Solution:

• The encoding function is performed by a logic circuit called an encoder. The encoder converts information, such as a decimal number or an alphabetic character, into some coded form.

• For example, one certain type of encoder converts each of the decimal digits, 0 through 9, to a binary code.

• A HIGH level on the input corresponding to a specific decimal digit produces logic levels that represent the proper binary code on the output lines.

• Figure is a simple illustration of an encoder used to convert (encode) a calculator keystroke into a binary code that can be processed by the calculator circuits.

The Decoding Function:

• The decoding function is performed by a logic circuit called a decoder. The decoder converts coded information, such as a binary number, into a noncoded form, such as a decimal form.

• For example, one particular type of decoder converts a 4-bit binary code into the appropriate decimal digit.

• Figure is a simple illustration of one type of decoder that is used to activate a 7-segment display.

• Each of the seven segments of the display is connected to an output line from the decoder.

• When a particular binary code appears on the decoder inputs, the appropriate output lines are activated and light the proper segments to display the decimal digit corresponding to the binary code.