[time-nuts] SE880 GPSDO

[Ilia Platone]

Thank you Attila,

Just for informations, as I must build the board from scratch, does this 
design is good to implement into the datalogger?
I mean, for the second RTK purpose, does this u-blox module satisfy my 
requirements (link below)?
http://www.opendigitalradio.org/lea-m8f-gpsdo

Regards,
Ilia.

Il 26/04/2016 01:36, Attila Kinali ha scritto:
> On Mon, 25 Apr 2016 23:34:52 +0200
> Ilia Platone <info at iliaplatone.com> wrote:
>
>> I selected this because of the CMOS output, since I didn't find any
>> Connor Winfield osc with these levels yet.
> To get to CMOS levels, you usually add a simple inverter, with an
> capacitor in front and a 1M resistor across the inverter (from input
> to output).
>
>
>> Actually  want to achieve less than around 78ps jitter at 125MHz. (this
>> should be achievable using this also:
>> http://www.digikey.it/product-detail/it/fox-electronics/FVXO-HC53B-125/FVXO-HC53B-125-ND/2153894)
> I think you are mixing up a few things here:
>
> Your logger might have very relaxed jitter requirements, but the
> GPS module needs a low noise reference signal. If you feed it with
> the noisy HC53 output, you will degrade your GPS receivers performance
> severely. At the minimum, you should use a normal XO for the GPS modul.
> You can of corse use a HC53 as the reference for your logger if its
> jitter is ok for you.
>
> And for comparison, for a XO you usually talk about jitter in the
> order of 100fs to 1ps (10kHz-20MHz)
>
>
>
> 			Attila Kinali

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