Thanks for your reply.
I read your post, and based on that, I added logic to check the sign using the 14th bit (MSB) and apply appropriate adjustments. I also included the division by (2**11) as mentioned.
After that, I calculated the phase of the sample at the First Path Index (FP_INDEX) and compared it, only to find that there’s a noticeable discrepancy. I also computed the PDOA between STS_1 and STS_2 and observed that the result differed somewhat from the (PDOA / 2**11) value provided in the diagnostics.
I suspect this is because FP_INDEX refers to samples at 1 ns resolution, rather than the finer 1/64 ns resolution. As a result, the derived phase may be slightly inaccurate. I believe that if we compensate for the fractional part of the FP_INDEX as a phase shift, the result might align more closely with the diagnostics value. What do you think about this approach?