Multiplexing

Multiplexing is a technique that allows the simultaneous transmission of multiple signals or streams of data over a single communication channel or medium. It achieves this by dividing the channel's resources, such as bandwidth or time, amongst the different signals. This division can occur through various methods, including time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), and wavelength division multiplexing (WDM). The receiving end then demultiplexes the combined signal to separate the original individual signals. The aim of multiplexing is to improve efficiency and reduce infrastructure costs.

Multiplexing meaning with examples

• In the early days of television broadcasting, multiplexing was used to send the video and audio signals over a single radio frequency. This allowed for efficient use of the available spectrum. Furthermore, modern digital television relies heavily on multiplexing to deliver multiple channels of content, including standard-definition and high-definition programming, over a single broadcast signal, enabling a wider range of programming options for viewers and optimising the use of broadcast bandwidth.
• A common example of multiplexing is found in telecommunications. A telephone company uses multiplexing to combine multiple voice calls onto a single high-capacity trunk line. This efficient use of the physical infrastructure reduces the cost and complexity of establishing and maintaining a vast network. Modern fiber optic networks use wavelength division multiplexing, where data is transmitted on multiple light wavelengths.
• In computer networking, multiplexing allows several devices to share a single network connection. For instance, home routers use multiplexing to allow multiple computers, smartphones, and other devices to simultaneously access the internet via a single broadband connection. This is typically accomplished via time-division or statistical multiplexing. It prevents resource bottlenecks and ensures smooth data transfer.
• Radio broadcasting uses multiplexing to add supplementary information to audio signals, like FM radio sending audio with RDS. In other fields, data acquisition systems often utilize multiplexing to collect sensor data from multiple sources over a single cable. The data stream is later demultiplexed and used for monitoring, control and analysis. These ensure effective utilization of resources and bandwidth.