[USRP-users] X310 External 10 MHz and 1 PPS specifications

Andy Walls andy at silverblocksystems.net
Tue Sep 23 17:58:11 EDT 2014

For the PPS in, 5V and 50 ohms (non-DC). See page 12 of the schematic which shows the 49.9 ohm resistor and a 1k/2k voltage divider.


Depending on the Vin min of the SN74AUP1T17 Schmitt trigger, you might be able to get away with something less than 5 V.


On September 23, 2014 5:28:32 PM EDT, "Kemp,	Elizabeth - 1008 - MITLL via USRP-users" <usrp-users at lists.ettus.com> wrote:
>Does anyone know what the input requirements are for the rear-panel
>external 10 MHz reference input and the 1 PPS input?
>I am using an OctoClock-G and will need to connect it to USRPs that may
>be as far away as 50 ft.  I'm trying to determine if the signal level
>at the USRP input will be sufficient.  The OctoClock-G output specs are
>typ. ~1.4 Vpp square wave for the 10 MHz output (50 ohm output
>impedance), and a 5V logic-level pulse for the 1 PPS output, according
>to the data sheet.
>USRP-users mailing list
>USRP-users at lists.ettus.com
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