Just an idea -- if 440 Hz would work, there are a lot of electronic tuning fork circuits out there.
Here is one: http://www.spaennare.se/tfork.html You could choose another crystal frequency or divide-by ratio if it needs to be 400.00 Add a phase-shift circuit to get the other two phases (if needed), amplifiers and you are good to go. Dave > -----Original Message----- > From: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] On Behalf Of b...@lysator.liu.se > Sent: Thursday, March 28, 2013 05:48 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] OT - DC-10 gyros > > Hi Bill, > > > Well, I can come up with something topical, read on. :) > > [snip] > > > Topical in a more abstract way, strapdown systems really are very > > interesting. They require precise integration of the rate > output over > > time to derive velocity and position, and really weren't > practical until > > the 70's when small enough computers existed to do the requisite > > calculations. (I worked on the nav system for the Trident > missile back > > in my Draper Labs days). > > Well, for the analysis of your gyro performance, time-nuts are already > equiped with one of the tools used - the Allan Variance. > > http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4404126&tag=1 > > There is also the relation > > GPS & oscillator -> GPSDO > > where in the navigation field > > GPS & 3x gyro + 3x accel -> GPS stabilised inertial > navigation > system > > > -- > > Björn > > > _______________________________________________ > 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. _______________________________________________ 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.