RX DC offset problem

We are using the AD9371 and seeing large and variable DC offsets, which have caused us to reduce the amplitude of incoming received signal to avoid clipping and distortion.

In addition this DC offset is causing unreliability in the recovery of our transmitted data.

Here is an example of the RX I,Q showing large DC offsets, clipping of the top of I and Q.

So from two perspectives we wish to remove the DC offset.

We have the DC_OFFSET initial calibration enabled which corrects for dc offset within the RX chain. There are no errors on initial calibration.

The AD9371 has DC offset removal at both the TX and RX sides, however these is very little information on how this works in detail in UG992 and if the settings can be optimised at all in cases where problems are seen.

In addition I have seen posts on the AD community forum for a different, but similar, AD361 transceiver. Here there is a known issue “DC offset correction algorithm fails sometimes whenever there is a signal very close to DC (less than 7.5 kHz)”.

https://ez.analog.com/wide-band-rf-transceivers/design-support/w/documents/10060/ad936x_5f00_dcoffset_5f00_issue

Can a more detailed explanation of how the DC offset removal works for the AD9371 TX and RX sides be provided?

Can an explanation be provided on how to use ADI SW APIs to optimise the DC offset removal?

Also does the AD9371 DC offset correction algorithm suffer from the “fails sometimes whenever there is a signal very close to DC” problem?

Also are the any other known issues with this function?

Regards

John