: COE353 l H.W l C.h3


2009-12-24, 12:18 AM
:COE353 Homework Chapter 3
1.


A ____________ is a disturbance that propagates down a transmission medium to the other side, which reads it.
2. When a signal travels, this is called _____.
3. Changes in a signal during propagation are called, most generally, _______.
4. In binary 13 is 1101. What is 14 ? _________.
5. With N bits. How many choices can you represent ?
6. You need to represent 35 courses. How many bits will you need ?
7. How many bits does ASCII use to represent keyboard characters ?
8. Your computer screen has a resolution of 800 pixels horizontally and 600 pixels vertically. How many bytes will a JPEG screen image be?
9. What is the advantage of sending more bits per clock cycle with multistate digital signaling?
a. More bits can be sent per clock cycle.
b. There are fewer errors.
c. Both A and B.

10. Is it correct to call all binary transmission digital transmission?
a. Yes.
b. No.

11. Which of the following is true?
a. Binary signaling is always digital signaling.
b. Digital signaling is always binary signaling.
c. Both A and B.
d. Neither A nor B.

12. (If you read the box Digital Signaling.) In digital transmission, as the number of states increases, transmission speed _____.
a. increases
b. decreases
c. stays largely unchanged

13. (If you read the box Digital Signaling.) In digital transmission, as the number of states increases, error resistance _____.
a. increases
b. decreases
c. stays largely unchanged


14. (If you read the box Digital Signaling.) In digital transmission, every time you double the number of states, ___.
a. you can send one more bit per clock cycle
b. the number of bits per clock cycle increases by the square of its previous value
c. Neither A nor B


15. (If you read the box Digital Signaling.) The number of clock cycles a transmission system uses per second is called its ______.
a. bit rate
b. baud rate
c. Both of the above.
d. Neither A nor B

16. (If you read the box Digital Signaling.) The rate at which data is transmitted is the ______.
a. bit rate
b. baud rate
c. Both A and B
d. Neither A nor B


17. (If you read the box Digital Signaling.) If you have 10,000 clock cycles per second and transmit in binary, ________.
a. the bit rate is 10 kbps
b. the baud rate is 10 kbaud
c. Both A and B
d. Neither A nor B


18. In the UTP wiring used in LANs, how many wires are there in a cord?
a. 1.
b. 2.
c. 4.
d. 8.
e. 25.

19. In the UTP wiring used in LANs, how many wire pairs are there in a cord?
a. 1.
b. 2.
c. 4.
d. 8.
e. 25.


20. When a signal grows weaker as it travels, this is called _____. (Choose the most specific answer.)
a. a propagation effect
b. noise
c. interference
d. attenuation
e. All of the above.

21. In Ethernet, limiting UTP cord runs to 100 meters limits _____ to an acceptable level.
a. attenuation
b. noise errors
c. Both A and B

22. In most versions of Ethernet, what is the maximum cord length allowed by the standard?
a. 1.25 cm (a half inch).
b. 100 meters.
c. Both A and B.
d. There is no maximum length in the standard.

23. When a one pair in a UTP cord interferes with signals in other pairs, this is _____.
a. EMI
b. crosstalk interference
c. terminal crosstalk interference
d. internal noise

24. Serial transmission is transmission over a single wire pair.
a. True.
b. False.


25. The main benefit of parallel transmission over serial transmission is ______.
a. reliability
b. speed
c. Both A and B
d. Neither A nor B


26. Parallel transmission is transmission over _____.
a. four wire pairs
b. more than one wire pair



27. Which form of UTP can carry 10 Gbps signals 100 meters?
a. Cat 6.
b. Cat 6A.
c. Both A and B.
d. Neither A nor B.


28. Optical fiber uses _____ signaling. (Give the most specific answer.)
a. multiple-voltage-level
b. two-voltage-level
c. on/off
d. digital
e. All of the above.


29. Today, the main benefit of optical fiber compared with UTP is _____.
a. rugged construction
b. lower cost
c. the ability to transmit signals faster
d. the ability to span greater distances



30. Compared with UTP, optical fiber is _____ expensive to buy and install today.
a. less (when all costs of purchasing and installation are considered)
b. as
c. more

31. In optical fiber, light travels through the _____.
a. core
b. cladding
c. Neither A nor B


32. The ability to transmit in two directions simultaneously is _____.
a. parallel communication
b. full-duplex communication
c. Both A and B
d. Neither A nor B


33. The ability to transmit in two directions simultaneously is called parallel transmission.
a. True.
b. False.


34. A popular type of optical fiber connector is _____.
a. SC
b. ST
c. Both A and B
d. Neither A nor B



35. Optical fiber transmission usually is expressed in terms of _____.
a. frequency
b. wavelength
c. Both A and B about equally.

36. LANs normally use _____.
a. multimode fiber
b. single-mode fiber

37. Compared with single-mode fiber, multimode fiber has _____ core.
a. a wider
b. a narrower
c. the same width

38. Why is multimode fiber used instead of single-mode fiber for LAN transmission?
a. Lower cost.
b. Higher speed.
c. Longer propagation distance.
d. All of the above.

39. What is a typical core diameter for multimode fiber?
a. 50 microns.
b. 8.3 microns.
c. Both A and B.
d. Neither A nor B.

40. Single mode fiber has a core diameter of_____.
a. 8.3 microns
b. 62.5 microns
c. Either A or B

41. Single mode fiber distance is limited primarily by _____.
a. modal dispersion
b. absorptive attenuation
c. Both A and B about equally.

42. Multimode fiber distance is limited primarily by _____.
a. modal dispersion
b. attenuation
c. Both A and B about equally.





43. Wireless transmission usually is expressed in terms of _____.
a. frequency
b. wavelength
c. Both a. and b.

44. _____ antennas transmit about equally strongly in all directions.
a. Omnidirectional
b. Dish
c. Both A and B
d. Neither A nor B

45. Which of the following has faster attenuation with distance?
a. UTP.
b. Radio transmission.
c. Both A and B have about equally fast attenuation.

46. If the signal strength from an omnidirectional radio source is 8 milliwatts at 30 meters, how strong will it be at 90 meters?
a. 64 mW.
b. 8/3 mW.
c. 1 mW.
d. 8/9 mW.
e. None of the above.

47. _____ the physical arrangement of a networks computers, switches, routers, and transmission links.
a. Network architecture is
b. Network topology is
c. Network layout is
d. Physical layer standards are

48. Topology is a _____ layer concept.
a. physical
b. data link
c. Both A and B
d. Neither A nor B

49. Ethernet uses a(n) _____ topology.
a. point-to-point
b. extended star
c. mesh
d. ring
e. bus



50. Routers use a(n) _____ topology.
a. point-to-point
b. extended star
c. mesh
d. ring
e. bus





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