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 : Pulse – amplitude modulation signals are multiplexed by using
Last Answer : FET switches
Description : In an AM transmitter with 100% modulation, the voltage of the final RF stage will be
Last Answer : approximately four times the DC supply voltage
Description : Pulse width modulation may be generated:
Last Answer : with a monostable multivibrator
Description : It is the ratio of the transmission bit rate to the minimum bandwidth required for a particular modulation scheme
Last Answer : Bandwidth efficiency, Information density, or Spectral efficiency
Description : Which is not purpose of modulation?
Last Answer : Increase in signal power
Description : Rate of change of a signal on a transmission medium after encoding and modulation have occurred
Last Answer : baud rate
Description : A modulation technique where data rates in excess of 56 kbps can be achieved over telephone circuits
Last Answer : Trellis Code Modulation
Description : In an amplitude modulated waveform, the amplitude of the sideband is
Last Answer : 1/2 carrier amplitude x modulation index
Description : It is the ratio of the largest possible magnitude to the smallest possible magnitude that can be decoded by the digital-to-analog converter in the receiver.
Last Answer : Dynamic range
Description : In_____ transmission, thecarrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal. A) AM B) PM C) FM D) none of the above
Last Answer : AM
Description : Bits can be sent over guided and unguided media as analog signal by ___________ a. digital modulation b. amplitude modulation c. frequency modulation d. phase modulation
Last Answer : a. digital modulation
Description : A virtual circuit which is logically equivalent to a two-point dedicated private-line circuit except slower
Last Answer : Permanent Virtual Circuit
Description : It is the same with directive gain except that the total power fed to the antenna is used and the antenna efficiency is taken into account.
Last Answer : power gain
Description : It is logically equivalent to making telephone call through the DDD network except no direct end-to-end connection is made
Last Answer : Virtual call
Description : The service are in standard AM broadcast is described as ______ if there is no fading of signal.
Last Answer : Primary
Description : It involves converting standard logic levels to a form more suitable to telephone transmission lines
Last Answer : igital line encoding
Description : _______ is a standard developed by ANSI for fiber-optic networks.
Last Answer : SONET
Description : It is a large scale integration chip designed for use in telecommunication industry for private branch exchanges, central office switches, digital handsets and digital echo suppressors.
Last Answer : Codec
Description : What distinguishes digital radio systems from conventional analog communications system?
Last Answer : the nature of the modulating signal
Description : It is a system where the digital signals are placed directly on the coaxial cable.
Last Answer : Baseband
Description : Used for transmission of PCM encoded time – division multiplexed digital signal.
Last Answer : T carriers
Description : n T1, it is equal to the reciprocal of the sample rate
Last Answer : Frame time
Description : A(n) ________function creates a message digest out of a message.
Last Answer : hash
Description : They wrote a paper describing how it was possible to use stimulated emission for amplifying light waves (laser) as well as microwaves (maser).
Last Answer : Charles Townes and Arthur Schawlow
Description : The phase relationship between signaling elements for BPSK is the optimum signaling format and occurs only when two binary signal levels are allowed and when one signal is the exact negative of the other
Last Answer : Antipodal signaling
Description : ____ is a process-to-process protocol that adds only port addresses, checksum error control, and length information to the data from the upper layer.
Last Answer : UDP
Description : In a ______ handoff, a mobile station only communicates with one base station
Last Answer : hard
Description : What is the full form of 'AM' regarding radio broadcasting? (1) Amplitude Movement (2) Anywhere Movement (3) Amplitude Matching (4) Amplitude Modulation
Last Answer : (4) Amplitude Modulation Explanation: AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still ... frequency. It then amplifies changes in the signal voltage to drive a loudspeaker or earphones.
Description : In modulation technique, which of the following is referred to audible pitch? A. Width B. Frequency C. Harmonic D. Amplitude
Last Answer : B. 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 : 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 : 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 : Used for time division multiplexing. A. Frequency modulation B. Pulsed modulation C. SSB D. Amplitude modulation
Last Answer : B. Pulsed modulation
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 : 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 : 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 : 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 : In frequency modulation, amplitude of modulated wave is A. positive B. negative C. constant D. zero
Last Answer : constant
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 : 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 : what is angle and amplitude modulation? what is noise in modulation?
Last Answer : Ans- modulation means change. to send a message of low frequency to a far distance we use a carrier of high frequency to carry the message. while transfering we change some parameters of ... is an unwanted signal which enter in signal while transfering a signal and makes the signal distorted.
Description : What, if any, noise susceptibility advantage exists for pulse-amplitude modulation over analog amplitude modulation?
Last Answer : Both are susceptible to noise and interference
Description : With a single modulating tone, what is the amplitude of the sideband frequencies at 100-percent modulation?
Last Answer : One-half the amplitude of the carrier.
Description : What is amplitude modulation?
Last Answer : Any method of modulating an electromagnetic carrier frequency by varying its amplitude in accordance with the intelligence.
Description : Describe amplitude shift keying (ASK) modulation with suitable circuit diagram.
Last Answer : Explanation:- ASK MODULATOR: The process where a binary information signal directly modulates the amplitude of an analog carrier. The digital signal is used to switch the carrier between amplitude levels is ... Block diagram of ASK Transmitter / ASK modulator:- Waveforms:-
Description : What is the full form of ‘AM’ regarding radio broadcasting? (1) Amplitude Movement (2) Anywhere Movement (3) Amplitude Matching (4) Amplitude Modulation
Last Answer : Amplitude Modulation
Description : In amplitude modulation AM, if modulation index is more than 100% then: (1) Power of the wave increases. (2) Efficiency of transmission increases. (3) The wave gets distorted. (4) Bandwidth increases
Last Answer : In amplitude modulation AM, if modulation index is more than 100% then: The wave gets distorted.
Description : Amplitude modulation is used for broadcasting because (A) it is move noise immune than other modulation systems (B) compared with other systems it requires less transmitting power (C) ... receiver complexity (D) no other modulation system can provide the necessary bandwidth for high fidelity.
Last Answer : Amplitude modulation is used for broadcasting because its use avoids receiver complexity