Hi > On Sep 23, 2020, at 8:20 PM, Forrest Christian (List Account) > <li...@packetflux.com> wrote: > > I'm hoping some of the list are familiar with the newer currently-available > oscillators available from the distributors. > > Some background: > > I'm starting to play with a short-term 1PPS holdover application, mainly to > cover up brief GPS signal loss events (a few minutes at most).
Is “a few minutes” < 10? I’m guessing it is. > > Since I may at some point want to make numerous copies of this, I'd rather > start with a new oscillator as opposed to digging through the junkbox or > buying surplus. Lower cost (<$100 ideal, lower is even better) and power > consumption is good. My short-term stability requirements indicate to me > that I'm probably looking for an OCXO instead of a TCXO, although it looks > like some of the best TCXO's out there are in the range which will work in > most cases (50ppb over temperature (or better)). What is your holdover requirement in ns ? If 10 minutes is the max number, that’s 600 seconds. 1 ppb average error would be 600 ns. Is this to much? > > I suspect I'm going to handle the holdover in a FPGA. As such, I don't > think I'm going to bother trying to voltage control the oscillator. Seems > like it will make the overall circuit simpler and I don't have to worry > about a whole bunch of control circuit temperature compensation. Without knowing the holdover requirement there’s no way to really guess if this makes sense. A 2 ppm TCXO that costs < $1 can be steered with a $2 DAC. Steering it to < 0.1 ppb is not super crazy. To get 0.1 ppb out of a “static” device you would need a Rb rather than an OCXO. > > I've dug through enough datasheets at this point, my eyes are glazing > over. I also know that the spec sheets are only part of the story when it > comes to oscillators. I also have found over the years that often the part > I'm looking for (that 20ppb Temperature-stable TCXO for a reasonable price) > exists if you know the vendor to look at... > > So any specific recommendations or pointers toward a brand/type would be > appreciated. > Steer a TCXO …. Bob > -- > - Forrest > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.