1×2 Demultiplexer Truth Table
The table below illustrates the routing relationship between Data Input (D), Select Line (S), and the two Output lines (Y0, Y1). The row matching the current simulator state is automatically highlighted.
| Input (D) | Select (S) | Output Y0 (D · S̅) | Output Y1 (D · S) | Selected Channel | Status |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | Y0 | |
| 1 | 0 | 1 | 0 | Y0 | |
| 0 | 1 | 0 | 0 | Y1 | |
| 1 | 1 | 0 | 1 | Y1 |
What is a Demultiplexer?
A Demultiplexer (DEMUX) is a combinational logic circuit that accepts a single data input line and distributes it to one of multiple output lines based on the binary state of control or select inputs.
Why is it called a Data Distributor?
A demultiplexer acts as a digital rotary switch. Just like an electrical switch directs incoming current to one of several branches, a DEMUX routes a single data stream (Input D) to a specific destination output line (Y0 or Y1). Hence, it is commonly called a Data Distributor.
Detailed Signal Descriptions
- Data Input (D): The single binary signal (0 or 1) that is to be transmitted to the selected output line.
- Select Line (S): The control line that determines which output receives the data input. With 1 select line, 21 = 2 outputs can be addressed.
- Outputs (Y0, Y1): The destination lines. When S = 0, output Y0 receives D. When S = 1, output Y1 receives D. The unselected output is held forced at 0.
Multiplexer (MUX) vs Demultiplexer (DEMUX)
Multiplexers and Demultiplexers perform inverse operations in digital communication and logic networks.
MULTIPLEXER (MUX)
Function: Data Selector
Takes Many Inputs and selects One Output.
Output: Y
Operation: Y = I0·S̅ + I1·S
DEMULTIPLEXER (DEMUX)
Function: Data Distributor
Takes One Input and routes to Many Outputs.
Outputs: Y0, Y1, ... Yn
Operation: Y0 = D·S̅ , Y1 = D·S
In telecommunications, a MUX combines multiple data signals into a single transmission line, while a DEMUX at the receiving end separates the single transmission back into individual signal channels.
Boolean Logic Equations
The logic expressions for the two outputs of a 1×2 Demultiplexer are derived directly from the AND combination of the Data Input (D) and the inverted/non-inverted Select Line (S):
Live Evaluated Output Equations:
Industrial & Digital System Applications
- Data Distribution: Routing central processor data to multiple peripheral devices (e.g. Memory banks, Displays, Printers).
- Signal Routing: Directing analog or digital audio/video channels in broadcast switching equipment.
- Communication Systems: Demultiplexing Time-Division Multiplexed (TDM) incoming signals back into individual user channels.
- Digital Switching: Implementing decoder circuits and address decoding in microprocessor memory units.
- Serial-to-Parallel Converters: Converting serial incoming bitstreams into multi-bit parallel outputs when paired with a clock/counter.
- Control Systems & Data Acquisition: Distributing sensor trigger pulses and control signals to specific actuators.
Interactive Application Demo: Dual-Channel Audio Router
Toggle inputs D and S to see how a 1×2 Demultiplexer routes an incoming audio signal stream to Speaker Channel A (Y0) or Speaker Channel B (Y1).