Difference Between Multiplexer And Demultiplexer (With Examples)

What Is A Multiplexer (MUX)?

A multiplexer also referred to as a data selector, is a device that selects between several analog or digital input signals and forwards the selected input to a single output line. In other words, it is a combination logic circuit designed to switch one of several input lines through to a single common output line by the application of a control signal.

A multiplexer makes it possible for several input signals to share one device or resource, for example, one analog-to-digital converter or one communication transmission medium, instead of having one device per input signal. A multiplexer is often used with a complementary de-multiplexer on the receiving end.

Generally, the selection of each input line in a multiplexer is controlled by an additional set of inputs referred to as control lines and according to the binary condition of these control inputs, either “high” or “low” the appropriate data input is connected directly to the output. Normally, a multiplexer has an even number of 2ⁿ data input lines and a number of “control” inputs that correspond with the number of data inputs.

It is important to note that multiplexers are quite different in operation to Encoders. Encoders are able to switch an n-bit input pattern to multiple output lines that represent the binary coded output equivalent of the active input.

Multiplexers can either be digital circuits made from high speed logic gates used to switch digital or binary data or they can be analogue types using transistors, MOSFET’s or relays to switch one of the voltage or current inputs through to a single output.

Types of Multiplexers

There are mainly two types of multiplexers, namely analog and digital. They are further divided into:

• Frequency Division Multiplexing  (FDM)
• Wavelength Division Multiplexing (WDM)
• Time Division Multiplexing (TDM)

Facts About Multiplexer

• A multiplexer is a combinational circuit that provides single output but accepts multiple data inputs.
• It has multiple inputs and one output.
• It includes data selectors.
• Parallel to serial conversion.
• It works on many-to-one operation principle.
• Additional gates are not required when designing multiplexers.
• In time division multiplexing, multiplexer is used at the transmitter end.
• Multiplexer with the help of control signals selects the particular input that has to be transmitted at the output.
• MUX system increases the efficiency of the communication system by allowing the transmission data, such as audio and video transmission.
• Examples of multiplexer include: 8 input 1 output, 16 input 1 output, 32 input 1 output.

Also Read: Difference Between Combinational And Sequential Logic Circuit

What Is A Demultiplexer (DEMUX)?

The Demultiplexer  is a combination logic circuit designed to switch one common input line to one of several separate output line. It is an exact opposite of a Multiplexer. The demultiplexer takes one single input data line and then switch it to any one of a number of individual output lines one at a time.

Demultiplexers are also referred to as data distributors, since they transmit the same which is received at the input to different destinations.  The output lines of demultiplexer are ‘n’ in number, select line number is ‘m’ and n=2^m. The control signal or select input code decides the output line which the input has to be transmitted.

Demultiplexers are used in several fields where there is a necessity of connecting single source to several destinations. These applications of a demultiplexer include:

• They are used in clock data recovery solutions
• Arithmetic and Logic Unit
• They are used in communication system for transmission of data
• ATM packets broadcasting
• Used in wavelength routers.

Types of Demultiplexers

• 1:2 Demultiplexer
• 1:4 Demultiplexer
• 1:8 Demultiplexer
• 1:16 Demultiplexer

Facts About Demultiplexer

• A demultiplexer is a combination circuit that takes single input but that input can be directed through multiple outputs.
• It has one input and multiple outputs.
• It includes data distributors.
• Serial to parallel connection.
• It works on one-to-many operational principle.
• Additional gates are included when designing de-multiplexer.
• In time division multiplexing, demultiplexer is used at the receiver end.
• Demultiplexer utilizes the control signal and allows us to have multiple outputs.
• DEMUX receive the output signals from the multiplexer and convert them back to the original form at the receiver end.
• Examples of demultiplexer include:  1 input 8 output, 1 input 16 output, 1 input 32 output.

Also Read: Difference Between Encoder And Decoder

Difference Between Multiplexer And Demultiplexer In Tabular Form

Also Read: Difference Between Mealy And Moore Machine