> The 5061 had an analog double integrator using a $100 op amp. > Maybe Hugh Rice can speak about that. You have to have the 2nd > integrator to prevent a ramping error term from turning into a > frequency offset instead of getting integrated out.
I never studied the control loop design on the 5061A/B. It worked just fine, so I didn’t dig into it. I’ll mention the $100 op-amp more in another story in the future, but it wasn’t nearly as exotic as it looks. I recall it being a hybrid circuit monstrosity – a whole bunch of discrete components all potted in blue plastic, and about 2” x 2” in size. My guess is that it was a high performance device, during the transition days from making op-amp with discrete parts on PCAs (like the 5060A did in the 1960s), to fully integrated op-amps in the 1980s. An awkward teen-ager of electronics from the early 1970s, so to speak. Modern IC op-amps probably could replace it just fine. Our super-technician/engineer on the production engineering team, Dave Montgomery, used to say we should replace it with and “Op-07”, his favorite high-end op-amp. It costs $.45 each now, if you buy 1000. Hugh From: time-nuts <[email protected]> On Behalf Of Richard (Rick) Karlquist Sent: Sunday, February 3, 2019 8:41 AM To: Magnus Danielson <[email protected]>; Discussion of precise time and frequency measurement <[email protected]> Subject: Re: [time-nuts] OCXO PLL gains? On 2/2/2019 3:06 PM, Magnus Danielson wrote: >> We also used a double integrator >> on the 5071A cesium standard, but cesium loops are NOT PLL's. > > Indeed, double-integrator in FLL is a separate class of problems. > > Didn't know it had double-integrator. > > Cheers, > Magnus The 5061 had an analog double integrator using a $100 op amp. Maybe Hugh Rice can speak about that. You have to have the 2nd integrator to prevent a ramping error term from turning into a frequency offset instead of getting integrated out. Rick _______________________________________________ time-nuts mailing list -- [email protected]<mailto:[email protected]> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com<http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com> and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
