Hi Based on what I’ve seen off of eBay, a properly working surplus MV89A is a rare beast. The ones that are “ouch” to the touch do indeed have malfunctioning oven circuits. Out of a few dozen purchased I don’t think I found one that fully met the specs that it did when shipped. That easily could have been a function of only buying from the cheapest sellers …..
Bob > On Nov 19, 2017, at 11:40 AM, Vlad <[email protected]> wrote: > > > Hello, > > I am doing another fun project. It is data logger at this time. The "heart" > is MV89A OCXO and the "brain" is STM32. > "The box" has 1PPS input to control DAC which will control OCXO. BTW, this > M89A is pretty hot to touch. My other OCXO's not that much warmed. Is it > normal for this Morion model ? > I woul ask an advise regarding following issue. I have signal generator which > produce the square wave. The freq. is 192Hz. > > http://www.patoka.org/OCXO/LOGGER/IMG_20171119_104659813.jpg > > However, the logger measure it TWICE ! I think its because of that signal > form. Here is the output (in microseconds): > > http://www.patoka.org/OCXO/LOGGER/IMG_20171119_104838190.jpg > > In average delta is .0026041 s, which is almost equal to 384 Hz (192x2) > > For the input I am using the schema similar as HP was using in one of their > counters: > > http://www.patoka.org/OCXO/LOGGER/IMG_20171110_123201987.jpg > > > I tried another source (DDS sine generator, referenced from GPSDO) and that > beast produce exact number of events: > > 26.5404621 > 26.5473008 > 26.5525067 > 26.5577297 > 26.5629260 > 26.5681280 > 26.5733305 > 26.5785262 > 26.5837255 > 26.23559295 > 26.5941842 > 26.5993546 > 26.6045699 > 26.6097716 > 26.6149911 > 26.6202076 > 26.6254149 > 26.6306244 > 26.6358103 > 26.6410386 > 26.6462491 > > > However, it is some "spikes" in the data flow (see above the number > "26.23559295", which suppose to be something as "26.58..."). I can't > understand the reason for that. > The "delta" is .0052 s, which is almost equal to 192 Hz. But data flow is not > that "smooth" though. > > In square wave mode, "school grade" Wavetek generator produced exact 192 > events with no issues. (Except its output frequency is not that stable) > > 21.0578286 > 21.0630547 > 21.0682807 > 21.0735070 > 21.0787330 > 21.0839591 > 21.0891852 > 21.0944112 > 21.0996372 > 21.1048632 > 21.1100892 > > However, if I switch Wavetek to sine, my logger detected twice number of > event (384) > > 97.0185559 > 97.0214570 > 97.0237852 > 97.0266822 > 97.0290048 > 97.0319054 > 97.0342336 > 97.0371408 > 97.0394552 > 97.0423578 > 97.0446802 > 97.0475836 > 97.0499131 > 97.0527969 > 97.0551313 > 97.0580259 > 97.0603560 > 97.0632648 > 97.0655869 > > I would assume, some improvement needs to be done for the data logger input. > I am using 2N5485 and 74AC04 elements there. Any advises will be appreciated > ! Thanks ! > > > -- > WBW, > > V.P. > _______________________________________________ > 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.
