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Experiment: 4 Date: August 14, 2012

Aim: To design and verify the circuit of 16X1 Multiplexer using 4X1 Multiplexer in Structural

modelling.

Theory:

A Multiplexer (or MUX) is a device (combinational logic circuit) that selects one of several analog or

digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n

select lines, which are used to select which input line to send to the output. Multiplexers are mainly

used to increase the amount of data that can be sent over the network within a certain amount of

time and bandwidth. A multiplexer is also called a data selector. They are used in CCTV, and almost

every business that has CCTV fitted, will own one of these.

An electronic multiplexer makes it possible for several signals to share one device or resource, for

example one A/D converter or one communication line, instead of having one device per input

signal.

An electronic multiplexer can be considered as a multiple-input, single-output switch, and a

demultiplexer as a single-input, multiple-output switch. The schematic symbol for a multiplexer is an

isosceles trapezoid with the longer parallel side containing the input pins and the short parallel side

containing the output pin.

The truth table of the Multiplexer is shown below.

Enable S1 S2 Out

1 X X 0

0 0 0 In1

0 0 1 In2

0 1 0 In3

0 1 1 In4

Expt. 4: 16X1 MUX using 4X1 MUX

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VHDL Code:

4X1 MUX:

Expt. 4: 16X1 MUX using 4X1 MUX

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16X1 MUX:

Expt. 4: 16X1 MUX using 4X1 MUX

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RTL Schematics:

Expt. 4: 16X1 MUX using 4X1 MUX

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Expt. 4: 16X1 MUX using 4X1 MUX

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Output Waveforms: