# How to calculate index table values in 28.0 format

Document created by BrettG on Jun 4, 2013
Version 1Show Document

The calculation of index values is described in application note AN-951, which is available here:

http://www.analog.com/static/imported-files/application_notes/AN-951.pdf

On page 11 you can find the formula for converting 28.0 index values to 5.23 values stored in RAM.

Just for everybody's reference, I've listed the first 50 index points in the table below.

 Index Value (5.23 format) 0 0 1 1.19209E-07 2 2.38419E-07 3 3.57628E-07 4 4.76837E-07 5 5.96046E-07 6 7.15256E-07 7 8.34465E-07 8 9.53674E-07 9 1.07288E-06 10 1.19209E-06 11 1.31130E-06 12 1.43051E-06 13 1.54972E-06 14 1.66893E-06 15 1.78814E-06 16 1.90735E-06 17 2.02656E-06 18 2.14577E-06 19 2.26498E-06 20 2.38419E-06 21 2.50340E-06 22 2.62260E-06 23 2.74181E-06 24 2.86102E-06 25 2.98023E-06 26 3.09944E-06 27 3.21865E-06 28 3.33786E-06 29 3.45707E-06 30 3.57628E-06 31 3.69549E-06 32 3.81470E-06 33 3.93391E-06 34 4.05312E-06 35 4.17233E-06 36 4.29153E-06 37 4.41074E-06 38 4.52995E-06 39 4.64916E-06 40 4.76837E-06 41 4.88758E-06 42 5.00679E-06 43 5.12600E-06 44 5.24521E-06 45 5.36442E-06 46 5.48363E-06 47 5.60284E-06 48 5.72205E-06 49 5.84126E-06 50 5.96046E-06

This FAQ was generated from the following discussion: How to calculate an RMS table values to select filter curves?