Carnatic Pitch (CarnaticPith.xlsx see below) is based on the cycling of fourths (Ma-Derivation powers of 4/3) and fifths (Pa-Derivation powers of 3/2).
There are 12 notes of both Ma and Pa derivations. That makes 24 notes.
Sa is the base note which is equivalent to 1. Pa is fixed at 3/2 and is the 2nd made note.
Since there is only one variation of Sa and Pa there are 24 – 2 = 22 notes in total.
The Ma-Derivation notes have a dip in modulation.
The Pa-Derivation notes have a vibrato modulation.
Sa (1) and Pa (3/2) are the fixed base notes and have no modulation.