FreeCalypso > hg > fc-rfcal-tools
comparison doc/Cable-config-howto @ 95:b68301b38ff2
doc: Cable-config-howto and General-flow written
| author | Mychaela Falconia <falcon@freecalypso.org> |
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| date | Mon, 17 Jul 2017 18:26:30 +0000 |
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| 94:b443d0665c1f | 95:b68301b38ff2 |
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| 1 One of the critical requirements for proper calibration of Tx power levels (and | |
| 2 of the Rx "magic gain" to a lesser degree) is that the insertion loss of the | |
| 3 cabling setup between your CMU200 and your DUTs (Calypso GSM devices to be | |
| 4 calibrated) needs to be precisely known and accounted for. Actually measuring | |
| 5 the insertion loss of your cables at the center frequency of each GSM uplink and | |
| 6 downlink frequency band with 0.1 dB accuracy is your responsibility; the rest | |
| 7 of this article will merely tell you how to feed these cable loss numbers to | |
| 8 FreeCalypso RF calibration tools. | |
| 9 | |
| 10 In our architecture the software component that takes care of adjusting the | |
| 11 power levels for the cable loss is fc-cmu200d; our fc-cmu200d reads the cable | |
| 12 loss numbers from a configuration file and instructs the CMU200 itself to | |
| 13 perform the actual adjustments. Furthermore, our architecture allows for | |
| 14 multiple cable configurations. Some Calypso GSM devices have SMA RF connectors | |
| 15 for attaching the antenna, in which case the calibration coax needs to terminate | |
| 16 in an SMA, others have MS-147 or Murata SWD/SWF RF test ports, in which case the | |
| 17 calibration coax needs to terminate in an MS-147 or Murata probe connector. If | |
| 18 you are working with different types of Calypso GSM devices, you will need to | |
| 19 switch between the corresponding cable setups, as the cable loss numbers will be | |
| 20 different for each setup: even if you keep the same "main" coax going from your | |
| 21 CMU200 to an SMA and add/remove Murata's SMA-to-SWD/SWF adapter at the end, the | |
| 22 addition or removal of that extra adapter will change the total insertion loss | |
| 23 along the full path, and this change needs to be accounted for. | |
| 24 | |
| 25 Cable configuration files are kept in the /opt/freecalypso/rfcal/cableconf | |
| 26 directory; it is up to you how you name your cable configs, but the following | |
| 27 convention is suggested: | |
| 28 | |
| 29 * If you have a cable setup that terminates in an SMA connector for calibrating | |
| 30 Calypso GSM devices with SMA antenna interfaces, the corresponding cable | |
| 31 config file should be named "sma". | |
| 32 | |
| 33 * If you have a cable setup that terminates in an MS-147 probe connector for | |
| 34 recalibrating Mot C1xx phones or similar, the corresponding cable config file | |
| 35 should be named "ms147". | |
| 36 | |
| 37 * If you have a cable setup that terminates in a Murata SWD/SWF probe for | |
| 38 working with devices like Openmoko GTA0x, the corresponding cable config file | |
| 39 should be named "murata". | |
| 40 | |
| 41 See cableconf-example for an example of the syntax, but please remember that | |
| 42 you are still responsible for putting in YOUR OWN numbers for the actual | |
| 43 insertion loss of your cable setups. | |
| 44 | |
| 45 When you actually run fc-cmu200d to begin a calibration session (see the | |
| 46 General-flow article), you will select the cable configuration to be used | |
| 47 by name with the -c option to fc-cmu200d. |