Paul take your time we may be in the psec. arena but that does not require instant response. Putting a D/M in front of your present counter is an answer, but once the PC software is done on my unit it is a better solution because it is a totally stand alone system and if you build my D/M it will cost you $ 180 in parts if 20 order a board set the counter components only add $ 20! Boards, mixers amps and transformers make up the cost. I will be glad to sell you a D/M board at cost. All D/M boards are basically the modern adaptation of a circuit the NBS presented in 1975 and issued as a paper in 76. I was there! Like every body else I only updated the selection of parts. The counters are unique. Bert In a message dated 8/23/2011 1:49:58 P.M. Eastern Daylight Time, pa...@snet.net writes:
Hello Bert, I apologize for this very late response to your email. To be totally honest I didn't really understand what you were talking about. I am new at this and didn't realize I had on hand some of the equipment I needed to do some basic testing. My counter timer will resolve down to 2 nanoseconds, in a 1 sec interval. Which is not near good enough for what I want to see. Using a piece of undisturbed coaxial cable as a time delay I was able to Using TimeLab, with lots of help from John Miles, and reading " A Small DMTD System," by Bill Riley I now have a basic.... basic understanding of what you were talking about. Using a piece of undisturbed coaxial cable as a time delay from A to B I was able to run a test with the Z3801 as the ref. and find in 1 sec the best I can do is 1.74 Nsec in a 1 second ave. Also I ran the same test at 100 Khz , 1 MHz and 10 Mhz with the traces overlaying and they was almost no difference at all It appears like I have a number of options: 1) Buy a 5370A/B 2 Build/Buy a DMTD system 3 Put a DMTD in front of my current counter. Since I have a counter that interfaces correctly with TimeLab, I would prefer to go with #3 So yes can I see the larger picture and more about the DMTD system you mention. Thank you Bert. Paul A. Cianciolo W1VLF http://www.rescueelectronics.com/ Our business computer network is powered exclusively by solar and wind power. Converting Photons to Electrons for over 20 years -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Friday, August 19, 2011 8:58 AM To: time-nuts@febo.com Subject: Re: [time-nuts] any HP 5370B Available or other TIC 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.
