Phase noise measurements with the Koheron Alpha250

July 08, 2018

We released a new FPGA design for phase noise measurements.

Using a Koheron Alpha250, we compared the phase noise of 40 MHz signals from 3 different noise sources: a Red Pitaya STEMLab 125-14, another Koheron Alpha250, and a 120 MHz signal generator (Keysight 33622A):

Phase noise comparison

The higher phase noise of the Red Pitaya can be explained by the fact that the Red Pitaya DAC is clocked from a phase-locked loop inside the FPGA, instead of an external PLL.

The source code is available on GitHub for the Alpha250 and the Red Pitaya.