| 4. |
Design a 4-input priority encoder for the
inputs and outputs shown in the table below. Input D3, the most significant
bit, has the highest priority. |
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The valid output designated by V is set to 1
only when one or more of the inputs are equal to 1. If all inputs are 0, V is equal to 0
and the other two outputs of the circuit are not used. |
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(i) Complete the truth table |
[6] |
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(ii) Draw the K-map for A1 and A0 |
[4] |
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(iii) Show the simplified Boolean expression
for all 3 outputs |
[4] |
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(iv) Draw the logic diagram for the 4-input
priority encoder with the minimum number of gates |
[4] |
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(v) How does an ordinary encoder differ from a
priority encoder? |
[2] |