Parity Generator and Checker
Parity Generator and Checker:
When the digital data is transmitted from one location to another. It is necessary to know at the receiving end whether the received data is free of error. A simple form of error detection is achieved by adding an extra bit to the transmitted word. This additional bit is known as the parity bit. It decides whether the data transmitted is error-free is not.
There are two types of parity bits, namely even parity and odd parity.
i. Even Parity: In an even parity system, the parity bit added to the word to be transmitted is chosen so that the number of 1’s in the modified word is even.
ii. Odd Parity: Odd parity means an n-bit input has an odd number of 1’s. The ASCII code for the decimal digit 9 (0111001) would require the addition of a 1 in the most significant place to give parity in the modified word.
A binary number may represent an instruction that tells the computer to add, subtract and so on. The binary number may also represent data to be processed like a number, letter, etc in a computer. In either case, an extra bit is added to the original binary number to produce a binary number with even or odd parity. Such an extra parity bit can be easily generated using an EX-NOR gate.