CISM 3134-Ch.3
DSL modem
A _____ is a FDM device that splits the physical circuit into three logical circuits (phone, upstream data, downstream data).
false
A codec converts an incoming digital signal to an analog signal for transmission over an analog network.
1024
A coding scheme that uses 10 bits to represent each character is capable of representing _________ different characters.
shared
A(n) __________ circuit is another name for a multi point configuration.
attenutation
Another term for the weakening of a signal over distance is:
false
Baud rate is the number of bits transmitted per second
false
Digital transmission occurs when the signal sent over the transmission media constantly varies among an infinite number of states
6
How many bits are required to sample an incoming signal 4000 times per second using 64 different amplitude levels?
128 Kbps
If each sample uses 16 bits and the number of samples taken each second is 8000, then the transmission speed on the circuit is?
9.1 KHz
If the highest freqency of a circuit is 10KHz and the lowest frequency is 900 Hz, the circuit's bandwidth is
false
In a multipoint circuit configuration, each computer has a dedicated circuit between itself and each of the other computers in the network
data compression
Lempel-Ziv encoding enables modems to support
is a type of high-frequency radio transmission, is typically used for long-distance data transmission, does not require laying cable
Microwave transmission:
true
Microwave transmissions require a line of sight between any two points
true
One form of interference with satellite transmission is called raindrop attenuation in which the transmissions are absorbed by heavy rain.
true
One way to reduce quantizing errors is to increase the sampling rate of the analog signal.
half-duplex
The ability to transmit in both directions, but only in one direction at a time is an example of _______________ transmission.
false
The amount of time it takes to switch between sending and receiving in half-duplex transmission is called the propagation delay.
true
The predominant method of transferring information internally in a computer is via parallel mode.
telecommunications closet
The room that contains the cable termination points and the distribution frames is referred to as the:
true
WDM is a version of FDM used in fiber-optic cables.
8000
When converting analog voice data to digital signals, Pulse Code Modulation typically samples the incoming voice signal ________ per second?
sixteen
When sending four bits at a time using frequency modulation, the number of different frequency levels needed is
submerged transatlantic fiber optic cables
When you send an e-mail from the U.S. to the E.U., it is most likely to be transmitted from one continent to another through one of the ____ that connect America and Europe.
amplitude
Which of the following is a characteristic of electromagnetic waves that can be modulated to convert digitial data into analog signals?
fiber optic cable
Which of the following is the most secure guided medium?
It is more efficient than analog transmission, It is less prone to data transmission errors than analog transmission, It is simpler to integrate video, voice, and data on the same circuit
advantages of digital transmission
non-return-to-zero signalling, manchester encoding, unipolar signalling
digital signalling technique
transmission distance, type of network, cost
important factors to consider when selecting media to be used in a network
quadrature amplitude modulation
is a widely used modulation technique that combines amplitude and phase modulation
ASCII
is one of the most commonly used coding schemes used in data transmission
dedicated circuits
point-to-point circuits are called
modulation
refers to changing the shape of an analog wave form in different ways to represent a 1 or a 0
quantizing error
refers to the difference between the original analog data and the approximation of that data using the techniques for translating from analog data to digital signals.