Post by thread:[PIC]:Digital filtering using a PIC

Hello for all. I'm looking for way to do 60Hz BAND-PASS FILTER and 60Hz NOTCH FILTER using a PIC. Is it possible to do this with a PIC? Have you ever seen something like this? Thanks in advanced goes any help Luís Fernando -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Yeap ... it's possible.... .... try with the IIR filters algorithms of the embedded handbook. ---------------------------------------------------------- Ing. G. Quilosa Development Dept. ---------------------------------------------------------- ----- Mensaje original ----- De: antoniasse <.....antoniasseKILLspam@spam@BRAILE.COM.BR> Para: <PICLISTKILLspamMITVMA.MIT.EDU> Enviado: lunes 13 de agosto de 2001 9:01 Asunto: [PIC]:Digital filtering using a PIC Hello for all. I'm looking for way to do 60Hz BAND-PASS FILTER and 60Hz NOTCH FILTER using a PIC. Is it possible to do this with a PIC? Have you ever seen something like this? Thanks in advanced goes any help Lums Fernando -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

In article <001f01c123f4$6bb91a90$0101a8c0@desarrollo01>, Ing. Gustavo Quilosa <quilosabespam_OUTyahoo.com> wrote: > Yeap ... it's possible.... > .... try with the IIR filters algorithms of the embedded handbook. Doesn't that depend on the signal's sample rate? > De: antoniasse <@spam@antoniasseKILLspamBRAILE.COM.BR> > I'm looking for way to do > 60Hz BAND-PASS FILTER and > 60Hz NOTCH FILTER using a PIC. -- Harald Milz | KILLspamhmKILLspamlinux-magazin.de | If a messy desk stands Linux New Media AG | phone +49 (0) 89 993411-20 | for a messy mind, what Stefan-George-Ring 24 | fax +49 (0) 89 993411-99 | does an empty desk D-81929 Muenchen | http://www.linux-magazin.de | stand for ? -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

part 1 1641 bytes content-type:text/plain; charset=us-ascii for 60Hz notch... sample at an even harmonic frequency and average the result. Scott F. Touchton 1550 Engineering Manager JDS Uniphase Harald Milz <hmilz@LINUX-M To: spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU AGAZIN.DE> cc: Sent by: pic Subject: Re: [PIC]:Digital filtering using a PIC microcontrolle r discussion list <PICLIST@MITVM A.MIT.EDU> 08/13/01 12:12 PM Please respond to pic microcontrolle r discussion list In article <001f01c123f4$6bb91a90$0101a8c0@desarrollo01>, Ing. Gustavo Quilosa <TakeThisOuTquilosabeEraseMEspam_OUTyahoo.com> wrote: > Yeap ... it's possible.... > .... try with the IIR filters algorithms of the embedded handbook. Doesn't that depend on the signal's sample rate? > De: antoniasse <RemoveMEantoniasseTakeThisOuTBRAILE.COM.BR> > I'm looking for way to do > 60Hz BAND-PASS FILTER and > 60Hz NOTCH FILTER using a PIC. -- Harald Milz | hmEraseME.....linux-magazin.de | If a messy desk stands Linux New Media AG | phone +49 (0) 89 993411-20 | for a messy mind, what Stefan-George-Ring 24 | fax +49 (0) 89 993411-99 | does an empty desk D-81929 Muenchen | http://www.linux-magazin.de | stand for ? -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservmitvma.mit.edu with SET PICList DIGEST in the body part 2 3178 bytes content-type:application/octet-stream; (decode) part 3 136 bytes -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservEraseMEEraseMEmitvma.mit.edu with SET PICList DIGEST in the body

Hey Luis, We did somehting similar, you can have a look at my webpage. Look under filters, there's some files that may help (FIR implemenetaion, but should give an idea). (Though, I must say I dont think you really need to do this on a PIC!) Regards, S. Sinha (Saurabh) ---------------------------------------------------------------------------- ---- Tel: (012) 343-4912 Cell: 0825405577 Visit: http://home.mweb.co.za/si/sinha ['H'] Visit: http://ieee.up.ac.za/members/saurabhs ['W'] Visit: http://www.activesms.co.za/?sponsor=270825405577 [ActiveSMS, join me!] ICQ: 82010326 Alternative e.mail: RemoveMEssinhaspam_OUTKILLspammweb.co.za (if the auto-reply address doesn't work) {Original Message removed}

On Mon, 13 Aug 2001, Scott F. Touchton wrote: > > for 60Hz notch... sample at an even harmonic frequency and average the > result. > With the added benefit that you'll notch 30Hz, 15Hz, 7.5Hz, ... and in general 60/N Hz, including when N -> inifinity. In other words, you'll filter DC too! I'm not sure of the application, but you'll probably want to filter 60Hz by integrating over 1/60'th of a second time interval. For example, if you had a voltage to frequency converter as your A/D then you can count the pulses it emits for 16.6666 mSec. Or if you have a successive approximation A2D, then you could synchronously sample say 60*16 times per second and average the last 16 samples (add them together and then shift right 4) to get a representation of the signal minus 60Hz. Note that both of these suggestions are really low pass filters with a notch at 60Hz and not Notch filters per-se. Scott -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body

Hello Luis, Absolutely possible. We did a full elliptical filter on a processor with 20% of the Pic's power to filter flourescent light from an IR signal. You obviously already have the problem well in hand since you are dealing with a slow frequency. We used a commercial filter design package to determine coefficients and algorithms, then determined sampling rates that would a) be amenable to fixed point processing and b) allow some of the terms to drop out. Since most of the filtering work is done by multiplying finite values by trig functions, we used a lookup table to accomplish the multiply by a factor, then by a trig function. The result had virtually no gain in the pass band and an extremely fast drop off. Tom > {Original Message removed}

Sinha, you have a very nice theory here ! Just downloaded. Cheers, Vasile On Mon, 13 Aug 2001, Saurabh Sinha wrote: {Quote hidden}> Hey Luis, > > We did somehting similar, you can have a look at my webpage. Look under > filters, there's some files that may help (FIR implemenetaion, but should > give an idea). > > (Though, I must say I dont think you really need to do this on a PIC!) > > Regards, > > S. Sinha (Saurabh) > ---------------------------------------------------------------------------- > ---- > Tel: (012) 343-4912 > Cell: 0825405577 > Visit: http://home.mweb.co.za/si/sinha ['H'] > Visit: http://ieee.up.ac.za/members/saurabhs ['W'] > Visit: http://www.activesms.co.za/?sponsor=270825405577 [ActiveSMS, join > me!] > ICQ: 82010326 > Alternative e.mail: EraseMEssinhaspamspamBeGonemweb.co.za (if the auto-reply address doesn't > work) > > {Original Message removed}