Data Comm Chapter 3 Quiz

If each sample uses 16 bits and the number of samples taken each second is 8000, then the transmission speed on the circuit is?

need to find the answer****

A _____ is a FDM device that splits the physical circuit into three logical circuits (phone, upstream data, downstream data).

DSL modem

Digital transmission occurs when the signal sent over the transmission media constantly varies among an infinite number of states

False

In a multipoint circuit configuration, each computer has a dedicated circuit between itself and each of the other computers in the network

False

The amount of time it takes to switch between sending and receiving in half-duplex transmission is called the propagation delay

False

Microwave transmissions require a line of sight between any two points

True

One way to reduce quantizing errors is to increase the sampling rate of the analog signal

True

WDM is a version of FDM used in fiber-optic cables

True

The ability to transmit in both directions, but only in one direction at a time is an example of _____________ transmission

half-duplex

Microwave transmission:

is a type of high-frequency radio transmission

A coding scheme that uses 10 bits to represent each character is capable of representing _________ different characters

1024

When sending four bits at a time using frequency modulation, the number of different frequency levels needed is __

16

How many bits are required to sample an incoming signal 4000 times per second using 64 different amplitude levels?

6

When converting analog voice data to digital signals, Pulse Code Modulation typically samples the incoming voice signal ________ per second?

8000

If the highest freqency of a circuit is 10KHz and the lowest frequency is 900 Hz, the circuit's bandwidth is __

9.1 khz

_________ is one of the most commonly used coding schemes used in data transmission

ASCII

Which of the following is a key advantage of digital transmission?

it is more efficient than analog transmission, it is less prone to data transmission errors than analog, it is simpler to integrate video, voice and data on the same circuit

__ refers to changing the shape of an analog wave form in different ways to represent a 1 or a 0.

modulation

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.

need to find answer*

Which of the following is not a digital signalling technique?

need to find answer**

A(n) __________ circuit is another name for a multipoint configuration.

shared

Which of the following is a characteristic of electromagnetic waves that can be modulated to convert digitial data into analog signals?

amplitude

Another term for the weakening of a signal over distance is:

attenuation

Lempel-Ziv encoding enables modems to support ___

data compression

A codec converts an incoming digital signal to an analog signal for transmission over an analog network

false

Baud rate is the number of bits transmitted per second

false

One form of interference with satellite transmission is called raindrop attenuation in which the transmissions are absorbed by heavy rain

false

Which of the following is the most secure guided medium?

fiber optic cable

Which is not true about point-to-point circuits?

none; everything is true: called dedicated circuits, more expensive than multipoint, are used when the connected computers generate enough traffic to fill the capacity of the communications circuit

Which of the following is not an important factor to consider when selecting media to be used in a network?

prestige value of the type of media

_ is a widely used modulation technique that combines amplitude and phase modulation

quadrature amplitude modulation

__ 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.

quantizing error

The room that contains the cable termination points and the distribution frames is referred to as the:

telecommunication closet

The predominant method of transferring information internally in a computer is via parallel mode

true