Wouldn't this be a natural application of a centroid or transition midpoint timing TDC implemented with a pulse shaper, fast ADC, and FPGA?
What about sampling inphase and quadrature sine waves? This should be more amendable to a microcontroller only solution and if I had to start working on something immediately, this is what I would try first. I assume in the earlier discussion Bruce mentioned these methods since they are included on his page of the various ways to implement TDCs: http://www.ko4bb.com/~bruce/TDC.html On Tue, 3 May 2016 08:40:53 -0700, you wrote: >HP/Agilent/Keysight laser interferometers >measure at the kind of rates you are talking >about and (last time I heard) could divide >an interference fringe down to 1/512 of a >wavelength. As you say, they definitely use >an ASIC with a ring oscillator. Perhaps >there is some way you could repurpose the >interferometer electronics to make your >measurement. > >You also might consider that over 25 years >ago, HP developed the 5313X counters with >interpolators implemented in FPGA's. The >FPGA's available now are vastly more >sophisticated and much faster. Perhaps there >is a way you do your ASIC in an FPGA. > >If you really do need an ASIC, the best way >to get that done is to partner with a university >and have some PhD student design it. Universities >often have arrangements to do this. > >Rick _______________________________________________ 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.
