A multiplexer, often abbreviated as MUX, is a fundamental digital electronic device that is used to select one out of multiple input data lines and route it to a single output line. It's commonly used in digital systems for data selection, signal routing, and switching purposes. The operation of a multiplexer is based on controlling the selection of input data lines using control signals.
A typical multiplexer has two main components:
Data Inputs: These are the various input lines where different data sources are connected. A multiplexer can have 2^n data inputs, where "n" is the number of select lines or control lines. So, if you have 2 select lines, you can have 2^2 = 4 data inputs, and if you have 3 select lines, you can have 2^3 = 8 data inputs, and so on.
Select Lines (Control Lines): These lines determine which input data line is selected to be routed to the output. The number of select lines depends on the number of data inputs. As mentioned earlier, the formula is 2^n, where "n" is the number of select lines. The select lines determine the binary code that specifies which input is being selected. For example, if you have 2 select lines, you can represent 4 possible combinations (00, 01, 10, 11), and each combination corresponds to a different input being selected.
Here's a step-by-step explanation of how a multiplexer works:
Control Input: The control inputs (select lines) are set to a binary code that corresponds to the input line you want to select. For example, if you have 2 select lines and want to select the second input, you would set the select lines to "01".
Selection Logic: Inside the multiplexer, there is selection logic that interprets the binary code from the control inputs. This logic activates the appropriate data input line based on the control input.
Data Routing: The data from the selected input line is routed to the output of the multiplexer. This means that the data present on the selected input line is transferred to the output line.
Output: The selected data is available on the output of the multiplexer. The output is essentially the same as the selected input line.
In summary, a multiplexer enables the selection of one out of several input data lines to be passed through to the output based on the configuration of the select lines. This is particularly useful in scenarios where you want to switch between different data sources efficiently, such as in data routing, signal processing, memory addressing, and more.