Codes and Code Converters

Codes and code converters

Coding is the process of translating the input information which can be understandable by the machine or a particular device. Coding can be used for security purpose to protect the information from steeling or interrupting. Actually this is not the latest trend, in previous days also the king of the kingdom used to send the information to other kingdom which some code words.

The code converters are used to convert the information in to the code which we want. These are basically encoders and decoders which converts the data in to an encoded form. The below explains some digital codes used in digital electronics.

 

 ASCII: 

ASCII (American Standard for information exchange): It is a character encoding scheme for computer to represent the English alphabet and to communicate with the devices which uses text as controlling commands. ACSII code was developed a long ago to represent the English letters with the numbers which are understandable by digital equipment. If anyone ask to write a letter in ACSII format means writing only alphabets without formatting. Writing a letter in notepad is one of the examples for ASCII format. We cannot do any formatting in notepad like BOLD, TAB etc.

      

Excess-3 code:

It is also known as self complementary code as the complement of any number (0-9) will be available within these 10 numbers. As the name implies it is excess of 3 for the regular BCD code i.e. if u add 3(0011) to the BCD Addition u can get Excess-3 code.

Grey code

It is also called as unit distance code and reflective code word. It is not arithmetic code that there are no specific weights assigned to each bit positions.

1)      The successive code wards differ only one bit this nature of the code is called unit distance code

The above table shows the Decimal, BCD and Grey code, the last column shows grey code of Decimal 1, 2, 3 & 4. The grey code for 1 & 2 differs only one bit same for 2&3 etc. that’s y this code is called unit distance code as the distance between the successive codes Is one bit.

Switching activity is reduced because of one digit change in consequence numbers, hence low power consumption and fast response.

1)      It is also called as reflective code as the code of n bits are again reflected from n bit code. In the below table u can find 2 bit code which shows the reflective nature of 0 is 2 and 1 is 3. Same is applicable for 3 bit code.

 

The above table shows the Decimal, BCD and Grey code, the last column shows grey code of Decimal 1, 2, 3 & 4. The grey code for 1 & 2 differs only one bit same for 2&3 etc. that’s y this code is called unit distance code as the distance between the successive codes Is one bit.

Switching activity is reduced because of one digit change in consequence numbers, hence low power consumption and fast response.

1)      It is also called as reflective code as the code of n bits are again reflected from n bit code. In the below table u can find 2 bit code which shows the reflective nature of 0 is 2 and 1 is 3. Same is applicable for 3 bit code.

Applications:

1)      Counter Successive approximation ADC

 

2)

 

Code Converters:

1)      BCD to Grey Code

 BCD to Grey COde converter usig EXOR gate

Recent Posts