Dennis J. Murray wrote: > I'll tell you guys - I've been following this link since it's > inception and you REALLY have my curiosity piqued!! I've used TDRs > quite a bit in a past life and I DEPENDED on the visual > representation on the screen to interpret what is really on the line! > I don't think I EVER had a clean line that didn't require some > interpretation - was that hiccup a sharp bend? water in the line? an > unauthorized tap? A long-forgotten splice? etc. > > How do you plan to accomplish this using a PIC or an oscillator > circuit???? Or don't you? Just looking to determine overall length > to the most significant reflection?? > > ----- Original Message ----- > From: "michael brown" > To: > Sent: Thursday, February 20, 2003 10:33 AM > Subject: Re: [PIC]: How would I build a reflectometer? > > >> From: "Michael Rigby-Jones" >> To: >> Sent: Thursday, February 20, 2003 5:47 AM >> Subject: Re: [PIC]: How would I build a reflectometer? >> >> >>>> There might be some way the pulse transit time on the cable might >>>> be made into a sort of oscillator circuit. >>>> >>> That's basicaly what Wagner suggested a few posts back. I was >> thinking you >>> could perhaps do away with pulse reflections all together and just >>> use cable capacitance with some calibrations for cable type. It >>> might be able >> to be >>> made accurate enough for some applications, but TDR is the way to >>> go for real accuracy. Oh, now I got the mistake. In the lack of time, I thought he was trying to measure the time a pulse would take to cross a certain distance of certain wire. I didn't get the idea of checking problems in the transmission media. Of course, echo image analysis is "a must" to understand what is happening. The same problem in the media, with different types of cables can show different answers, so... Wagner. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu