1. EKT 124
MUX AND DEMUX

2. Multiplexer (MUX) – Data Selector
A multiplexers (MUX) is a device that allows digital information from several sources to be routed onto a single line for transmission over that line to a common destination.
The basic multiplexers has several data input lines and a single output line. It also has data- select inputs, which permit digital data on any one of the inputs to be switched to the output line

3. Functional Diagram of a MUX

4. Functional Diagram of a MUX
A multiplexer has
N control inputs
2N data inputs
1 output (Z)
A multiplexer routes (or connects) the selected data input to the output.
The value of the control inputs determines the data input that is selected. N 2N

5. MUX – Function Table and Boolean Expression
MSB
LSB A B Z I0 1 I1 I2 I3
Z = A′.B'.I0 + A'.B.I1 + A.B'.I2 + A.B.I3

6. MUX – Function Table and Boolean Expression
MSB
LSB A B C Z I0 1 I1 I2 I3 I4 I5 I6 I7
Z = A′.B'.C'.I0 + A'.B'.C.I1 + A'.B.C'.I2 + A'.B.C.I3 +
A.B'.C'.I4 + A.B'.C.I5 + A'.B.C'.I6 + A.B.C.I7

7. MUX – Output Waveforms in relation with the Data-Input and Data-Select waveforms
The binary state of the data-select inputs during each interval determines which data input is selected.
Here the data-select inputs go through a repetitive binary sequence 00,01,10,11,00 and so on.

8. Designing logic circuit using MUX

9. Designing logic circuit using MUX

10. Cascading MUX Using three 2-1 MUX to make one 4-1 MUX S1 S0 F I0 1 I1I0 1 I1 I2 I3

11. Cascading MUX Example: Construct an 8-to-1 multiplexer using
2-to-1 multiplexers. F
2-1
MUX
S E
S2 E I0 I1 I2 I3 I4 I5 I6 I7 S2 S1 S0 F I0 1 I1 I2 I3 I4 I5 I6 I7

12. Demultiplexer : DEMUX It reverses the multiplexing function.
It takes data from one line and distributes them to a given number of output lines. It is also known as a data distributor.
A demultiplexer takes a single input and distributes it over several outputs.
Compares to MUX : A multiplexer takes several inputs and transmits one of them to the output.

13. DEMUX : Functional Diagram
A demultiplexer switches (or routes) data from one input to 2N outputs, where N is the number of select inputs.

14. DEMUX : Output Waveforms

15. DEMUX I W X Y Z A B W = A'.B'.I X = A.B'.I Y = A'.B.I Z = A.B.I In
Out0 In S1 S0 I W X Y Z A B
Out1
Out2
Out3
W = A'.B'.I
X = A.B'.I
Y = A'.B.I
Z = A.B.I A B W X Y Z I 1

16. Thank You