Hi Take a look at how the 60 MHz is generated. I believe that you will find that you have a sine wave that has come out of a logic gate via a low pass filter or that they square it up on the board already.
My *guess* is that you could fit a little board with a divide by 6 into the Rb and run it off of the device’s internal supplies. You would then have a 10 MHz unit. Bob > On Apr 27, 2015, at 5:34 AM, Bryan _ <bpl...@outlook.com> wrote: > > Bob: > > The output of the 60 and 20 MHz are sine waves. The 60MHz is very clean > whereas the 20Mhz is not. The ebay link has picture of the outputs and they > mirror my results. Thanks for the tip on the LT1763, probably better to use a > modified schematic of the one I posted and modify the circuit as I don't need > all the dividers, but it has the circuitry for the amplifiers and buffers as > well "wave shaping" the input. > > Cheers > > -=Bryan=- > >> From: kb...@n1k.org >> Date: Sun, 26 Apr 2015 09:56:17 -0400 >> To: time-nuts@febo.com >> Subject: Re: [time-nuts] Divider circuit for Rubidium Standard >> >> Hi >> >> I would *assume* that either the 20 or 60 MHz is already a square wave. If >> they both are, use the 20, if not use >> which ever one is a square wave already. >> >> Past that it is just a divide by 2 or a divide by 3 followed by a divide by >> 2. You want the last stage to be divide >> by 2 so the output is symmetrical. >> >> One of a multitude of possible divide by 3 circuits: >> >> http://www.indiabix.com/electronics-circuits/divide-by-3/ >> >> The divide by 2 would just be a D F-F with the inverted output tied to the D >> input. >> >> I would build it out of whatever fast modern logic is available. My >> preference would be for a +5 supply coming >> off of something like an LT1763 linear regulator. Buffers up the outputs >> with several inverters in parallel. >> >> Yes it’s not the ultimate super duper circuit. Done properly it will be >> about 100X lower noise than your >> Rb at Tau <= 10 seconds. >> >> Bob >> >>> On Apr 26, 2015, at 6:51 AM, Bryan _ <bpl...@outlook.com> wrote: >>> >>> All: >>> >>> Picked up a FE 5680B from Ebay awhile back. Appears to work fine, but is >>> limited to a 1pps output. However there is a point on the PCB that's >>> documented that has a 20Mhz output. There is actually a clean 60Mhz output >>> as well. >>> >>> http://www.ebay.com/itm/FEI-fe-5680b-rubidium-oscillator-With-1pps-20mhz-output-ONLY-10mhz-NEED-to-MOD-/291419889143?pt=LH_DefaultDomain_0&hash=item43d9fa9df7 >>> >>> I would like to tap this 20mhz output and feed it to a divider/buffer >>> circuit for a 10Mhz output at 50ohm. Can anyone recommend a good schematic >>> for such a purpose. I was looking at the project from David partridges web >>> site http://www.perdrix.co.uk/FrequencyDivider/index.html >>> >>> Cheers and thanks in advance. >>> >>> -=Bryan=- >>> _______________________________________________ >>> 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.
