Jergen, I am glad to release every thing, there are no secrets if there is interest I will gladly send you and for that matter any one else interested off line schematics and pictures. I do not want to flood the list since there is only sparse interest also I am limited by the attachment size. If I find more interest I may put to gather a document package that I will send off line as an attachment. My only concern are the PC boards till we have a system running with software I may have to change layout and than some one may order one version and some one else the an other one. Also till every thing is cast in concrete the layout does not have components labeled. Presently I hand label on paper for those that get boards. If you want more please contact me off list with specific questions. As an example I have not been happy with the 100 MHz for the counters. On the last run I used a PLL using the reference channel. To many components and takes tuning. Found ICS 512 and thanks to Corby ICS 570. Takes two 512 or one 570. Finished layout yesterday for both and ordered parts for testing. Total cost still below $200. Bert In a message dated 8/22/2011 3:30:15 A.M. Eastern Daylight Time, j.bastemei...@tudelft.nl writes:
Dear Bert, Reading your description, did make me curious. I understand you don't want release too much in order to avoid confusion in the future. But do you have some more material you can share with us? Thank you, best regards, Jeroen On 08/19/2011 02:57 PM, ewkeh...@aol.com wrote: > Paul, > following all the responses to this posting I think a old fashioned D/M is > still the answer for you. For years there have been discussions on using > latest technology but limited to discussion no hardware. Maybe now is the > time it will change. > That is why two years ago I set out do develop a D/M system based on the > original NBS design but with its own counter and a cost goal of $ 200 and > readily available parts.. Thanks to Richard, Corby and Hubert there are now > eight systems out there with very good results. Cost goal was reached if 20 > PC board sets are purchased. The actual D/M right from NBS, more densely > packaged for better temp. tracking and later components. Corby's tests show a > noise floor of 1 E-13. Resolution is 1 E -15. I did post in the past a > picture but it is 115K, so off list I can send more info. > What is holding up the release is software that takes the counter outputs > and does the Allan deviation calculations and plots. > What is not included in the $200 is the offset Osc,, power supply and > outside enclosure. Depending on the OCXO used it will drive the total cost to > $300 even $ 400 if 10 Hz is used. But no counter needs to be used. > If you use a 1 Hz offset many choices for OCXO are available I have used an > Austron 1150 and more recently thanks to a lead from Hubert a Morion that > is available on ebay for $40. He characterized it with the D/M system. > If you want to use 10 Hz offset the only choice I know is the HP 10811. All > the ones I have can be mechanically moved at least + - 20 Hz. > I know nothing about the Keithly 776 so I do not know if it will work. You > may want to contact me off list. > The attached drawing of the counter (thank you Brian Kirby) gives you an > idea of my counter approach. It is $ 30 of the $ 200. Tipically the phase > between channel A and B are measured, but that creates times depending of > phase when the counter can not keep up because it needs time for processing and > transfer of data. My concept does also have such a counter but it is only > used to position phase or once a run is completed to pick a section where > channel A and B are in phase to eliminate any contribution by the offset > oscillator. Two counters each per channel count the 1 or 10 Hz frequency at > 100 MHz, resulting at 1 Hz with 1 E-15 and at 10 Hz 1 E-14 way better than > the D/M noise floor. The counters work in a ping pong mode so there is > continuous counting, I call it pseudo time stamping. It also allows you to "tune" > the unknown close to the reference at a 1 or 10 Hz rate. These four > counters are used for the Allan calculations. > This unit never needs a counter, once you connect Reference and PC you can > tune the offset exactly to 1 or 10 Hz, connect the unknown, "tune" it and > you are ready to go. PC interface is RS 232 or USB. > What is needed is some one tackling the PC software issue. > I will not get into the kit business. At one time I was considering to > coordinate a one time PCB run and even make some HP 10811's available since > thanks to Corby's testing, I have ten 10811 and 5071 HP OCXO's with better > than 1 E-12 over 1 to 100 sec..range, but after Jose Camara's comment that > is no longer an option for me. I will once a final board set has run with > software make all info available, and hopefully some one will pick it up. > The reason I am right now reluctant to release the PCB board code is if > changes need to be done it will be impossible to get rid of the previous code. > If any one wants go get involved software or hardware wise please contact > me off list. > > Bert Kehren > > > > In a message dated 8/17/2011 11:11:30 P.M. Eastern Daylight Time, > pa...@snet.net writes: > > Hello Folks, > I am looking for an instrument that is better than Fluke 103a comparator. > The purpose of this piece of equipment is help me learn more about > oscillators and characterizing them > > The HP5370B is the TIC I keep hearing about but I am not glued to that > make or model. > I wou;d like to hear suggestion from the group. > > Another way to go might be to build one of those units where there is a > common oscillator is split and feeds the LO of 2 mixers. > The RF side comes from the DUT and the REF > Sorry I cannot remember the acronym... MDMM???? > > I do have that Keithly model 776 Counter time with GPIB I am really fuzzy > on this aspect... > > Comments welcome > > Thank you > > PaulC > W1VLF > > > > From: To: Sent: > > > > _______________________________________________ > 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. > > > _______________________________________________ > 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. _______________________________________________ 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.