Re: [Discuss-gnuradio] Failure of sending square wave over USRPs (back-to-back)

[Activecat]

I have found the answers.
http://nutaq.com/en/blog/multi-channel-synchronization-fpga-based-daq-systems
http://nutaq.com/en/blog/brief-overview-frequency-synchronization-ofdm

On the Nutaq platforms (ZeptoSDR, PicoSDR) you can control VCXO voltage
DAC from GNU Radio (and from FPGA user logic) to implement carrier
frequency offset correction.

Thanks everyone for your help.