Multiplexer Basics
Multiplexer or Mux is a logic device that can be used to transmit digital signals from multiple sources via a single wire. A mux allows data communication through a very few number of wires that can reduce the cost of implementing the system. A Mux consists of individual inputs pins for multiple different sources and one or more pins for selecting the active transmitting source. It should be noted that only one source is connected to the mux output at a time. To ensure all sources have a chance to connect to the output, the multiplexer uses a method known as “ Time Sharing ”. The time sharing method is used extensively in telecommunication industry. All types of wired and wireless communication system like Cell phone and internet uses time sharing. In fact the internet/WiFi routers we use at home are a very advanced multiplexer.
A multiplexer always sits on the transmission side. The sources are often called channel. A mux uses multiple user defined selection logic signals to select the sources connected to the output. However, the receiving end will have no idea about which channel is being currently transmitted. Therefore, to ensure the receiver knows which channel is active, the selection logic is also transmitted with the mux output. The receiver combines the selection logic and the output to figure out the correct output channel.
The multiplexer is described in more details in the Experiment-9. In the experiment, we explore the mux circuit and its working theory in real life.
