Hi How many OCXO’s have you actually built?
Bob > On Jun 2, 2017, at 5:51 PM, Donald E. Pauly <[email protected]> wrote: > > # 2 is not true. A cut has either two turning points or zero. Where > both turning points exist there are two temperatures at which the > temperature coefficient of frequency is zero. Cut 0 on figure 6 at > https://coloradocrystal.com/applications has no turnover point. It is > neither fish nor fowl. Cut 6 is the normal AT curve with extremes of > ±16 ppm for -55° C thru +105° C. All curves normally intersect at 25° > C rather than the 27° C shown. 25° C is half way between -55° C thru > +105° C. Curve 6 is the Tchebychev polynomial y=4x^3-3x and curve 0 > is y=4x^3. > > Consider the standard AT cut which has turnover points at -15° C and > 65° C. The lower turnover would ordinarily not be used in ovens. A > set point error of ±1° C in the upper turnover point at 65° C results > in a frequency error of +14.875·10^-9. For cut 0, that same ±1° error > in room temperature results in a frequency error of ±31.25·10^-12. > This is an improvement of 476 to 1. You apparently have not thought > thru what improvements are possible with thermal coolers/heaters. > Among these is near instant warm up and greatly reduced power for > thermal management. > > πθ°μΩω±√·Γ > WB0KVV > > ---------- Forwarded message ---------- > From: Bob kb8tq <[email protected]> > Date: Fri, Jun 2, 2017 at 12:43 PM > Subject: Re: HP5061B Versus HP5071 Cesium Line Frequencies > To: "Donald E. Pauly" <[email protected]> > > Hi > > Which statement is not true: > > 1) That there is a tolerance on the cut angle of a crystal? > > 2) That true zero temperature coefficient only happens at the turn? > > 3) That heater based controllers are impossible to build? > > Bob > > On Jun 2, 2017, at 3:40 PM, Donald E. Pauly <[email protected]> wrote: > > That is not true. I say that thermal coolers have made ovens > obsolete. A zero temperature coefficient at room temperature is > easier to hit than a zero temperature at the upper turnover point when > such a thing exists. See > curve 0 in Figure 6 at https://coloradocrystal.com/applications/ . > > πθ°μΩω±√·Γ > WB0KVV > > > On Friday, June 2, 2017, Bob kb8tq <[email protected]> wrote: >> >> Hi >> >> Any real crystal you buy will have a tolerance on the angle. In the case of >> a crystal cut for turn >> the temperature will be a bit different and you will match your oven to it. >> If you attempt a zero >> angle cut, you will never really hit it and there is no way to compensate >> for the problem. >> >> Bob >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
