--- a/doc/Tx-cal-theory	Tue Feb 13 02:25:27 2018 +0000
+++ b/doc/Tx-cal-theory	Tue Feb 13 03:18:38 2018 +0000
@@ -66,31 +66,25 @@
 level for each band reduced by 0.8, making it 32.2 dBm for EGSM and GSM850 and
 29.2 dBm for DCS and PCS, while all other levels are set to the spec numbers.
 
-In my own experience with getting the Tx power levels calibrated on our current
-FCDEV3B boards, our hardware is able to hit all of the lowest spec power levels
-with good margin (the APC DAC value never goes below the 60-70 range), hence
-the low targets did not need to be shifted, but the highest spec power level
-could not be achieved in every band.  Following TI's practice with LoCosto, I
-set the highest power level target to 32.2 dBm for the EGSM band and to 29.2 dBm
-for PCS, but I was consistently able to get the full 30 dBm out in the DCS band,
-hence I set the DCS band highest power level target to the official number of
-30 dBm.  It needs to be emphasized, however, that these results are quite
-specific to our current flock of FCDEV3B hardware, and your results will most
-likely be different if you are working with a different hw design such as a
-non-FreeCalypso derivative of Openmoko's GTA02 design.
+The calibration that was performed by Openmoko's factory (FIC?) on their GTA02
+units is similar to what the old Sara document calls for: the highest power
+level is set to 31.8 dBm for EGSM or GSM850 and to 28.8 dBm for DCS and PCS,
+the next one down is 30.5/27.5 dBm instead of 05.05-spec-given 31/28 dBm, and
+for the lowest 4 (EGSM or GSM850) or 6 (DCS and PCS) power levels the decrement
+between levels is 1.5 instead of 2, putting the lowest EGSM or GSM850 power
+level at 7 dBm instead of 5 dBm, and the lowest DCS and PCS power levels at
+3 dBm instead of 0 dBm.
 
-Update: the above calibration observations for the FCDEV3B should be held
-doubly in doubt because the calibration status of my CMU200 itself is in
-question, i.e., it is not currently known if the measurements it reports are
-really trustworthy.  After the above paragraph was written, I replaced the
-Rx/Tx module inside my CMU (the original one was good for Rx, but the Tx side
-was dead), and after this internal module replacement the power measurements
-reported by the instrument are 0.5 dB less than what it reported before.  Which
-raises the questions: are the new measurements low by 0.5 dB relative to the
-real truth, or were the old ones high by 0.5 dB relative to the real truth?  Or
-is the real truth something else altogether?  Until we raise a LOT more money
-to get this CMU200 properly calibrated, we are limited to guesswork and the
-true transmitter behaviour of our FCDEV3B hardware remains unknown.
+It appears that OM/FIC were using some TI-provided calibration software without
+taking the time and effort to tune its settings for their own hardware: when we
+recalibrate these OM-made devices in our own lab, we are able to hit all of the
+highest and lowest power levels given in the GSM 05.05 spec.  On our own FCDEV3B
+hardware we are likewise able to get the full 30 dBm in the DCS and PCS bands,
+but we are not able to get the full 33 dBm in the low band.  Following TI's
+practice with LoCosto, I set the highest power level target to 32.2 dBm for the
+EGSM and GSM850 bands; for DCS and PCS the highest power level target is 30 dBm
+per the spec.  On the low end the power level targets are the official ones
+from the GSM 05.05 spec.
 
 Profiles for Tx levels calibration
 ==================================
@@ -99,19 +93,19 @@
 power levels for each band requires a preconfigured txlevels calibration profile
 for each band as one of its inputs; if you are performing calibration on
 individual units of a board design for which the correct profiles have already
-been crafted, you simply use those given profiles (fcom1 for our current flock
-of FCDEV3B boards), but if you are doing Tx power level calibration on a new
-board design for the first time, you first need to characterize the Tx output
-level behaviour of your new board design and craft the appropriate set of
-profiles.
+been crafted, you simply use those given profiles (see the txlevels directory
+in the source tree for our current offerings), but if you are doing Tx power
+level calibration on a new board design for the first time, you first need to
+characterize the Tx output level behaviour of your new board design and craft
+the appropriate set of profiles.
 
 The profiles for txlevels calibration reside in /opt/freecalypso/rfcal/txlevels;
 each per-band profile is sought in a file named profile_name-band_number, where
 profile_name is the profile name argument given to fc-rfcal-txband and
-band_number is one of 850, 900, 1800 or 1900.  For example, the profile set for
-our current FCDEV3B hardware is named fcom1 ("FreeCalypso hardware, Openmoko-
-based, version 1"), this hw platform is 900/1800/1900 MHz triband, and the
-individual profile config files are fcom1-900, fcom1-1800 and fcom1-1900.
+band_number is one of 850, 900, 1800 or 1900.  For example, if you are using
+the rf3166-ideal profile set (appropriate for recalibrating Openmoko GTA02
+devices), the individual profile config files are rf3166-ideal-900,
+rf3166-ideal-1800 and rf3166-ideal-1900 for the tri900 band configuration.
 
 Each profile provides two key pieces of data: the list of fixed APC DAC values
 to be used as the basis set for constructing the piecewise linear model, and
@@ -141,8 +135,8 @@
 CMU200) really matches the numbers you have put in your cable configuration file
 (see Cable-config-howto).  If you fail to ensure these prerequisites, your
 fc-rfcal-txbasis observations will be meaningless, as the cable insertion losses
-are typically of the same order of magnitude as the transmitter differences you
-are trying to determine.
+and instrument errors are typically of the same order of magnitude as the
+transmitter differences you are trying to determine.
 
 You will need to run fc-rfcal-txbasis with a guesstimated set of APC DAC values,
 to be revised iteratively, and get a feel for what your DUT is putting out.