Multiplexer
1) Multiplexer
is a combinational circuit that select binary information from one of many inputs and direct it to single output.
2) The select of a particular input line
is controlled by a set of selection lines.
3) For example there are 2^ input lines
then there will be n selected lines.
4) For example if n=2 there will be 4
input lines and 2 selected lines.
5) The block diagram for 4x1 multiplexer is as
shown below.
6) The function table for 4x1
multiplexer is as shown below.
Explanation:
1) The 4to1 multiplexer consists of 4 input
lines they are I0,I1,I2 and I3.
2) There are 2 selection lines they are S1
and S0 select one input line from many input lines.
3) In this multiplexer circuit there are 4
AND gates and one OR gate. In this circuit only one AND gate will work at a
time.
4) For example let us consider the selection
input on 1,0 then the input line given to AND gate is I2.
5) The multiplexer is also known as data selector
because in multiplexer only one input lines and the output is generated through
the single output lines.
6) The diagram for quadruple
2 to 1 multiplexer is as shown below
Demultiplexer
1) Demultiplexer is a combinational circuit
that receives input information on a single line and transmits this information
on A one of 2n possible output line.
2) The selection of specific output line is
controlled by the bit values of n selection lines.
4) In this
diagram the input line is 6 and the selection lines are A and B and the output
lines are D0, D1, D2 and D3.
5) By using these selection lines we will
select a single output line.
6) The
circuit diagram for demultiplexer with decoder is as shown below.
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