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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. The term poll means:

a) A notification of a message waiting
b) An error has been detected on a network.
c) An invitation to send
d) None of the above

3. 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

4. When we say that a device operates full duplex, what do we mean?

a) It can only communicate in one direction.
b) It can communicate in both directions, but only one at a time.
c) It can communicate in two directions at one time.
d) None of the above

5. Which of these best describes serial data?

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

6. Who or what acts as the controller or "boss" in a multidrop network?

a) The first terminal on the network
b) The system administrator
c) The host computer
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. The fundamental units of digital information flow are:

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

9. 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

10. 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

11. A modulator has an input data rate of 2400 BPS and encodes three bits per transition. Under these conditions, it uses up 1000 Hz of bandwidth. What will happen to the bandwidth if the data rate is reduced to 1200 BPS (and everything else stays the same)?

a) The bandwidth will remain exactly the same
b) The bandwidth will double
c) The bandwidth will become 750 Hz
d) None of the above

12. A certain system has 16 modulation states and has a signalling rate of 600 BAUD. What will the resulting data rate be?

a) 1200 BPS
b) 2400 BPS
c) 4800 BPS
d) None of the above

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. If a certain modulator produces a change in the carrier every 1 mS, what is the resulting signalling rate?

a) 500 BAUD
b) 1000 BAUD
c) 2000 BAUD
d) None of the above

15. A certain system has 8 modulation states and has an input data rate of 2400 BPS. What will the resulting signalling rate be?

a) 1200 BAUD
b) 2400 BAUD
c) 800 BAUD
d) None of the above

16. The data rate into a modulator is 1200 BPS, and its constellation is shown above. What will the signalling rate be?

a) 600 BAUD
b) 300 BAUD
c) 150 BAUD
d) None of these

17. 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

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. 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

21. What is the speed of light in a material with an index of refraction of 2.0?

a) 150,000,000 m/s
b) 200,000,000 m/s
c) 300,000,000 m/s
d) None of these

22. What is the primary effect of dispersion in a fiber optic cable?

a) Decreases the available signal at the receiver
b) Decreases the available bandwidth
c) Sharpens the rising and falling edges of data waveforms
d) None of these

23. 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

24. What mechanism keeps light inside of a fiber optic cable?

a) Refraction
b) Diffraction
c) Reflection
d) None of the above

25. What optical property of a material describes the velocity of light within it, relative to the speed of light in free-space?

a) Loss per unit length
b) Numerical aperture
c) Index of refraction
d) None of these

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

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

27. 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

28. In the above figure, 8 data bits, 1 stop bit, and a parity bit are being sent. What type of parity is in use?

a) Odd
b) Even
c) Can't tell from information given

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

a) $F3 (0xF3)
b) $A5 (0xA5)
c) $AF (0xAF)
d) None of the above

30. 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

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