Introduction
Multiplexer and demultiplexer are used in pairs when they are used to transmit data over a single wire. All modern digital data communication is carried out by using a mux demux pair. This experiment demonstrates that theory. Data is transmitted from the mux and output is shown at the demux. The manual stimulus generator is used to switch channel and thus switch data on the demux ouput.
Components:
1. One CD4081 IC (AND Gate)
2. One CD4069 (NOT Gate)
3. One CD4071 (OR Gate)
4. Two Resistor 2.2KΩ, One 10KΩ Resistor
5. One tap switch
6. One LED (any color)
Steps:
1. Construct the circuit as shown in the schematic
2. Construct the manual stimulus generator using resistor and switch used/shown earlier, connect with Data_select input and Power ON
3. Push the tap switch and observe the outputs and its corresponding inputs and note them down
4. Release the tap switch and observe the outputs and its corresponding inputs and note them down
5. At the end of the experiment, compare the noted values with the truth table and the theory
Explanation:
This experiment shown how data is passed through a multiplexer and a demultiplexer. Both multiplexer and a demultiplexer is constructed and connected appropriately. Data is placed at the multiplexer input. The data then passes through the multiplexer and in to the demultiplexer output. If the circuit is constructed correctly, the data on the individual multiplexer input will match the data on the corresponding demultiplexer output. Both multiplexer and demultiplexer was explained earlier. This experiment demonstrates how both of these circuits are used in conjunction to each other.
From the schematice, note that two different wires travels from the mux to demux. Only one data carrier wire goes from the mux to demux. The other wire is the data selector. This experiment is demonstrating only a 2-bit data carrier. In case, of a 4-bit data carrier system, there will be 1 output, 4 data input channels and 2 data selection input (2 data selection as 22 = 4). The demux circuit will therefore have 1 data input and 2 data selection input. The number of data input channels on the mux does not matter, the demux will always require the 1 data output and all of the data selection inputs from the mux circuit. It should be noted that the data communication via a mux demux pair is unidirectional i.e. in one direction only.
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