That was on my mind when I suggested a sampling phase comparator with the sampling time adjusted for noise rejection. Of course since I have been doing a lot of research recently on sampler design, every problem looks like a nail. :)
Thyristor commutation into a reactive load can be nasty but I have heard horror stories about inverters as well. On Sat, 23 Feb 2013 14:05:36 -0500, Peter Gottlieb <n...@verizon.net> wrote: >Some grid connected inverters have a LOT of noise around the zero crossings, >so >much so that certain digital power meters won't function as they can't get >frequency lock. I've seen this on the large Parker units as well as the low >bid >units out of China. So if you have solar or wind farm alternative energy >projects nearby you may indeed see excessive noise. > >Excess noise and high order harmonics from such inverters has on occasion >caused >capacitive line filters on nearby equipment to overheat and catch fire. > >Peter > >On 2/23/2013 7:53 AM, Didier Juges wrote: >> "I am curious how this compares with the zero crossing method." >> I suppose it should work much better because this method will not be so >> sensitive to noise around the zero crossings. It will use the entire >> waveform. >> >> Didier >> >> Sent from my Droid Razr 4G LTE wireless tracker. >> >> -----Original Message----- >> From: Gabs Ricalde <gsrica...@gmail.com> >> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> >> Sent: Fri, 22 Feb 2013 9:01 PM >> Subject: Re: [time-nuts] Logging the grid frequency.... >> >> Hello, >> >> I also don't have a Picotest or similar equipment but I've done similar >> things by using the line input of a soundcard. Multiply the recorded >> signal with a 60 Hz quadrature oscillator, apply a low pass filter then >> do some analysis on the resulting phasor. The stability of the sound >> card oscillator should be enough for this purpose. >> >> You can measure the frequency difference w.r.t. the 60 Hz oscillator by >> taking the slope of the phasor angle (be careful with phase wraparounds) >> and you can do this as often as you like. I'm curious how this compares >> with the zero crossing method. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
