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State truth table of 3 bit Gray to Binary conversion then design it using 3:8 decoder and additional gates.
1 Answer
| written 4.6 years ago by |
Truth table:
| Decimal | Gray Code input | Binary output | ||||
|---|---|---|---|---|---|---|
| G2 | G1 | G0 | B2 | B1 | B0 | |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1 | 0 | 0 | 1 | 0 | 0 | 1 |
| 2 | 0 | 1 | 1 | 0 | 1 | 0 |
| 3 | 0 | 1 | 0 | 0 | 1 | 1 |
| 4 | 1 | 1 | 0 | 1 | 0 | 0 |
| 5 | 1 | 1 | 1 | 1 | 0 | 1 |
| 6 | 1 | 0 | 1 | 1 | 1 | 0 |
| 7 | 1 | 0 | 0 | 1 | 1 | 1 |
Output expression
$B_2=0_4+0_5+0_6+0_7 \\[2ex] B_1=0_3+0_4+0_6+0_7 \\[2ex] B_0=0_1+0_3+0_5+0_7$
Implementation using 3:8 decodex
For active low outputs, modified expression are :-
$B_2=\overline{\overline{(0_4+0_5+0_6+0_7 )}}=\overline{ \overline{0_4.0_5.0_6 .0_7 }} \\[2ex] B_1=\overline{\overline{(0_3+0_4+0_6+0_7 )}}=\overline{ \overline{0_3.0_4.0_6 .0_7 }} \\[2ex] B_0=\overline{\overline{(0_1+0_3+0_5+0_7 )}}=\overline{ \overline{0_1.0_3.0_5 .0_7 }} $
