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MODD / Mr. Hansen |
Name:
_________________________ |
Test on Unit 0x40 (Topics 0x29 and 0x41-0x4F, omitting
0x48 and 0x4E for now)
Time limit: 32 minutes (48 minutes for extended
time). A calculator is permitted.
Each question is worth 5 points. Your name is worth 3 points.
Instructions for Part I: For multiple choice questions, write the capital
letter of the best choice in the
blank provided. For fill-in problems, write the word or phrase that best fits in
the space provided.
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___ 1. |
Dr. Octagon is a Radio
Shack Model 100 laptop computer from the year 1983. Dr. Octagon, a cousin of
Smokey, contains a 300 bps modem that sends approximately how many bytes per
minute? |
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(A) 1,000 |
(D) 10,000 |
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___ 2. |
Dr. Octagon’s modem uses a
modulation of a telephone signal that sends a binary 0 or 1 with each pulse
(“symbol”) that is sent. The baud rate is . . . |
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(A) 150 |
(D) 800 |
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___ 3. |
Newer modems send symbols
that encode multiple bits into each symbol that is sent over the phone line.
The bit rate of a somewhat more modern 1200 baud modem, where each symbol
represents a hex digit, is . . . |
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(A) 1200 · (bits per
symbol) = 3600 bps |
(D) 1200 · (bits per
symbol) = 19,200 bps |
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___ 4. |
POTS stands for |
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(A) plain old telephone
service |
(D) pulse operated tracking
service |
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___ 5. |
Which of these would
probably have the best RLE compression ratio? |
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(A) a typical text file |
(D) a high-resolution
bitmap, 3 bytes/pixel |
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___ 6. |
Phil Katz developed . . . |
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(A) LHARC |
(D) lung cancer |
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___ 7. |
What factors affect the
quality of digital image transmission? |
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(A) resolution (number of
horizontal and vertical pixels) |
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___ 8. |
Why is the ITU so
important? |
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(A) It isn’t. The
organization is now called CCITT. |
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(B) Without the ITU, fax and
modem protocols would be in a state of greater confusion. |
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(C) Without the ITU,
digital bitstreams could not be sent over telephone
lines. |
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(D) Without the ITU, analog
TV and analog radio transmission would not be possible. |
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(E) Without the ITU,
electrical power could not be transmitted across great distances. |
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___ 9. |
MP3 compression suppresses
sounds that are inaudible because they immediately follow loud sounds on an
original master recording. This type of psychoacoustic compression effect is
called . . . |
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(A) pitch masking |
(D) subsonic masking |
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___10. |
The most common MP3 bit rate
gives an overall compression ratio, compared to uncompressed WAV format, of
roughly . . . |
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(A) 3:1 |
(D) 50:1 |
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Instructions for Part II: Write a free response for each question. The answers
can be quite short.
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11, 12. |
Explain how conventional
Morse Code, as used by old-time telegraph operators and some amateur radio operators
to this day, incorporates features of both Huffman coding and tokenization. |
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13. |
What are the instructions
shown on the board called? Hint: The
word starts with a “P.” |
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14-16. |
Use the instructions shown
on the board to decode the RLE bitmap defined on the board. |
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17. |
State the hex number
(0x0D0AB77C) in a big-endian representation. |
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18. |
State the same hex number
(0x0D0AB77C) in a little-endian representation. |
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19. |
List several advantages of data
compression. |
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20. |
Is a ZIP file compressible?
Why or why not? Explain briefly |