Analogue filters remain a quick cost effective solution to many signal related problems. Small noisy signals are often the cause of many problems in a complete range of measurement and control situations.
The simple rule " if you put in noise you will get noise in your data " applies, OR in simpler terms
"#!#! in , #!#! out"
Small Noisy Signals
A combined filter/amplifier near the transducer or signal source can greatly reduce problems. Especially where the signal cables are longer than a few meters (10's of feet). See the Kemo DIN Rail filters.
The classic use of filters, data acquisition requires that sampling rates must be higher then the data frequencies, or the system can start to 'see' alias frequencies that are not correct. Kemo filter response 01 is specifically designed for anti-aliasing applications.
Sometimes the small measurement signals are swamped by larger unwanted signals, filter out the unwanted before data acquisition and concentrate on the wanted part of the signal.
In many cases the bandwidth of the measurement or signals need to be limited, analogue filters are a quick easy way to achieve this.