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]

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.

[zyan]

7180.zephyr.hex

Hi, Jonathan

Thanks for your replay.

1. We measured at the output of SMA connector.

2. We use the commands from wifi radio test, here is an example about how we test  G mode in channel 2412.

wifi_radio_test init 1
wifi_radio_test tx_pkt_tput_mode 0
wifi_radio_test tx_pkt_rate 54
wifi_radio_test tx_power 18
wifi_radio_test tx 1

3. Sure, here is the version of my build environment, and I upload the radio_test 's .hex file for 5340DK & 7002EK if you need it.

[JONATHAN LL]

Thanks! have forwarded internally and will update when i have something. 

[JONATHAN LL]

Hi zyan ,

1. Our measurements in product spec are taken at the output of RF. Please compensate for PCB losses or any other losses between RF pin and SMA connector.

2. Get power measurements without issuing tx_power command (i.e., wifi_radio_test tx_power 18 in your command sequence below) . This will provide measurements with default tx power settings. Use NCS 2.7.0 codebase for these measurements.