Analogue Filters

Abstract

The term filtering has the commonly accepted meaning of separation—something is retained and something is rejected from the record being filtered. In electronic instrumentation signals are often filtered to improve the signal-to-noise ratio. As we have seen, signals are usually voltages, and in chapters 7 and 8 it will be shown that a signal can be made up from a large number of different frequency components. Usually only some of these frequency components are wanted. The others (which may interfere with the measurement) are removed by filtering.