF carrier B. Video System C. Audio signal D. Binary coded pulses
Last Answer : A. RF carrier
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 : Which of the following is not a digital-to-analogconversion? A) ASK B) PSK C) FSK D) AM
Last Answer : AM
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 : Type of modulation used in TV broadcast visual transmitter. A. Pulse modulation B. DSBFC C. Vestigial sideband D. SSBFC
Last Answer : C. Vestigial sideband
Description : Which of the following systems is not used in radio detection and ranging? A. Frequency shift B. Frequency modulation C. Pulse radar D. Amplitude modulation
Last Answer : D. Amplitude modulation
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 : ECE Board Exam March 1996 One type of pulse communications system uses pulse that appear as a group, and which vary in number according to the loudness of the voice. This type of ... A. pulse duration modulation B. pulse amplitude modulation C. pulse code modulation D. pulse position modulation
Last Answer : A. pulse duration modulation
Description : ECE Board Exam March 1996 The modulation system used for telegraphy is A. frequency-shift keying B. two-tone modulation C. pulse-code modulation D. single-tone modulation
Last Answer : A. frequency-shift keying
Description : If digitaldata rateof 9600 bps is encoded using 8-level phaseshift keying (PSK) method, the modulation rate is A. 1200 bands B. 3200 bands C. 4800 bands D. 9600 bands E. None of the above
Last Answer : 3200 bands
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 : Digital transmission provides a higher level of signal quality than analog transmission because A. repeaters regenerate digital pulses and remove distorstion B. digital signals are easier to sample than ... and cannot easily be distorted D. analog signals are continuous and not easily distorted.
Last Answer : A. repeaters regenerate digital pulses and remove distorstion
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 : IS-95 uses which modulation technique? a) GMSK b) BPSK c) QAM d) AFSK
Last Answer : b) BPSK
Description : What is a pulse-width modulation (PWM) signal in Arduino?
Last Answer : A PWM signal in Arduino is a digital signal that varies the width of the pulse to simulate an analog signal.
Description : A technique used by codes to convert an analog signal into a digital bit stream is known as A) Pulse code modulation B) Pulse stretcher C) Query processing D) Queue management
Last Answer : Answer : A
Description : A pulse modulation technique as the width of a constant amplitude pulse is varied proportional to the amplitude of the analog signal at the time the signal is sampled.
Last Answer : PWM, PLM, PDM
Description : A technique used by codes to convert an analog signal into a digital bit stream is known as a. Pulse code modulation b. Pulse stretcher c. Query processing d. Queue management
Last Answer : a. Pulse code modulation
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
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 : 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 : If the percentage modulation of an AM amplifier is 88% and the modulating signal is 1 volt, the carrier has an amplitude of _______________. A. 1.14 volts B. 0.88 volt C. 1.88 volts D. 0.12 volt
Last Answer : A. 1.14 volts
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 : 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 : If the bit rate for an FSK signal is1200 bps, thebaud rate is ________. A) 300 B) 400 C) 600 D) 1200
Last Answer : 1200
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 : Which of the production is included in foodgrains production ? (A) Cereal (Rice & Wheat) crops, only (B) Pulse crops, only (C) Coarse cereal crops, only(D) All cereals (Rice & Wheat), pulses and coarse cereal crops
Last Answer : (D) All cereals (Rice & Wheat), pulses and coarse cereal crops
Description : Which digital data encoding method records a digital one as a positive pulse and a digital (zero) as a negative pulse and returns the tape to neutral between pulses?
Last Answer : Return-to-zero (RZ) encoding.
Description : why equalizing pulses are needed. Draw the vertical synchronizing pulse structure.
Last Answer : The ½ line difference just prior to the start of serrated vertical pulse does not affect the horizontal deflection synchronization but it does affect the vertical synchronization and the interlaced scanning. The ... the vertical sync pulse to occur at the correct time after every field.
Description : One of the following is not among the advantages of series modulation A. No transformer B. Suppressed white noise C. Simple D. Modulates any frequency
Last Answer : B. Suppressed white noise
Description : Referred to as an average power from the radio transmitter supplied to the antenna transmission line taken during one radio frequency cycle under no modulation. A. Carrier power B. Rated power C. Peak envelop power D. Mean power
Last Answer : A. Carrier power
Description : Average power of a radio transmitter supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation. A. Peak envelop power B. Rated power C. Carrier power D. Mean power
Last Answer : C. Carrier power
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 : The first laser emitted a. Pulses of 694 nm red light b. A continuous red beam c. Pulses of white light from a helical flashlamp d. Spontaneous emission
Last Answer : a. Pulses of 694 nm red light