NI RF Phase-Coherent Multi-Channel

[Betty Boop]

Hello! I would just like to ask why I'm getting the results shown in the attached file in using the NI RF Phase-Coherent Multi-Channel.

For all frequencies, I'm using the same demo program (included in NI RF Phase-Coherent Mulit-Channel) for the generation and acquisiton.

Generation: NI-RFSG Phase-Coherent Multi-Channel Generation Example

Acquisition: NI-RFSA Phase-Coherent Multi-Channel Acquisition Example

The desired results are those under the 1GHz frequency. However, I'm working on 915MHz. Needless to say, I can't see any pattern in the behavior of the plots when increasing/decreasing the frequency. That's why I really can't understand the results I'm getting.

Please help me.

Thank you very much for your time! 🙂

[Jonathan_S1]

Hi,

Thanks for contacting us about this.  Can you give us a little detail about your hardware setup?  It would be helpful if you could describe all of your connections, or even better, provide a photo of the setup.  Additionally, can you provide screesnshots that show your software settings, as well as the data in question?

Thanks,

Jon S

[Betty Boop]

Hello!

Attached are pictures of the hardware set-up. It is identical to the typical 2-channel phase-coherent RF signal generation and acquisition set-up.

This thread is same as http://forums.ni.com/t5/RF-Measurement-Devices/RF-Synchronization-Suite/m-p/1893713#M1995.

The software I’m using is suggested by Andy on post no.2 in the link above. I’m trying to generate a CW with 915MHz carrier frequency. However, I get incorrect plots when I use 915MHz. Setting the frequency to 1GHz results to correct plots. This is without changing any setting in the front panel.

The main problem when I use 915MHz is that one channel moves faster compared to the other channel. For example, in the IQ plot, there would be 2 points representing the 2 channels. These points travel in circular path. If the slower channel travels 1 complete circle, the faster channel is able to travel more than 1 circle. Moreover, the phase delta is not constant since one channel moves faster than the other.

More on this in the link above.

Thank you very much for your time! I really appreciate it. 😄