Just long time i was interested, what means famous Atheros “periodic calibration” and “ANI”(adaptive noise immunity).
Many people give “voodoo” explanations, using their imaginations. Some telling it is temperature adjustment calibration, some is telling it is ACK calibration and etc.
Periodic calibration according to information i got from web (Atheros patents and source code of madwifi/ath5k):
1)In-band and Quadrature imbalance correction, which is important for SNR (not signal!).
as result of that (or just independent from that) channel noise floor correction/information.
Is it right? If yes - maybe better to add it to documentation.