I have to take the reading of two analog sensors temperature & Fuel level. Both of them are analog signal & i have to remove noise from this reading. And i want to use the Digital filter for these. My MCU is running at 32 MHZ, also i am taking reading of ADC for both the sensors every 5 msec.
Now i want to reduce Noise from my sample by using external analog filter & software digital fileter (IIR & FIR).
This link says we should follow Nyquist criteria for sampling to avoid alising problem. https://en.wikipedia.org/wiki/Analog-to-digital_converter
Now to design a Digital IIR filter, this link use to state about using cutoff frequency. https://stratifylabs.co/embedded%20design%20tips/2013/10/04/Tips-An-Easy-to-Use-Digital-Filter/
Now if i am right then Nyquist criteria & aliasing & setting sampling frequency is important for analog signals recording, where we are aware that human voice is < 20,000 HZ.
But how to set these criteria of (Analog or Digital filter cutoff frequency & sampling rate & nyquist criteria) for sensor signal like temperature & Fuel where we get simply the analog signals & we are not aware what frequency is for these signals.