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Digital Audio Broadcasting system is the most significant advance in radio technology since the introduction of FM stereo. This is also known as
Eureka 147
For digital communications, a simple form of amplitude modulation is known as
on-off keying
PAM signals are multiplexed using
FET
Phase reversal keying is also known as
Phase shift keying
The technique that uses the BPSK vector relationship to generate an output with logical 0's and 1's determined by comparing the phase of two successive data bits is
differential phase shift keying
A special digital modulation technique that achieves high data rates in limited-bandwidth channels is called
QAM
The information sources modulate the same carrier after it has been separated into two carrier signals are at 90 degrees out of phase with each other
QUAM
The major difficulty faced by delta modulators
slope overload
FSK systems are much superior to two-tone amplitude modulation systems with respect to
ionospheric fading characteristics
The NRZ digital signal-encoding format has a ___ component in the waveform
DC
Using an oscilloscope to display overlayed received data bits that provide information on noise, jitter, and linearity is called
eye pattern
The type of radio transmission that uses pseudorandomly switched transmissions is known as
spread spectrum
Pseudorandom implies a sequence that can be ___ but has the properties of randomness
recreated
Circuit for digitizing voice at a low data rate by using knowledge of the way in which voice sounds are produced
vocoder
In the telephone system, the customer's telephone directory numbering is from 000 to 999, what is the capacity of the system
1000 lines
The first computer-controlled central office switching system used in PSTN
No. 1 ESS
The most versatile and popular crossbar switch was
#5XB
Designed and built the first transmitter and receiver of the telephone set
Antonio Meucci
Fax was invented by
Alexander Bain
Class of switching office which is the local exchange where subscriber loops terminated and received dial tone
Class 5
In telecommunications, the acronym NAM stands for
Numeric Assignment Module
Refers to the installation and use of optical fiber cable directly to the curbs near homes or any business environment as a replacement for plain old telephone service
FTTC
PCM, PWM, PAM, PPM. Quantizing error occurs in
PCM
Why is companding used in PCM
To protect small signals from quantizing distortion
PCM system which uses a single bit PCM code to achieve digital transmission of analog signals
delta modulation
With SPADE DAMA satellite system, there are ___ PCM-encoded voice band channels
900
Modulation which combines encoding and modulation to reduce the probability of error
TCM
A classification of telephone system using PCM and TDM
T1
The AT&T T1 lines use
8-bit PCM code with 24 voice channels
In TDM, the sampling rate of T1 and DS1
8000 bps
How many bits are there in each frame of DS-1 signal using TDM
193
In TDM, how many bits are there in a T1 frame
193
How many samples are there in a T1 frame of TDM system
24
The frame time for T1 digital carrier in a time domain multiplexing system
125 microsec
How many matergroup consists of a jumbo group
6
Bandwidth of an FDM system U600 mastergroup
2520 kHz
In FDM, L600 mastergroup has a bandwidth of
2728 kHz
Baseband frequency of an L600 standard FDM is
60 to 2728 kHz
Baseband frequency of a basic FDM super group
312 to 552 kHz
In standard FDM, the basic group's low band frequency is
60 to 2788 kHz
DIV, DVD, DTV, DAVID. One of the following is not a primary type of Hybrid data used to combine digitally encoded signal with FDM signal and transmit them as one composite baseband signal
DVD
A technology which multiplexes multiple optical carrier signals on a single optical fiber by using different wavelengths of laser light to carry different signals
wavelength-division multiplexing or wavelength-discrete multiplexing
The ground wire in a USB cable is
Brown
In digital communications system, firewire can convert data together up to ___ peripherals
63
PPM and PWM are superior to PAM systems in
noise characteristics
A procedure that decides which device has permission to transmit at a given time is called
line control
In a sample and hold (S/H) circuit, the time that it must hold the sampled voltage is
acquisition time
A single LSI chip containing both the ADC and DAC circuitry
codec
Is the ratio of the largest possible magnitude to the smalles possible magnitude that can be decoded by the digital-to-analog converter (DAC) in PCM systems
Dynamic Range
A modulation technique that makes use of wavelet transformations to represent the data being transmitted
fractal modulation AND wavelet modulation
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