Multiplexer and Demultiplexer PDF

What Are Multiplexers? A multiplexer is a combinational circuit that has many data inputs and a single output, depending on control or select inputs. For N input lines, log2(N) selection lines are required, or equivalently, for 2n input lines, n selection lines are needed. Multiplexers are also kno...

What Are Multiplexers? A multiplexer is a combinational circuit that has many data inputs and a single output, depending on control or select inputs. For N input lines, log2(N) selection lines are required, or equivalently, for 2n input lines, n selection lines are needed. Multiplexers are also known as “N-to-1 selectors,” parallel- to-serial converters, many-to-one circuits, and universal logic circuits. They are mainly used to increase the amount of data that can be sent over a network within a certain amount of time and bandwidth. Multiplexer can act as universal combinational circuit. All the standard logic gates can be implemented with multiplexers. 4×1 Multiplexer The 4×1 Multiplexer which is also known as the 4-to-1 multiplexer. It is a multiplexer that has 4 inputs and a single output. The Output is selected as one of the 4 inputs which is based on the selection inputs. The number of the Selection lines will depend on the number of the input which is determined by the equation log2n, In 4×1 Mux the selection lines can be determined as log4=2 ,so two selections are needed. Block Diagram of 4×1 Multiplexer In the Given Block Diagram I0, I1, I2, and I3 are the 4 inputs and Y is the Single output which is based on Select lines S0 and S1. The output of the multiplexer is determined by the binary value of the selection lines When S1S0=00, the input I0 is selected. When S1S0=01, the input I1 is selected. When S1S0=10, the input I2 is selected. When S1S0=11, the input I3 is selected. Truth Table of 4×1 Multiplexer Given Below is the Truth Table of 4×1 Multiplexer Circuit Diagram of 4×1 Multiplexers Using truth table the circuit diagram can be given as: What is Demultiplexer (DEMUX)? The DEMUX is a digital information processor. It takes input from one source and also converts the data to transmit towards various sources. The demultiplexer has one data input line. The demultiplexer has several control lines (also known as select lines). These lines determine to which output the input data should be sent. The number of control lines determines the number of output lines. General Block Diagram Of A DEMUX Here is the basic block diagram of a DEMUX as mentioned below. Truth Table Of A 1X4 DEMUX A 1x4 DEMUX has only one input which is denoted as I. There are two selection lines i.e. S1 and S0. At last, the DEMUX has output lines including Y3, Y2, Y1 &Y0. Here is the 1x4 DEMUX with diagram as mentioned below. Now let us discuss the truth table of the 1x4 DEMUX as mentioned below. Selection Inputs Outputs S1 S0 Y3 Y2 Y1 Y0 0 0 0 0 0 I 0 1 0 0 I 0 1 0 0 I 0 0 1 1 I 0 0 0 Advantages and Disadvantages of the DEMUX Now, we are going to discuss the advantages and disadvantages of the DEMUX as mentioned below. Advantages of the DEMUX The DEMUX increases the efficiency of the particular communication system as it takes data from a specific input source and distributes it to different sources. The DEMUX helps to separate the different signals from the mixed data sources. Then it distributes these data to different sources. DEMUX can decode the signal outputs of the multiplexer, as the system works in a reverse way of the MUX. Disadvantages of the DEMUX The DEMUX may cause a wastage of bandwidth as it distributes the refined data in different channels. These channels can overlap with each other which leads to the loss of signal. The DEMUX may cause problems in the synchronization of signals. The data channels can overlap with each other which leads to the delay in the whole process. Applications of DEMUX DEMUXs are majorly used to design the ALU circuits and parallel data segments. The DEMUXs convert the output of the MUX into the actual input. On the receiver end, the DEMUX can be used to verify the original form of the data to carry out the entire communication process. DEMUX helps to save the output. The output generally saved to the ALU. The output will be saved in the registers and the various storage units of the system.  Each DEMUX has a connection with multiple registers which helps to store the processed data into it. The counterpart of the DEMUX regulates the data signal at the output stage of the DEMUX operation. These data can be retrieved later to read out parallelly. In the audio or video system, the DEMUX distributes them in different channels. In broadcasting, the DEMUX separates the composite signal into an individual one. Difference Between of Multiplexer and Demultiplexer Multiplexer Demultiplexer Multiplexer processes the Demultiplexer receives digital digital information from various information from a single source and sources into a single source. converts it into several sources It is known as Data Selector It is known as Data Distributor Multiplexer is a digital switch Demultiplexer is a digital circuit It follows combinational logic It also follows combinational logic type type It has 2n input data lines It has single input line It has a single output data line It has 2n output data lines It works on many to one It works on one to many operational operational principle principle  Multiplexer Demultiplexer In time division Multiplexing, In time division Multiplexing, multiplexer is used at the demultiplexer is used at the receiver end transmitter end