The Error Vector Magnitude (EVM) performance of the Nordic7002EK in the 5G frequency band is not good

[zyan]

Hi all,

I am using the Nordic 7002 EK board with the Nordic 5340 DK board.

When I conducted the production testing (using IQ xstream), I found that for TX-HT-MCS7 in the 5520 channel, the TX power was 14.5 dB but the EVM was only about -20 dB (usually it is about -27 dB).

I checked the OTP area to see if I could decrease the TX power to improve the EVM, but only the MAC address or the CALIB can be changed.

Is there anything I can do to improve it or is this the limit for the EVM test?

Thanks & regards

[JONATHAN LL]

Will look in to this and provide more info later on. 

Can you share what NCS version you are using? 


Regards,
Jonathan

[zyan]

Hi,Jonathan

Thanks for your quick reply. I used the radio_test sample and my NCS version is 2.6.0.

[JONATHAN LL]

Hi,

Can you test with NCS 2.7.0 RC2 (latest main)? This should hopefully solve the issue. 

Regards,
Jonathan

[zyan]

Hi,

Sorry for the late reply, We tried 2.7.0 SDK but do not solve the problem. Could you please let us know if this board has registers that store power amplification values? So we can reduce the EVM value by lowering the power.

Thank you!

[JONATHAN LL]

Will look in to this and see what other options you can test as well, will update when I have more info. 

Regards,
Jonathan

[JONATHAN LL]

Hi,

Can you share more info for us to reproduce: 

1. Test results with latest NCS (2.7.0 rc) - please specify the NCS SHA used in your testing

2. Test setup, NCS sample used for testing and detailed test procedure will really help us understand better (hopefully all cables used are calibrated?)

3. Can you share the hex file that you are using for nRF5340DK+nRF7002EK board?

4. Any VSA EVM measurement plots will be very useful.

[zyan]

3312.zephyr.hex

Hi, here are the details about the power and EVM values I measured with the 2.6.0 SDK and the 2.7.0 RC2 SDK, along with the .hex file I used.

[JONATHAN LL]

Thanks, I will have forwarded the info to our experts and will update you if we need anything more or have some results or comments. 

Regards,
Jonathan

[responsible_duck]

Hi JONATHAN LL just to add, we are seeing similar behavior (unrelated to the original poster or project). 

[JONATHAN LL]

Can you (responsible_duck ) create a new ticket here on Devzone? Link to this ticket as well in that new ticket and we will follow up.

[JONATHAN LL]

Hi zyan , 

1. All our measurements refer to output of RF pin. Are the power numbers measured (by you here) refer to output of RF pin? Or measured at the output of SMA connector?

2. What is the command sequence used for these measurements? Please share the command sequence.

3. Please confirm that hex shared by customer is built with NCS release 2.6.x codebase.