TSW14J58EVM: TX IQ data wrap around problem using TRF1208-AFE7950EVM

Örjan Eriksson

Part Number: TSW14J58EVM

We are using the TSW14J58EVM and TRF1208-AFE7950EVM and have connected a RF loopback from TXA to RXA.

Latte v2.5 is used for setup and playback and capture of IQ data.

The problem we have is that there is a wrap around issue in the playback of IQ data. Playback of the IQ data buffer is not seamless, there is a discontinuity in the TX data.

When the TX IQ data wraps around from the end of the IQ data buffer to the start of the buffer there are 2 samples missing.
In the image below the data wrap around point is at x=101 so there seem to be some filter effects involved as well.
The TX IQ data is loaded using the command <setupParams.FPGA.sendCustomComplexData(0,filePath + fileName)>.

How can we solve this problem?

over 2 years ago

0 Camilo Garcia Trujillo over 2 years ago

TI__Expert 5185 points

Hi Örjan,

We will set up to test this in the lab and reach out to the team that designed the FW for the TSW14J58 to check this. We hope to have some results by the end of this week / beginning of next week.

Best,

Camilo

0 Camilo Garcia Trujillo over 2 years ago in reply to Camilo Garcia Trujillo

TI__Expert 5185 points

Hi Örjan,

We have set this up in the lab and observe something similar to what you have described. Where there seems to be a discontinuity in the TX when using this function.

We will reach out to our software team for a fix.

Best,

Camilo

0 Camilo Garcia Trujillo over 2 years ago in reply to Camilo Garcia Trujillo

TI__Expert 5185 points

Hi Örjan,

After reviewing how we were testing the function yesterday we noticed that the discontinuities we were seeing were not because of the sendCustomComplexData itself but because of our IQ data. Because we were using a cw tone that did not fit within the samples in an integer number of periods.

A couple of questions:

Would it be possible for you to share the waveform you are trying to send? We can do this through email if you would prefer.
Could you elaborate on the sequence that you are using for this loopback test? Like what commands you are running after bringup?

Best,

Camilo

0 Örjan Eriksson over 2 years ago in reply to Camilo Garcia Trujillo

Prodigy 10 points

Sure, I have gathered the required files including my setup scripts. Contact me by email and I will make sure you get them.

So, what I do is bring up the system, apply my configuration script, download the TX IQ data, and then capture the received IQ data using the FPGA_CPLD section.

I also apply a rectangular window by process.fft.window=0 but that should not affect the captured and saved IQ data.

0 Camilo Garcia Trujillo over 2 years ago in reply to Örjan Eriksson

TI__Expert 5185 points

Hi Örjan,

I have reached out to you through email. I will close this post so that we can continue the discussion through email.

Best,

Camilo

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TSW14J58EVM: TX IQ data wrap around problem using TRF1208-AFE7950EVM