wlan constellation calculation get different EVM result compare with result from API

[wei-smart]

Dear All,

Detail steps is listed below:

1. used rfic devm example:

2 measured EVM is less than -49

3.use constellation points for EVM calculation, the result is -44

I wanna get aligned EVM based on constellation, thanks.

[YouZi]

Hi Wei-Smart,

Could you offer more detail message about the issue?

Here is some question：

1, What's the RFmx version? 

2, What is the hardware setting?

3, The EVM getting from RFmxWLAN Property Node is different with the EVM caculated from constellation, right?

[MMargaryan]

Hi all.

And also, below you can find the link, full of information about NI RFIC System, Software and Hardware requirements.

NI RFIC

Regards,

Meri

[wei-smart]

Hey Youzi,

1.rfmx 1900

2.HW: 5840

3.Yes

Thanks.

[YouZi]

Hi Smart, 

Could you offer the example that you used?

Thanks.

[YouZi · Accepted solution]

Hi Smart,

The symbols used to calculate EVM are not guaranteed to be a 1:1 correlation with the symbols you see in the constellation map. 

In short, this might just be the way it is, and don't try to calculate on your own from the returned symbols, they are there for visualization only and not further processing.

And Where do the data come from? 

And the attached VI illustrating a significant increase in performance with a slight adjustment in your ideal symbol map.