Exporting Ref Out From Pps In Port On Usrp X410 Using Uhd Python

Updated Apr 29, 2026

Environment

Hardware

  • Ettus USRP X410

Programming Language

  • Python

The USRP X410 includes a PPS IN connector that is primarily intended for accepting an external pulse‑per‑second (PPS) signal. However, this port can also be configured to output a reference clock signal (Ref Out). This capability is useful when synchronizing other USRPs or external equipment using the X410 as a clock source.

Follow these steps to enable Ref Out on the PPS IN port of a USRP X410.

1. Import the UHD Python Module

Ensure UHD is installed on your system and import the uhd module in Python.

import uhd

2. Create a USRP X410 Object

Instantiate a MultiUSRP object using the address of your USRP X410.

args = "type=x4xx, addr=<USRP IP ADDRESS>"
usrp = uhd.usrp.MultiUSRP(args)
Replace the USRP IP ADDRESS with the address assigned to your device.

3. Enable the Reference Clock Output

Configure the device to output the reference clock through the PPS IN port.

usrp.set_clock_source_out(1)
This call enables the reference clock output, allowing the PPS IN port to function as a clock output instead of an input.

Related Links

Other Support Options

Ask the NI Community

Collaborate with other users in our discussion forums



Request Support from an Engineer

A valid service agreement or active software subscription may be required, and support options vary by country.