Decoder
Decoder is the combinational circuit that change the binary information into 2N output lines
The binary information is passed in the form of N input lines. The output lines define the 2N-bit code for the binary information.
In simple words, the Decoder performs the reverse operation of the Encoder. At a time, only one input line is activated for simplicity. The produced 2N-bit output code is equivalent to the binary information.
Block Diagram of Decoder
There are various types of decoders which are as follows:
- 2 * 4 line decoder
- 3 * 8 line decoder
- 4 * 16 line Decoder
3 * 8 line Decoder
The 3 to 8 line decoder is also known as Binary to Octal Decoder. In a 3 to 8 line decoder, there is a total of eight outputs and three inputs.
The block diagram and the truth table of the 3 to 8 line encoder are given below.
Truth Table of 3*8 Decoder
The truth table for the 3* 8 Decoder is as given below:
Boolean Expressions
The boolean expressions of the output terms is as follows:
Y0=A0‘.A1‘.A2‘
Y1=A0.A1‘.A2‘
Y2=A0‘.A1.A2‘
Y3=A0.A1.A2‘
Y4=A0‘.A1‘.A2
Y5=A0.A1‘.A2
Y6=A0‘.A1.A2
Y7=A0.A1.A2
Circuit Diagram
Circuit Diagram of the above expressions is given below:
