Cort, Yes your high to valley low will work as I stated in another reply. Has been used by Motorola years ago. Also the rec levels from different receivers can be different since one would be looking at a ratio.
73, ron, n9ee/r >From: Cort Buffington <[EMAIL PROTECTED]> >Date: 2008/06/20 Fri PM 03:57:47 EDT >To: [email protected] >Subject: Re: [Repeater-Builder] Re: Anyone familiar with the LDG RVS-8 Voting >system? > >Not quite enough of a programmer to take on the DSP, but will likely look at >the peaks and valleys with the ADC. I'm not sure why I'd need more than one >noise circuit though. I don't want to do a sample and hold, the ADC and >software can do that. I was thinking build one analog circuit and look for >valleys and peaks when the ADC reads the analog circuit output -- that is to >say, keep track of the highest level and lowest level over a certain very >short time period The highest high and highest low will indicate more noise >component? Yes? Am I missing the boat?</div><div><br></div><div>And for the >rest of the list, i can take this conversation with Jeff off-line if we're >putting out a bad S/N ratio (pun intended) >73 DE N0MJS >On Jun 20, 2008, at 2:11 PM, Jeff DePolo wrote: > > >> My exact issue when looking at S/N generators -- the analog >> part. Which is why I am about to build a 2-3kHz bandpass >> filter and switch to looking for low averaged values by less >> integration (shorter delta t) and faster sampling in the ADC >> to look for "valleys" in a "better" way. Make any sense at all? > >Yes, but you will have more immunity to audio level variations between >receivers if you do peak-and-valley comparison. Compare the ratio of peaks >to valleys rather than valley-only and you'll get a more >accurate<br>measurement of short-term S/N. Yes, you'll have two sets of >detectors for >each channel (one for peaks, one for valleys), and yes, you'll have twice >as<br>many inputs to mux into the ADC, but I think you'd end up with a >superior-performing product. Something to think about or tinker with. > >Of course, you could avoid all of the analog nonsense and do it with DSP, >that would be a cool project. Wish I had more time for these kinds of >projects... > >--- Jeff WN3A > > > --Cort BuffingtonH: +1-785-838-3034M: +1-785-865-7206 > > > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
