RFConcentrator vs. Multiplexer: Key Differences Explained
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This article clarifies the difference between a concentrator and a multiplexer, two common devices used in communication systems.
What is a Multiplexer?
A multiplexer (MUX) is a digital circuit that selects one of several input signals and forwards it to a single output line. The selection is determined by a set of selection lines.
Image alt: Multiplexer
Think of it like a train switchyard. Multiple tracks (input lines) converge into one, and the switch (selection lines) determines which track’s train (data) continues onto the main line (output line).
For example, a 4X1 MUX, as the name suggests, has four input lines and one output line. The following table illustrates how the selection lines (s1, s0) control which input is routed to the output:
| Selection line (s1, s0) | Output line |
|---|---|
| 00 | I0 |
| 01 | I1 |
| 10 | I2 |
| 11 | I3 |
What is a Concentrator?
A concentrator is primarily used in circuit-switched systems, especially within the access network. Its main function is to concentrate traffic from multiple low-capacity channels onto a smaller number of higher-capacity channels.
Image alt: Concentrator
Imagine several smaller roads merging into a single, wider highway. The concentrator performs a similar function for data traffic. ‘n’ number of channels are concentrated onto ‘m’ number of channels, where m < n.
The outgoing link’s capacity (m) must be carefully chosen to keep the call blocking probability low, ensuring the Quality of Service (QoS) requirements are met. It’s also a device that acts as an efficient forwarder of data transmission signals.
Example: A remote access Hub is a type of concentrator. Cisco’s VPN 3000 series is another example of a concentrator.
Key Differences Summarized
In essence:
- Multiplexer: Selects one of several inputs and directs it to a single output. It’s a selection process.
- Concentrator: Combines traffic from multiple channels into a smaller number of channels. It’s a concentration process, aiming for efficient bandwidth utilization. Concentrators are generally employed in circuit switched systems.
