Parity Generator
A parity generator is a combinational circuit that accepts n-1 bits of data and generates additional bits. The additional bit of data is known as the parity bit.
There are two kinds of parity generators: Even parity generators and Odd parity generators.
Even Parity Generator
To understand even parity generator, let us take an example:
Let us assume a 3-bit message that needs to be transmitted using an even parity bit.
The truth table will be as follows:
| 3-bit message | Even parity generator | ||
| A | B | C | Y |
| 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 1 |
| 0 | 1 | 0 | 1 |
| 0 | 1 | 1 | 0 |
| 1 | 0 | 0 | 1 |
| 1 | 0 | 1 | 0 |
| 1 | 1 | 0 | 0 |
| 1 | 1 | 1 | 1 |
The logical expression will be:
Odd Parity Generator
The truth table for an odd parity generator will be as follows:
| 3-bit message | Odd parity generator | ||
| A | B | C | Y |
| 0 | 0 | 0 | 1 |
| 0 | 0 | 1 | 0 |
| 0 | 1 | 0 | 0 |
| 0 | 1 | 1 | 1 |
| 1 | 0 | 0 | 0 |
| 1 | 0 | 1 | 1 |
| 1 | 1 | 0 | 1 |
| 1 | 1 | 1 | 0 |
Logical expression:
P = A ⊕ (B ⊕ C)
Reference