Evaluation 2

Question 1

If there is no noise, how many signal levels would be needed to achieve the channel capacity of 8 Mbps? (Use the Nyquist formular)

Answer 1

16 signal levels

Question 2

What method is used to transmit and receive independent signals in a fixed time slot?

Answer 2

TDM (Time Division Multiplexing)

Question 3

What modulation scheme is used to transmit 4 bits per symbol in quadrature amplitude modulation?

Answer 3

QAM-16

Question 4

What is the channel capacity if the bandwidth is 1000 Hz and there are 8 signal levels? (Use the Nyquist formula)

A. 5000 bps
B. 6000 bps
C. 7000 bps
D. 8000 bps

Answer 4

6000

Question 5

What is the oldest and still most common transmission media?

A. Twisted pair
B. Fiber Cables
C. Coaxial Cables
D. Power Lines

Answer 5

Twisted pair

Question 6

A _________________ consists of a stiff copper wire as the core, surrounded by an insulating material. The insulator is encased by a cylindrical conductor, often as a closely woven braided mesh.

A. Twisted pair
B. Fiber Cable
C. Coaxial Cable
D. Power Line

Answer 6

Coaxial Cable

Question 7

______________________ uses a code sequence to spread the data signal over a wider frequency band. It is widely used commercially as a spectrally efficient way to let multiple signals share the same frequency band.

A. Direct Sequence Spread Spectrum
B. Code Division Multiple Access
C. Ultra Wide Band
D. Frequency Division Multiplexing

Answer 7

Direct Sequence Spread Spectrum

Question 8

_________________ forms the basis of 3G mobile phone networks and is also used in GPS (Global Positioning System). Even without different codes, direct sequence spread spectrum, like frequency hopping spread spectrum, can tolerate narrowband interference and multipath fading because only a fraction of the desired signal is lost.

A. Direct Sequence Spread Spectrum
B. Code Division Multiple Access
C. Ultra Wide Band
D. Frequency Division Multiplexing

Answer 8

Code division multiple access

Question 9

__________ sends a series of rapid pulses, varying their positions to communicate information. The rapid transitions lead to a signal that is spread thinly over a very wide frequency band.

A. Direct Sequence Spread Spectrum
B. Code Division Multiple Access
C. Ultra Wide Band
D. Frequency Division Multiplexing

Answer 9

Ultra wide band

Question 10

The most straightforward form of digital modulation is to use a positive voltage to represent a 1 and a negative voltage to represent a 0. For an optical fiber, the presence of light might represent a 1 and the absence of light might represent a 0. What is this modulation called?

A. Bits
B. Bipolar
C. Manchester
D. Non-Return to Zero

Answer 10

Non-return to zero