A multiplexer, often abbreviated as MUX, is a digital electronic device that allows you to select one of many input data sources and route it to a single output. It's commonly used in various applications where data needs to be selected from multiple sources and sent to a single destination. The operation of a multiplexer is quite straightforward, and it plays a crucial role in digital circuits, communication systems, and computer architectures.
A multiplexer has two main types of inputs: data inputs (often denoted as D0, D1, D2, etc.) and control inputs (often denoted as S0, S1, S2, etc.). The control inputs determine which data input gets propagated to the output. The number of control inputs corresponds to the number of data inputs available for selection. The relationship between the number of data inputs and control inputs can be expressed as:
Number of data inputs = 2^n, where n is the number of control inputs.
Here's a simple explanation of how a multiplexer operates:
Data Inputs (D0, D1, D2, ...): These are the different sources of data that you want to choose from. Each data input could represent a binary digit (0 or 1) or a more complex signal.
Control Inputs (S0, S1, S2, ...): These inputs determine which data input is selected. The number of control inputs is determined by the number of data inputs. For example, if you have 4 data inputs (D0 to D3), you will need 2 control inputs (S0 and S1) to select one of the 4 data inputs.
Output (Y): This is the single output line where the selected data input is sent.
The operation can be summarized as follows:
The control inputs are set to a binary value that corresponds to the desired data input to be selected. For example, if you have 4 data inputs (D0 to D3), the control inputs (S0 and S1) can be set to binary values 00, 01, 10, or 11 to select D0, D1, D2, or D3, respectively.
The selected data input is then routed to the output line. This means that the value present at the selected data input is transferred to the output.
The other data inputs that were not selected do not affect the output and are effectively disconnected from it.
In essence, a multiplexer acts like a switch that can be controlled using its control inputs to connect one of several data inputs to its output. This is particularly useful in scenarios where you want to transmit data from multiple sources to a single receiver or processor, and you need a way to select which source's data to process or transmit.