Thursday, July 25, 2013

PPT On Binary Codes

Presentation On Binary Codes

Binary Codes Presentation Transcript:
1.Binary Codes

2.In the coding, when numbers, letters or words are represented by a specific group of symbols, it is said that the number, letter or word is being encoded.
The group of symbols is called as a code. The digital data is represented, stored and transmitted as group of binary bits. This group is also called as binary code. The binary code is represented by the number as well as alphanumeric letter.

Following is the list of advantages that binary code offers.
Binary codes are suitable for the computer applications.
Binary codes are suitable for the digital communications.
Binary codes make the analysis and designing of digital circuits if we use the binary codes.
Since only 0 & 1 are being used, implementation becomes easy.

4.Classification of binary codes
The codes are broadly categorized into following four categories.
Weighted Codes
Non-Weighted Codes
Binary Coded Decimal Code
Alphanumeric Codes
Error Detecting Codes
Error Correcting Codes

5.Weighted Codes
Weighted binary codes are those binary codes which obey the positional weight principle. Each position of the number represents a specific weight. Several systems of the codes are used to express the decimal digits 0 through 9. In these codes each decimal digit is represented by a group of four bits.

6.Weighted Codes

7.Non-Weighted Codes
In this type of binary codes, the positional weights are not assigned. The examples of non-weighted codes are Excess-3 code and Gray code.
EXCESS-3 CODE
The Excess-3 code is also called as XS-3 code. It is non-weighted code used to express decimal numbers. The Excess-3 code words are derived from the 8421 BCD code words adding (0011)2 or (3)10 to each code word in 8421. The excess-3 codes are obtained as follows

8.GRAY CODE
It is the non-weighted code and it is not arithmetic codes. That means there are no specific weights assigned to the bit position. It has a very special feature that has only one bit will change, each time the decimal number is incremented as shown in fig. As only one bit changes at a time, the gray code is called as a unit distance code. The gray code is a cyclic code. Gray code cannot be used for arithmetic operation.

9.APPLICATION OF GRAY CODE
Gray code is popularly used in the shaft position encoders.
A shaft position encoder produces a code word which represents the angular position of the shaft.

10.Binary Coded Decimal (BCD) code
In this code each decimal digit is represented by a 4-bit binary number. BCD is a way to express each of the decimal digits with a binary code. In the BCD, with four bits we can represent sixteen numbers (0000 to 1111). But in BCD code only first ten of these are used (0000 to 1001). The remaining six code combinations i.e. 1010 to 1111 are invalid in BCD.