Sensors and signal conditioning

The challenge we take up in this fourth installment in a series of tutorials in instrumentation and measurement is to consider how to make a sensor work in a measurement system. Signal conditioning broadly includes the steps needed to make the sensor an active part of a measurement system by providing excitation, if required, and then performing the preliminary actions needed to obtain a signal that can be processed. What´s done to and with that signal is the subject of future parts of this tutorial series. Luckily, we don´t have to wait that long to get results, because the output of the signal conditioning stage can be used for something as simple as driving a display subsystem so that we see results. Signal conditioning is a critical step in a measurement system but so is each element as emphasized by the serial model we have been using so far to depict the basic elements of an instrument. However, it is important to keep in mind that many overall performance limits of a measurement are strongly influenced by what happens in the signal conditioning stage. For example, linearity, accuracy, noise rejection, and long-term drift behaviors will be strongly affected by decisions made here.