AnsweredAssumed Answered

FMCOMMS5, how to get phase coherent RX channels with IIO Oscilloscope?

Question asked by ta2otd on May 21, 2018
Latest reply on May 22, 2018 by ta2otd



I want to see the phase coherence in FMCOMMS5, by using the IIO oscilloscope application.

I see the coherence in the channels which belong to the same AD9361, but couldn't manage to see the coherence between the channels in different AD9361's. I used a signal source at 2.4 GHz as an input to the RX ports.


I understand that I need an LO that can feed both AD9361's at the same time, and I shouldn't use their own LO's.


In the FMCOMMS5 controls tab, in the RX settings, I see the "external LO" checkbox, I understand that this external word means that is external to the AD9361 but internal to the FMCOMMS5 (Is it?). When I activate this checkbox, I don't see the sine pulses, it looks like external LO waits something that is not in my setup. For this, I checked the boxes in the ENSM/Modes/Clocks tab, it says "XO disable, Use Exrefclk" and "Ext RX LO" , however, I couldn't manage to obtain the sine pulses I've injected.


Also, I see the ADF5355 in the back side of the hardware physically.

Does external LO means this chip? If it is, how to activate this chip?


And one more question about the Advanced/FMCOMMS5/Cal Switch Control: When I click to calibrate from one TX channel to the other RX channel, what happens? I did this, but nothing has changed, I couldn't get phase coherent channels.


Have a nice monday,