From: Leon Heller Subject: Re: TECH: Filter on the output signal of a reciever Date: Thu, 31 Oct 96 22:11:09 GMT Message-ID: <846799869snz@lfheller.demon.co.uk> Organization: Home In article <32774E4B.2F1C@nlr.nl> Hilbrink@nlr.nl "Niels Hilbrink" writes: > I was wondering if anybody has ever tried to put a noise filter on the > output signal of tracker (Polhemus Fastrak) ? <...> > * Has anybody ever used a filter? > * What kind of filtre was used, Kalman, Wavelet Transform, Fast Fourier > Transform, etc. ? > * What is the effect of the filter on system latency ? Where I used to work we also had this problem with the Polhemus tracker. I recorded some of the data and had a go at analysing it (FFT, etc.), but it appeared to be random, and therefore very difficult to deal with. It seemed to be a lot less troublesome early in the morning and late at night, when everything else was switched off. We had a student implement a Kalman filter as a degree project, but the additional lag would have been excessive. I don't think it would have worked, anyway, given the nature of the interference. Leon -- Leon Heller, G1HSM | "Do not adjust your mind, there is E-mail leon@lfheller.demon.co.uk | a fault in reality": on a wall Phone: +44 (0)118 9471424 | many years ago in Oxford.