Question about the occurrence of Tx saturation for DPD in ADRV9029

The Tx. signal level is going beyond the full scale value. You can reduce the digital input signal level by 2 or 3dB and increase the gain in analog signal chain to get the same Tx output power.

You can use CFR to reduce the peaks .

The possible reason for Tx signal saturation is due to PA compression due to which the DPD actuator is trying to compensate with the help of gain expansion. You might have to optimize the PA for better peak power which will reduce the gain expansion.

Which DPD model are you using and how did you pick this? Can you try doing model sweep and identify the best one? Follow the below link for more details.

wiki.analog.com/.../dpd_model_optimization

We scanned the DPD models (190 coefficient and 126 coefficient Model) according to the script and found the best DPD model currently (ADRV9025_DPD_126Coeff_Model_56).
However, after verification by DPD, the DPD Status Error Code displays the error message of Tx signal Saturation.
In addition, we reduced the digital signal by 3dB and then added the analog signal to obtain the same gain. However, after DPD calculation, the DPD Status Error Code still displays the Tx signal Saturation error message, as shown in the attached picture:

ACP without DPD                                                                    ACP with DPD                                                                        DPD Status

Hsinchu said:

In addition, we reduced the digital signal by 3dB and then added the analog signal to obtain the same gain. However, after DPD calculation, the DPD Status Error Code still displays the Tx signal Saturation error message, as shown in the attached picture:

I don't think you have reduced the digital signal power by 3dB as the Mean Tu power is same before and after reduction. Please check if you have really reduced it.

Also, apply CFR if required so the peaks will come down and the PA will be little more linear.

The digital signal has not been adjusted and the DPD state obtained by DPD calculation is as shown in the figure:

ACP without DPD                                                                             ACP with DPD                                                                                 DPD Status

Please reduce the digital input signal level by 3dB or optimise the PA for better peak power and/or use CFR so as to avoid the Tx Peak saturation error.