Description : Involves compression in the transmitter after the input sample has been converted to a linear PCM code and then expansion in the receiver prior to PCM coding:
Last Answer : Digital companding
Description : The main advantage of DM over PCM is:
Last Answer : simple circuit
Description : In an amplitude modulated waveform, the amplitude of the sideband is
Last Answer : 1/2 carrier amplitude x modulation index
Description : A theory that establishes the minimum sampling rate that can be used for a given PCM systems.
Last Answer : Nyquist sampling theorem
Description : An integrated circuit that performs the PCM encoding and decoding functions
Last Answer : Codec
Description : A theory that establishes the minimum sampling rate that can be used for a given PCM systems
Description : The PCM code for each channel occupies a fixed time slot called:
Last Answer : Epoch
Description : Data rate at which serial PCM bits are clocked out of the PCM encoder onto the transmission line.
Last Answer : line speed
Description : In PCM, it converts the PAM sampled to parallel PCM codes
Last Answer : Analog-to-Digital converter
Description : The most common method used for sampling voice signals in PCM systems.
Last Answer : flat top sampling
Description : Numerical indication of how efficiently a PCM code is utilized
Last Answer : Coding efficiency
Description : Used for transmission of PCM encoded time – division multiplexed digital signal.
Last Answer : T carriers
Description : ____ is a virtual-circuit wide-area network that was designed in response to demands for a new type of WAN in the late 1980s and early 1990s.
Last Answer : . Frame Relay
Description : Sampling technique that when the tops of the sample pulses retain their natural shape during the sample interva
Last Answer : natural sampling
Description : n T1, it is equal to the reciprocal of the sample rate
Last Answer : Frame time
Description : Which of the following is not a typical FDM application?
Last Answer : Secure communications
Description : It is used to encode the minimum amount of speech information necessary to reproduce a perceptible message with a fewer bits that those needed by a conventional encoder/decoder
Last Answer : vocoders
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.
Description : It is proposed network designed by major telephone companies in conjunction with the ITU-T with the intent of providing worldwide telecommunications support for voice, data, video and facsimile information within the same networ
Last Answer : ISDN
Description : Ethernet is baseband transmission system designed by _____
Last Answer : Robert Metcalfe and David Boggs
Description : _______ is the cell relay protocol designed by the corresponding Forum and adopted by the ITU-T.
Last Answer : ATM
Description : How does lossy compression reduce the size of files? A. Through removing redundancies by grouping repeated data together. B. By removing some precision in data that humans would have difficulty to ... the amount of storage needed. D. By replacing blocks of data with more compact representations.
Last Answer : D. By replacing blocks of data with more compact representations.
Description : ______ finds the value of thesignal amplitudefor eachsample; ____ finds the change from the previous sample. A) DM; PCM B) PCM; DM C) DM; CM D) none of the abov
Last Answer : PCM; DM
Description : How speech is transmitted in a digital switching environment using PCM/TDM?
Last Answer : A digital carrier system is a communications system that uses digital pulses rather than analogue signals to encode information. Fig shows the block diagram for a digital carrier system. This digital ... to maintain frame and sample synchronization between the TDM transmitter and receiver.
Description : How long does it take to scan 2 picture elements when 400 are scanned in 50 microseconds?
Last Answer : 0.25 microsec
Description : An image uses 512 x 512 picture elements. Each element can take any of eight distinguishable levels. The maximum entropy in the above image will be:
Last Answer : 786432 bits
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 : Which type of fiber-optic cable is the most widely used?
Last Answer : multimode step-index
Description : Which type of fiber-optic cable has the least modal dispersion?
Last Answer : single-mode step index
Description : With which emission type is the capture effect more pronounced?
Last Answer : FM
Description : What is the type of mastergroup used for low – capacity microwave systems?
Last Answer : L600
Description : Type of bend that occurs as a result of differences in thermal contraction rates between the core and the cladding material.
Last Answer : Microbending
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 : 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