Monday, February 27, 2017

Reduce Noise in Your Sensor Measurements with an Active Low Pass Filter Part 1

In this three part series we look at how to design a signal conditioning circuit to increase the accuracy and resolution of your ADC measurements. The signal conditioning circuit consists of a double pole active Sallen Key Low Pass Filter and a non-inverting op amp. The filter portion is meant to attenuate high frequency noise from your sensor signal to increase measurement accuracy. The amplifier portion scales the signal up to the full range of the ADC to ensure you are getting max resolution.




You can find the online filter calculator used in part one at this link: http://sim.okawa-denshi.jp/en/OPseikiLowkeisan.htmk

You can access the LTspice file on Github at: https://github.com/ForceTronics/Sallen-Key-Low-Pass-Filter-Design/tree/master

Sallen-Key Low Pass Filter Circuit with Amplifier Stage in LTspice