A multiplexer is a device that allows you to select between multiple analog or digital input signals and transfer them to a single line output. This system is called data selector. Digital multiplexers can also be used to implement Boolean logic with many variables. Analog selectors allow several signals to share one device or resource, for example, single sensor, analog-to-digital system, instead of having one device for each line of the input signal.
An electronic multiplexer can be considered as a switch with multiple inputs and one output. The character count in the wiring diagram is an isosceles trapezoid with the long side parallel input contains contacts and a short parallel side containing the output from the system. Control line connected the supply line is taken, usually from the side, with the slope of the sides of a trapezoid. Given digital control of the multiplexer, as a rule, they have 2n inputs, where n is a natural number: 2, 3, 4, 5 etc. The multiplexers can be controlled in parallel using the n-bit interface, or sequentially, for example using SPI interface or I2C interface.
When designing an analog multiplexer is a special type of analogue switch that connects one signal selected from several inputs to one output. This element is characterized, in addition to the number of input channels and type of management interface, as well as a number of other important electrical parameters that need to pay attention when choosing the right item. The two most important characteristics of this system are the frequency response and maximum signal amplitude. The number suggests that the highest frequency signal that can be transmitted through the system. Similarly, the amplitude of the signal indicates the maximum voltage of the signal that are not przesteruje input multiplexer.
In digital systems the selector switch digital signals. In this case, as the signals remote access and control signals to digital. Systems of this type have, as a rule, 2, 4, 8 or 16 inputs, but there are also digital multiplexers on an even larger number of control inputs. Already having 16 inputs selector requires at least 4 control lines. In the case of parallel interface system with a large number of inputs are often equipped with serial interfaces for management, which reduces the number of necessary control pins. Digital multiplexers are mainly used to increase the amount of data that can be transmitted through the network at a certain time and bandwidth.