Description : What type of modulation depends on the carrier-wave phase shift?
Last Answer : Phase.
Description : Variation in amplitude or frequency of carrier wave is called A. amplitude modulation B. frequency modulation C. modulation D. bandwidth
Last Answer : modulation
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 : What characteristic of a transistor is varied in a semiconductor-reactance modulator?
Last Answer : Collector-to-emitter capacitance.
Description : Give two reasons why the value of the normalized frequency (V) is varied in single mode stepindex fibers?
Last Answer : To increase performance and reduce losses caused by bending and splicing.
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 : Three audio waves with 100,200 and 300 volts amplitude respectively, simultaneously modulate a 450 volts carrier. What is the total percent of modulation of the AM wave? A. 69 % B. 115.5 % C. 50% D. 83%
Last Answer : D. 83%
Description : If the carrier of a 100 percent modulation modulated AM wave is suppressed, the percentage power saving will be (A) 50.55 (B) 15.55 (C) 10.66 (D) 66.66
Last Answer : If the carrier of a 100 percent modulation modulated AM wave is suppressed, the percentage power saving will be 66.66
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 : 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 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 : This is referred to a product of simultaneous frequency and amplitude modulation or a carrier frequency variation which produces unwanted distortion. A. Absorption modulation B. Simultaneous modulation C. Dynamic instability D. Series modulation
Last Answer : C. Dynamic instability
Description : It is an average power of a radio transmitter supplied to the antenna transmission line taken during a long sufficient interval of time and compared with the lowest frequency encountered in the modulation ... operating conditions. A. Carrier power B. Rated power C. Mean power D. Peak envelop power
Last Answer : C. Mean power
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 : Which determines the number of sideband components of FM? A. Modulation frequency B. Modulation index C. Carrier frequency D. All of these
Last Answer : B. Modulation index
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 : To ensure the accuracy of a transmission, what is the minimum number of times a modulating wave should be sampled in pulse modulation?
Last Answer : 2.5 times the highest modulating frequency.
Description : Name the modulation system in which the frequency alternates between two discrete values in response to the opening and closing of a key?
Last Answer : . Frequency-shift keying.
Description : What is pulse-frequency modulation?
Last Answer : A method of pulse modulation in which a modulating wave is used to frequency modulate a pulse-generating circuit
Description : How can field strength be varied in a practical dc generator?
Last Answer : By varying the input voltage to the field coils
Description : In frequency modulation, amplitude of modulated wave is A. positive B. negative C. constant D. zero
Last Answer : constant
Description : The ideal radar spectrum has what relationship to the carrier frequency?
Last Answer : Symmetrical above and below the carrier frequency.
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 : What is the WAVELENGTH of the carrier wave, in meters, of a radio station which is broadcasting at a frequency of 100 megahertz?
Last Answer : ANSWER: 3 METERS
Description : What characteristic is determined by the time required for a voltage wave to travel from the input end of an artificial transmission line to the output end and back again?
Last Answer : Pulse width
Last Answer : Pulse width.
Description : For 100% modulation, power in each sideband is ________ of that of carrier? a) 50% b) 70% c) 60% d) 25%
Last Answer : Ans: D
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 : 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 : An AM transmitter is rated 100W at 100% modulation. How much power required for the carrier? A. 33.33 W B. 66.66 W C. 83.33 W D. 100 W
Last Answer : B. 66.66 W
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 : 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 : At 100% modulation, the sum fo the effective voltages in both sidebands is equal to ______% of the unmodulated carrier voltage. A. 50 B. 71 C. 100 D. 25
Last Answer : B. 71
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 : 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 : The carrier swing necessary to provide 80% modulation in the FM broadcasting band is __________. A. 150 kHz B. 120 kHz C. 60 kHz D. 75 kHz
Last Answer : B. 120 kHz
Description : ECE Board Exam March 1996 The letter-number designation B8E is a form of modulation also known as ___________. A. pilot carrier system B. independent sideband emission C. lincomplex D. vestigial sideband transmission
Last Answer : B. independent sideband emission
Description : The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is A) 50 W B) 66 W C) 68 W D) 70 W
Last Answer : The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is 66 W
Description : If the radiated power of AM transmitter is 10 KW, the power in the carrier for modulation index of 0.6 is nearly: (1) 8.24 KW (2) 9.26 KW (3) 8.47 KW (4) 9.6 KW
Last Answer : If the radiated power of AM transmitter is 10 KW, the power in the carrier for modulation index of 0.6 is nearly: 8.47 KW.
Description : The speed of a squirrel-cage, multi-speed, induction motor, as used aboard ship, is varied by changing the __________. A. number of connected poles in the stator B. frequency to the motor C. excitation voltage D. resistance of the rotor circuit
Last Answer : Answer: A
Description : The speed of a synchronous motor is varied by _____________. A. interchanging any two of the three live leads B. changing the voltage of the system C. changing the input frequency D. increasing the field excitation
Last Answer : Answer: C
Description : An AC circuit has capacitance arranged in series. If the line voltage remains constant, the capacitive reactance value can be varied by changing the _____________. A. line frequency B. resistance C. number of commutating poles D. number of interpoles
Description : The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding
Last Answer : Answer: B
Description : How output frequency is varied in case of a thyristor?
Last Answer : The output frequency is varied by varying the turn off time of the thyristors in the inverter circuit, i.e. the delay angle of the thyristors is varied.
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 : In swept-frequency testing the impedance of a transmission line, what electrical characteristic is actually being measured?
Last Answer : Swr on the transmission line.
Description : What is the ripple frequency of a full-wave rectifier with an input frequency of 60 Hz?
Last Answer : 120 hertz.