thanks for volentering sounds like you know what it takes to make a good one and set up the webpage.............. tom w0kgw
----- Original Message ----- From: "Dr Bruce Griffiths" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Saturday, October 21, 2006 7:20 PM Subject: Re: [time-nuts] The VE2ZAZ GPSDO > Tim Shoppa wrote: >> "John Miles" <[EMAIL PROTECTED]> wrote: >> >>> Some of the concerns may not be major issues (e.g., it seems safe to say >>> that the FLL action will correct for drift caused by the 7805's tempco, >>> unless you plan to dump a can of R134a on it), but others are worth >>> bringing >>> to the magazine's attention. If you'll forward your comments to Doug >>> Smith >>> at kf6dx (at) arrl.org, he'll most likely print them in the Letters >>> column. >>> >> >> Having seen some bad vibes unfold through the channels of the >> letters column and other communications with editors, I think that >> BY FAR the most useful thing to do would be to contribute an >> improvement (preferably with schematic) rather than a lengthy >> textual or mathematical criticism. >> >> Tim. >> >> _______________________________________________ >> time-nuts mailing list >> time-nuts@febo.com >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> > Since the disciplining technique is far from optimum, this may only > serve to further sidetrack the less knowledgeable from the best > engineering solution which can achieve a far better performance for a > similar cost. A comparison of the performance of this method with the > optimum method using similar receivers and crystal oscillators would > have been helpful in assisting newcomers in selecting a more appropriate > method. > > Perhaps someone should set up a webpage detailing how one should go > about disciplining a high stability crystal oscillator. > > Allan deviation vs tau for various GPS receivers > Allan deviation vs tau for various crystal oscillators. > Various phase measurement techniques and associated tradeoffs > Effect of various phase measurement techniques on the system Allan > deviation vs tau. > Filtering phase measurements and discarding outliers. > Choosing the appropriate loop time constant. > > Miscellaneous: > Use of synchronisers to reduce probability of generating runt pulses and > metastability problems. > Don't use same IC to buffer different frequencies > Resynchronising divider chain outputs to reference frequency clock to > reduce jitter. > > DAC requirements and tradeoffs > Monotonicity > Resolution > Noise > Short term stability > Cost etc. > > Monotonic high resolution DAC techniques > Multibit Audio DACs > PWM > etc. > > Bruce > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts