diff doc/TI-docs @ 63:131abadbd74d

doc/Rx-cal-theory written
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 28 May 2017 03:21:34 +0000
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+We don't have a TI calibration document that exactly matches the
+Calypso+Iota+Rita chipset we are working with, but we do have two different
+documents from other points in TI history:
+
+ftp://ftp.freecalypso.org/pub/GSM/Calypso/rf_calibration.pdf
+
+https://www.freecalypso.org/LoCosto-docs/Production%20test%20and%20calibration/i_sample_rf_test_and_calibration_13_03_04_01991%20-%20v026.pdf
+
+The rf_calibration.pdf document we found back in 2011 dates from well before
+our Calypso+Iota+Rita chipset and describes TI's much earlier Sara RF, whereas
+the LoCosto document naturally deals with TI's LoCosto/I-Sample platform.
+
+To the best of our understanding of TI history, Sara RF is two generations
+before our Rita RF (as far as we know, the evolutionary line went from Sara to
+Clara to Rita), whereas LoCosto (combining the baseband processor and RF
+in the same chip) was a later development after the Calypso, hence our chipset
+and the corresponding TCS211 firmware fall right in between the two calibration
+docs we have.
+
+The details of the calibration procedures that are correct for our
+Calypso+Iota+Rita chipset and closely match those that have been performed by
+Openmoko's factory have been reconstructed by Mychaela Falconia after very
+careful scrutiny of both Sara and LoCosto calibration documents, combined with
+detective analysis of calibration artifact files found in Openmoko-made GTA02
+units; neither the Sara document nor the LoCosto one is particularly instructive
+by itself, and a *lot* of intelligent filling of the blanks was required.