Since firmware 2016.01-rc1 bladeRF has the ability to lock to an
external reference as well as produce arbitrary frequency signal
(25 MHz here) on its clock output.
Use gr-osmosdr source with the following arguments to produce 25
MHz on the SMB connector:
osmocom_fft -a bladerf,smb=25e6
To lock the bladeRF itself to an external GPSDO reference, use
additional arguments tamer=external for 10MHz or tamer=external_1pps for
1PPS GPSDO signals.
osmocom_fft -a bladerf,smb=25e6,tamer=external
The described method requires https://github.com/Nuand/bladeRF/releases/
Carefully *read the instructions for external reference locking*
(especially max allowed voltage levels) on Nuand's blog https://