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1. Which of these is best described by the term demodulation?

a) Analog to digital conversion in a modem receiver
b) Digital-to-analog conversion in a modem
c) Converting parallel data to serial data
d) None of the above

2. What are the steps of troubleshooting in correct order?

a) Visual inspection, Check power supply, Check inputs & outputs
b) Check power supply, Visual inspection, Check inputs & outputs
c) Visual inspection, Check inputs & outputs, Check power supply
d) None of the above

3. What is one disadvantage of serial data over parallel data?

a) The hardware to generate serial data is very expensive.
b) Serial data is much more prone to transmission errors than parallel.
c) The transmission speed of serial data is slower.
d) None of these

4. Before a terminal can transmit a message on a multidrop network, what must it first do?

a) Acquire the token
b) Transmit a request to send
c) Wait for the host to send it a poll message
d) None of the above

5. Which of these is a modulation process?

a) Analog to digital conversion in a modem receiver
b) Digital-to-analog conversion in a modem
c) Converting parallel data to serial data
d) None of the above

6. In troubleshooting a stage in an electronic device, where is the best place to check the power supply?

a) At the output terminal of the voltage regulator IC
b) Directly at the terminals of the device using the power
c) At the power supply buss line
d) None of the above

7. Parallel data is best described as:

a) All bits are sent at the same time.
b) One bit is sent at a time.
c) The data represented in analog form.
d) None of the above

8. A certain communication system has a bit-cell time of 1 mS and a BAUD of 500. How many bits does it encode per transition?

a) 2
b) 3
c) 4
d) None of the above

9. Which modulation method below changes the frequency of the carrier in order to represent the data?

a) FSK
b) ASK
c) PSK
d) None of these

10. A system transmits data at 19.2 KBPS, and has a signalling rate of 4800 BAUD. How many bits does it encode per transition?

a) 2
b) 3
c) 4
d) None of the above

11. What two factors determine the information carrying capacity of a communications channel?

a) Bandwidth and power gain
b) S/N ratio and bandwidth
c) Power gain and S/N ratio
d) None of the above

12. If the signalling rate is 600 BAUD and the constellation is as shown above, what will the actual data rate be?

a) 4800 BPS
b) 2400 BPS
c) 1200 BPS
d) None of these

13. Which of the below factors limits the number of bits per transition in practical communication systems?

a) Channel power gain
b) Channel bandwidth
c) Channel S/N ratio
d) None of the above

14. What type(s) of modulation are occuring in the figure above?

a) AM
b) FM
c) PM
d) Both A and C
e) None of the above

15. The rate at which changes are made to an analog carrier wave is called the _______?

a) BPS
b) CPS
c) BAUD
d) None of the above

16. The fundamental units of digital information flow are:

a) BAUD
b) CPS
c) BPS
d) None of the above

17. Which of these is a method of impressing information onto a carrier wave?

a) Amplitude modulation (AM)
b) Frequency modulation (FM)
c) Phase modulation (PM)
d) All of the above
e) None of the above

18. In a single-level modulation system, how many bits are represented for each transition?

a) 2
b) 3
c) 4
d) None of the above

19. How many bits are encoded per transition in the figure above?

a) 1
b) 2
c) 3
d) None of the above

20. In FSK, what property of the carrier is changed in order to represent the data?

a) Amplitude
b) Phase
c) Frequency
d) None of these

21. What is the acceptance cone angle for a fiber optic cable built with a core index N1=1.5, and a cladding index N2=1.45?

a) 30 degrees
b) 22.5 degrees
c) 11.25 degrees
d) None of these

22. Which of these fiber optics accepts light the easiest?

a) Acceptance cone angle = 45 degrees
b) NA = 0.707107
c) Both have an equal acceptance cone
d) Insufficient data to answer question

23. What is the meaning of the term 'numerical aperture'?

a) Ease of getting light into the fiber
b) Decibel loss per unit length in the fiber
c) Ease of splicing the fiber
d) None of the above

24. Why isn't modal dispersion a problem in single-mode fiber optics?

a) Light moves through these by reflection instead of refraction
b) Single-mode fiber optics can only be used for short-length runs
c) Only one light path is possible in a single-mode fiber
d) None of these

25. What is the numerical aperture (NA) for a fiber optic cable with a core index N1=1.6, and a cladding index N2=1.45?

a) 0.707
b) 0.451
c) 0.676
d) None of these

26. When a clock is sent with data, it is called ______ data.

a) Asynchronous
b) Synchronous
c) Digital
d) None of the above

27. Given that the parameters are 8,N,1 above, what hex data value is being sent?

a) $AB (0xAB)
b) $D3 (0xD3)
c) $D5 (0xD5)
d) None of the above

28. What type of data is sent without a clock signal?

a) Asynchronous
b) Synchronous
c) Analog
d) None of the above

29. In the figure above, the parameters are 8,N,2 and the bit time is 500 uS. How many characters can be sent per second?

a) 125
b) 136
c) 181.8
d) None of the above

30. In the figure above, the parameters are 8,N,1 and the bit time is 1 mS. How many characters can be sent per second?

a) 125
b) 111
c) 100
d) None of the above

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