What Is Noise On A Signal?
Noise is the unwanted part of a signal. If you have a steering position sensor which gives an output from 0-5v, and you log the voltage with the steering pointing straight ahead, you would expect the signal to be completely flat at 0v. If there is some noise on the signal, the signal might jump around between -0.1 and 0.1v. Noise is usually random, and, as such, can be decreased by averaging it over time. However, if the signal you are monitoring can change quickly, averaging the signal over a long period will remove some of the data. For digital signals, hysteresis is used to reduce the effect of noise.