Hi Bernhard,
yes the API is wrong, it should say:
FP_AMPL1 = this is the amplitude of 3rd point after CEILING (FP_INDEX)
FP_AMPL2 = this is the amplitude of 2nd point after CEILING (FP_INDEX)
FP_AMPL3 = this is the amplitude of 1st point after CEILING (FP_INDEX)
The DC offset estimation is not available.
The SQRT approx = MAX(Q, I) + 1/4 MIN (Q, I), where Q and I are absolute values of real and imaginary parts of complex sample.
Regards,
Zoran