Java Tutorials and Projects: BINARY CODES

There are four types of binary codes. They are:

a. BCD code

b. Excess-3 code

c. Gray code

d. Parity bit.

=>BCD Code

1. Here BCD means “Binary Coded Decimal”.

2. In BCD code we have to write the binary form for each and every digit in the given number.

3. For example:- Given number is 125.

4. To write the binary code for 125 we have to write the binary form for each digit in 125 as shown below.

Solution:

1 2 5

0001 0010 0101

If we write 125 in binary form we get : 1111101.

NOTE:-

From the above example there are 12 bits in BCD form whereas there are 7 bits in binary form.
Therefore, the BCD code consists of more number of bits than binary code.
Therefore, the BCD code is less efficient than the binary number system.
The BCD code is also known as 8 – 4 – 2 – 1.
8-4-2-1 can be represented as shown in the following table.

=>Excess-3 Code

1. In excess-3 code we have to add 3 to every binary number.

2. The excess-3 code for decimal numbers is as shown in the following table

=>GRAY CODE

1. In gray code the successive code or the consecutive binary code will differ in one bit only.

2. The gray code for decimal numbers is as shown in the following table

=>PARITY BIT

1. By using parity bit we can check whether the given number is received correctly or not.

2. The parity bits are of two types .They are:-

a. Even parity

b. Odd parity.

3. When we give the even parity along with input message then if the number of one’s present are even then it is known as even parity.

4. When we give the input message along with odd parity and if the number of one’s are odd then it is known as odd parity.

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