Hi audioguru,
Thanks for mentioning that. I do have to wonder however, why you
want to choose that filter response when it sounds like he wants to
filter the dc from a low frequency noisy input mixed with dc.
I could have misunderstood the application, but it seems to be that
we would want to reject all frequencies above dc as
well as possible and not attenuate any if possible. Forcing the
response to be -3db at the cutoff doesnt seem to have any useful
purpose for this app, again unless i misunderstood something.
He also didnt mention what kind of time profile he needed so i
didnt think that was important either.
BTW, there is another approach we have not talked about yet and
that is going totally digital (well almost). The implementation of
such would reduce the hardware requirement to one resistor and
one capacitor, regardless of the type of characteristic response
required.
This kind of implementation might require a bit more program code
memory but probably not a huge amount. A few calculations have
to be performed, usually done as part of the micro controller program.
Hi MrAL , thanks for the suggestion and also the previous one its useful . Actually I was unsure what to do to get a pure signal (DC) . The sensor I mentioned was Piezo (it not a raw sensor but a part of pressure sensor) . I measure fluid level with this sensor , which is outputting a proportional DC level at its outout. And when the vehicle moves the slosh imposes a DC output to flicker . Though I am doing other averaging technique whith my uC but still I am looking for how to make the output DC as smooth as possible. Also there is 5mV ripple imposed by the Pressure sensor.
I am having in my mind should I go as down as 2Hz-3Hz to correct this DC modulation due to sloshy environment.
audioguru , yes I require a low pass filter to smooth the DC as much as possible .
Steve, I will check what wrong I am doing as per simulation as you are getting it right!!
Regards
-Adi