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MODD / Mr. Hansen |
Name:
_________________________ |
Test #1b
A calculator is permitted. Do not spend too much time
on any single problem. Clues to some problems that you cannot solve initially
may be found elsewhere in the test.
Part I: Essays (18 pts. each).
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1. |
Give 3 examples of analog
quantities or phenomena, and give 3 examples of digital quantities or
phenomena. For each of these 6 items, write a sentence to explain precisely
why it is analog (or digital). |
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2.(a) |
Sketch a circuit diagram
that captures the following logic (where the symbol Å indicates XOR): |
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(b) |
Use a truth table to prove
that the logic requested in (a) is not
equivalent to A + B + C. If you are stuck, you can purchase a hint for a
couple of points. |
Part II: Problems/Short Essays (10 pts. each). Show work if you desire partial credit.
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3. |
Perform the hex addition
BECCA + F0AB, and give your answer in hex. |
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4. |
In approximately what year
will computers be 2,000 times more powerful than they are today? |
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5. |
Audio for CDs is sampled at
44.1 KHz. Explain why a sampling rate of 10 KHz would be unacceptable. |
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6. |
Suppose that before
sampling an audio signal at 10 KHz (as in #5), we first run the signal
through a low-pass filter that strips out all signal components below 4.5
KHz. Would the results be acceptable now? Explain your answer. |
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7. |
Compute the S/N ratio for |
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(a) |
. . . a
process that performs A/D conversion with 20-bit samples. |
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(b) |
. . . a
process in which the signal power is at 50,000 watts when the noise is at 2
watts. |
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8. |
Give the term for the A/D
conversion process. Hint: It begins
with the letter Q. Then explain why this process always creates some noise. |
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9.(a) |
Briefly explain the difference between bit depth and pixel resolution in digital images. |
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(b) |
Compute the storage
requirement (in KB) for a 300 x 400 image that uses 24 bits per pixel. |