CIS 454/ 554, Fall 2000
Quiz 1
Close Book & Close Notes !!!!
Name ------
Student ID ------
A. (10) Multiple choice questions (10 points):
For each statement, circle the best answer.
1)When a signal propagates along a transmission line its amplitude decreases (called signal attenuation). Which one of the following we need to insert at intervals along the cable to restore the received signal to its original level? ?
a)Amplifiers
b)Repeaters
c)All of the above
d)None of the above
2) What telecommunications hardware is needed to convert digital signals to analog signals?
a) Mouse
b) Device driver
c) Modem
d) Slot
3) Which one of the following is system software?
a) Microsoft excel
b) Microsoft Windows
c) Microsoft Paint
d) Microsoft Word
4)Which of the following is not a function of an operating system?
a) Controls basic input and output
b) Allocates system resources
c) Manages storage space
d) Carries out a specific task for the user
5) Which of the following is considered as an input device?
a) Monitor
b) Printer
c) Mouse
d) Plotter
6) What are the four essential components of data communication system?
a) Hard disk, floppy disk, tape drive, and CD
b) RAM, ROM, virtual memory, and CMOS
c) Sender, receiver, a channel, and a protocol
d) DOS, UNIX, Windows, Mac, Lotus notes
7)Operating system is a/an:
a) System software
b) Application software
c) Hard ware
d) None of the above
8)What is a megabyte?
a) 10 kilobytes?
b) About a million bytes
c) One-half a gigabyte
d) About a million bits
9)Which of the following devices translates images such as pictures or documents into digital form for processing?
a) Keyboard
b) Computer mouse
c) Digital scanner
d) Sensors
10)High SNR indicates:
a)Good quality signal
b)Low quality signal
c)A high power signal relative to the noise level
d)a) and c)
B.Draw diagrams to represent the transmitted signal for data (010010) and show the following effects:
( 1 * 4 = 4 points)
- Attenuation effect
- Limited bandwidth effect
- Delay distortion effect
C.Write down 4 lines about any transmission medium (Advantages, disadvantage, max. transmission rate, use). (4 points)
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D.Assuming that a PSTN has a bandwidth of 3000 Hz and a typical signal-to-noise power ratio of 20 db, determine the maximum theoretical information rate that can be achieved. (2 points)
Required formulae:
SNR = 10 log 10 (S/N)
C = W log 2 (1 + S/N)
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