A demultiplexer, often abbreviated as "demux," is a digital circuit component that takes a single input signal and directs it to one of several output lines based on the control signals provided. It performs the reverse function of a multiplexer, which combines multiple input signals into a single output line.
In simpler terms, a demultiplexer acts like a distribution system for digital data. It takes a single data input and selects which output line to send the data to, based on the binary values of its control inputs. The control inputs determine which output line is activated, allowing the input data to be "demultiplexed" to the desired output line.
A demultiplexer is typically represented by the following symbol:
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-| DEMUX |-
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The basic operation of a demultiplexer can be understood with a simple example. Let's consider a 1-to-4 demultiplexer, which means it has one data input, two control inputs (to select one of four output lines), and four output lines. The control inputs determine which output line receives the input data.
Here's how it works:
The demultiplexer takes in a single data input.
The control inputs specify which output line should be activated.
The input data is then directed to the selected output line, and the other output lines remain inactive.
In digital circuits, demultiplexers have various applications. One common use is in memory systems, such as dynamic random-access memory (DRAM), where a single address line is "demultiplexed" into multiple row and column addresses to access specific memory cells. Demultiplexers are also used in data routing, signal distribution, and in scenarios where a single data source needs to be distributed to multiple destinations based on control signals.
To summarize, a demultiplexer is a digital circuit component that takes a single input and routes it to one of several output lines based on control inputs. It is a fundamental building block in digital design and finds applications in various scenarios where data needs to be distributed selectively.