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+++ b/doc/RF-cal/Architecture	Sun Apr 23 18:01:17 2017 +0000
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+The RF calibration process fundamentally consists of 3 parts:
+
+1: The FreeCalypso GSM MS device under test (DUT) to be calibrated;
+
+2: An RF test station to which the DUT is connected via an RF coax cable,
+   performing the RF signal analyzer and signal generator functions required
+   for the calibration procedures;
+
+3: A program that communicates with both the DUT and the RF test station and
+   orchestrates all of the signal generation, measurement and computation steps
+   to arrive at the final calibration results to be stored in the flash file
+   system of the DUT.  The steps are too numerous, tedious and repetitive to be
+   performed manually, hence automation is required in order to make the process
+   practical.
+
+The goal of the FreeCalypso RF calibration subproject is to produce a set of
+tools for performing part 3 of the above breakdown.  The current vision is that
+our automated calibration software will be broken down into two interfacing
+components:
+
+1: There will be a Test System Interface Daemon (TSID) that encapsulates the
+   magic specific to a particular brand of RF test station, e.g., R&S CMU200.
+   The TSID will only talk to the CMU200 or other RF test station, but not to
+   the Calypso DUT, and the intent is that the TSID only needs to be started
+   once at the beginning of a calibration work shift and then stay running as a
+   hundred or more FreeCalypso GSM devices may be calibrated on the production
+   line.  The TSID will present a local socket interface (can be changed to
+   TCP/IP if operation over a network is required) to which the other component
+   below will connect as a client.
+
+2: There will be a set of 3 programs (fc-rfcal-vcxo, fc-rfcal-rxband and
+   fc-rfcal-txband) that perform the 3 required calibration groups for each
+   individual FreeCalypso device unit on the production line.  The production
+   automation script will need to run fc-rfcal-vcxo first, then fc-rfcal-rxband
+   for each of the hardware-supported bands (e.g., 900, 1800 and 1900 on
+   FCDEV3B-900), then fc-rfcal-txband for each of the same bands.  Each of these
+   programs will talk both to the DUT (via rvinterf) and to the RF test system
+   (via the TSID), i.e., will need to connect to an already-running rvinterf
+   process and to an already-running TSID via local sockets.
+
+The programs in the second group above will contain no knowledge specific to
+R&S CMU200 or any other particular brand of RF test station, instead this
+knowledge is to be encapsulated in the TSID.  The interface between the TSID
+and its clients will be of a command-response nature, and will be defined from
+the perspective of the needs of the FreeCalypso calibration process, rather than
+from the perspective of the capabilities of the CMU200 - in other words, the
+calibration automation program will command the TSID to the effect of "I need
+this", and it will be the responsibility of the TSID to figure out how to
+perform the required measurement or signal generation on the given type of test
+equipment.
+
+The details of the TSID socket interface remain to be defined.