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 : The basic modulator and demodulator circuits in PSK are:
Last Answer : Balanced modulators
Description : In a synchronous modem, the digital-to-analog converter transmits signal to the a. equilizer b. modulator c. demodulator d. terminal e. none of aobve
Last Answer : equilizer
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 : What distinguishes digital radio systems from conventional analog communications system?
Last Answer : the nature of the modulating signal
Description : The modulated picture carrier wave includes the composite video signal as the:
Last Answer : Symmetric envelope of amplitude variations
Description : A 4.5-MHz signal which is equal to the difference between the picture and sound RF carrier frequencies in a 6-MHz TV channel.
Last Answer : Intercarrier frequencY
Description : The service are in standard AM broadcast is described as ______ if there is no fading of signal.
Last Answer : Primary
Description : The total bandwidth of an NTSC TV signal is:
Last Answer : . 6 MHz
Description : The most critical and difficult part of receiving a direct – sequence spread spectrum signal is :
Last Answer : Synchronism
Last Answer : 6 MHz
Description : To a conventional narrowband receiver, a spread spectrum signal appears to be
Last Answer : Noise
Description : The minimum optical power a light detector can receive and still produce a usable electrical output signal.
Last Answer : light sensitivity
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 : Rate of change of a signal on a transmission medium after encoding and modulation have occurred
Last Answer : baud rate
Description : Used for transmission of PCM encoded time – division multiplexed digital signal.
Last Answer : T carriers
Description : The signal from a satellite is normally aimed at a specific area called the ________
Last Answer : footprint
Description : When microwave energy is passed through a piece of ferrite in a magnetic field, another effect occurs. If the frequency of the microwave energy is much greater than the electron wobble frequency, the plane of polarization of the wavefront is rotated. This is known as
Last Answer : Faraday Rotation Effect
Description : Which circuit detects frequency modulated signal? A. Modulator B. Discriminator C. Demodulator D. Modem
Last Answer : B. Discriminator
Description : The term modem is a composite word that refers to the two functional entities that make up the device: asignal _______ and a signal _______. A) modulator; demodulator B) demodulator; modulator C) modern;demo D) none of the above
Last Answer : modulator; demodulator
Description : The result whenever the sampling rate is less than twice the highest audio frequency.
Last Answer : alias
Description : The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization ___
Last Answer : is horizontal
Description : It is the ratio of the power density radiated in a particular direction to the power density radiated to the same point by a reference antenna, assuming both antennas are radiating the same amount of power
Last Answer : directive gain
Description : The property of interchangeability for the transmitting and receiving operations is known as ____
Last Answer : reciprocity
Description : The fields surrounding the antenna do not collapse their energy back into the antenna but rather radiate it out in space
Last Answer : radiation field
Description : It is the ratio of the radiated to the reflected energy:
Last Answer : Radiation efficiency
Description : It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates
Last Answer : . Radiation resistance
Description : Plots of field strength or power density with respect to the value at a reference point.
Last Answer : relative radiation pattern
Description : The radiation pattern plotted in terms of electric field strength or power density
Last Answer : absolute radiation pattern
Description : The line bisecting the major lobe, or pointing from the center of the antenna in the direction of maximum radiation is called _____
Last Answer : line of shoot
Description : A special type of transmission line that consist of conducting metallic tube through which high frequency electromagnetic energy is propagated
Last Answer : waveguide
Description : If energy is applied at the geometrical center of antenna, the antenna is said to be ___
Last Answer : center-fed
Description : The radiation pattern of collinear and a broadside antenna is __
Last Answer : bidirectional
Description : Hertz antenna are predominantly used with frequencies above
Last Answer : 2MHz
Description : The point on the antenna where the transmission line is connected is called _____
Last Answer : feedpoint
Description : The discone antenna is
Last Answer : useful as a UHF receiving antenna
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 : ____ 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 : ______ are special-interest groups that quickly test, evaluate, and standardize new technologies
Last Answer : Forums
Description : _______ refers to the structure or format of the data, meaning the order in which they are presented.
Last Answer : Semantics
Description : ________ defines how a particular pattern to be interpreted, and what action is to be taken based on that interpretation.
Last Answer : syntax
Description : The effect of a large magnitude of the numerical aperture.
Last Answer : The amount of external light the fiber will accept is greater
Description : It is the figure of merit used to measure the magnitude of the acceptance angle.
Last Answer : numerical aperture
Description : It is a result of photons of light that are absorbed by the atoms of the glass core molecule
Last Answer : infrared absorption
Description : It is caused by valence electrons in the silica material from which the fiber are manufactured.
Last Answer : ultraviolet absorption
Description : It is analogous to power dissipation to copper cables, impurities in the fiber absorb the light and covert it to heaT
Last Answer : absorption loss
Description : The maximum angle in which external light rays may strike the air/glass interface and still propagate down the fiber.
Last Answer : Acceptance cone half-angle
Description : Laser light is very bright because it is:
Last Answer : coherent
Description : The process of moving from one energy level to another is called __
Last Answer : Absorption