nRF52832 + sgtl5000 wireless audio

[enukic]

Hi, I'm trying to set up wireless audio stream using 2 nRF52832 Dev Kits and SGTL5000 audio boards.
SDK: nRF5 SDK 17.1.0
For the wireless protocol I've used ESB, and the program is based on SDK ESB Tx/Rx examples, alongside with this example from NordicPlayground Github:

https://github.com/NordicPlayground/nRF52-teensy-sgtl5000-audio

Audio stream works, and the latency is decent, although I'd like it to be less (15-20ms).
But the issue for me is when I measure input and output signal with an oscilloscope (where input is a sine signal), the output signal's phase is always slowly shifting.

I am attaching Tx and Rx projects.

Does anyone know what could be the issue here? Is there a way to address it?

Thanks a lot!
Emir

nrf_sgtl500_esb_audio.zip

[enukic]

Thanks for the support on this. Unfortunately, I wasn't able to solve this issue up to this point.
If you seem appropriate, please close this ticket. I think I have hit a dead end with this one.

Thanks
Emir