In: Electrical Engineering
gray code to excess 3 code converter circuit and its logic diagram and ic based diagram
To convert gray code to Excess 3 code , we will first convert it to BCD and then convert it it excess 3 codes.
Lets say we have gray code with bits G1,G2,G3 and G4 ( G4 is LSB).
The equivalent binary would be A,B,C, D (D is LSB) and the equivalent excess 3 would be w,x,y,z (z is LSB).
We will need a 4 bit truth table to represent as there are 10 different BCD combinations possible.
We will use the following truth table to create the karnaugh maps for the conversion.
Decimal Value | G1 | G2 | G3 | G4 | A | B | C | D | w | x | y | z |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 |
2 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 |
3 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 0 |
4 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 |
5 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 0 | 0 |
6 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 |
7 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 0 |
8 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 1 |
9 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 0 |
10 | 1 | 1 | 1 | 1 | X | X | X | X | X | X | X | X |
11 | 1 | 1 | 1 | 0 | X | X | X | X | X | X | X | X |
12 | 1 | 0 | 1 | 0 | X | X | X | X | X | X | X | X |
13 | 1 | 0 | 1 | 1 | X | X | X | X | X | X | X | X |
14 | 1 | 0 | 0 | 1 | X | X | X | X | X | X | X | X |
15 | 1 | 0 | 0 | 0 | X | X | X | X | X | X | X | X |
Solving the Karnaugh Map -
The karnaugh Map for Gray Code to BCD Conversion is:
The karnaugh Map for BCD to Excess-3 code Conversion is:
Using the above Simplified Expressions, we can convert gray code to equivalent excess 3 code.
The simplified IC diagram representation is shown below: