Hi, looks quite useful! What's the benefit of the Xilinx CPLD (2-3 dollars/euro) over a PICDIV (<1 dollar/euro) ? Sync-input for the PPS-output would be useful. Also a PPS LED that blinks. If the PPS-divider is directly under the OCXO it will get more or less warm - could that be a problem?
What's the idea with the mixer/DIY-PLL? Did you look at PLL-chips instead? Would it make sense to have the time-constant for the PLL-loop adjustable with jumpers or a pot? Lock-indicator LED? Could the board be 100mm wide with all the connections on one 100mm side, to allow vertical rack-mounting ('plug-in' unit) in a 3U enclosure? here's a link to a similar-ish board, for comparison/inspiration: http://www.qsl.net/bi7lnq/distribution_amp/v1.5/10M_distributor.pdf cheers, Anders PS. use Kicad for your next OSHW design! ;) On Thu, Feb 25, 2016 at 5:25 PM, Gerhard Hoffmann <dk...@arcor.de> wrote: > HI, > > I have made some progress on my crystal oven carrier board. > > It will offer a home for one of these: > > - MTI-260 > > - Morion MV89A > > - HP 10811-611 > > > It provides regulated voltages for either of them, and the needed > electronics. > > It will be possible to lock the resident oscillator to an external > reference frequency, > > tune it a few Hz using a 10-turn-pot or an external tuning voltage from 0 > to 5 volts. > > The 10811 oscillator does not have a stable tuning reference voltage > output, it will be > > provided. > > There is a Xilinx Coolrunner 2C64 CPLD that generates a 1pps output from > the > > resident oscillator with the usual 20 us pulsewidth. > > The squarer that feeds the CPLD is either a LT6759-4 or my implementation > of > > C.Steinmetz's interpretation of C.Wenzel's version of the standard > differential limiter. > > The 1PPS can drive 3V3 CMOS, terminated with 50 Ohms. The output of the > CPLD > > is re-clocked in a 74LVC74 Flipflop directly from the limiting amplifier. > > There is a 1 stage common base isolation amplifier between the output of > the oscillator > > and the output of the board. It can be configured to work as a push-pull > active frequency > doubler without attenuation instead. There are 2 or 3 crystal notches to > remove the > closest (sub-)harmonics without affecting carrier phase stability. > > > Board size is abt. 100 * 110 square mm. > > The design is modular from predefined macros. You can cut it into pieces > and get: > > > 3 positive voltage regulators, LM317 style > > 1 negative voltage regulator, LM337 style > > 2 current feedback amplifiers using LMH6702 / AD8009 etc > > 1 ring mixer using a low 1/f noise Avago diode ring > > 1 PLL-regulator > > 1 isolation or frequency doubler amplifier > > 1 LT6759-4 limiter > > 1 Wenzel limiter > > 1 Xilinx 2C64 Coolrunner with pins on 100 mil grid > > 1 3V3-CMOS reclocked driver for 50 Ohm load. > > 1 input power meter > > > Connections to the modules are on a 100 mil grid, so one can > > rearrange/recycle everything on Vector board or such. > > This is open source hardware under BSD rules. > I do not intend to sell boards on a commercial base, > > maybe there will be some samples to get things started. > All parts are available from Digikey/Mouser. > > I'm currently doing the layout and will be trough with it in a week or so. > proposals, spotted errors, what to do with the empty space etc. are > welcome. > (but not on parts values, that will be taken care of later) > > circuits can be found under > > < > http://www.hoffmann-hochfrequenz.de/downloads/CrystalOvenCarrierBoard.pdf > > > > This is no product documentation but a quick snapshot as of this afternoon. > One thing that is missing is sync'ing on a 1PPs instead of the external > frequency reference. > > regards, Gerhard, DK4XP > > > > > _______________________________________________ > 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.