Hi,

when I started receiving mail from th piclist I saw the last messages
from a thread concering averaging or calculating the meanvalue.

because I missed almost all messages I hope somebody can give some
suggestions. My goal is to controle a Motor with PWM, and to have an
information about speed, I will measure the back emf.

My 1st problem is the measured backemf. the signal variies according to
the rotation of the aramture. Using a analog low pass filter deigned for
the also required low speeds leads to problems with higher speeds.

Motor pwm should be done with fixed length pulses length approx.
5..10ms, pause varies due to increasing repeatition of the pulse for
higher speeds.

My Idea is to "filter" the backemf by variing the rate the backemf is
sampled and "averaging" the measured values. Because I4m not the best in
"inveting weels" I would like to get some opinions, tips, hints.

Thanks in advance,

        Stefan Sczekalla-Waldschmidt
        ssw@oikossw.de