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diff --git a/host/docs/calibration.rst b/host/docs/calibration.rst new file mode 100644 index 000000000..14e66a312 --- /dev/null +++ b/host/docs/calibration.rst @@ -0,0 +1,61 @@ +======================================================================== +UHD - Calibration Application Notes +======================================================================== + +.. contents:: Table of Contents + +------------------------------------------------------------------------ +Self-calibration +------------------------------------------------------------------------ +The UHD comes with several self-calibration utilities for minimizing IQ imbalance and DC offset. +These utilities perform calibration sweeps using transmit leakage into the receive path +(special equipment is not required). +The results from a calibration are written to a csv file in the user's home directory. +UHD will automatically apply corrections at runtime when the user re-tunes the daughterboard LO. +Calibration results are specific to an individual RF board. + +**Note:** +When a calibration table is present, +and the user wishes to override the calibration settings through the API: +the user should re-apply the desired setting every time the LO is re-tuned. + +UHD comes with the following calibration utilities: + + * **uhd_cal_rx_iq_balance:** - mimimizes RX IQ imbalance vs LO frequency + * **uhd_cal_tx_dc_offset:** - mimimizes TX DC offset vs LO frequency + * **uhd_cal_tx_iq_balance:** - mimimizes TX IQ imbalance vs LO frequency + + +The following RF frontends are supported by the self-calibration utilities: + + * WBX transceiver board + * SBX transceiver board + * more to come... + +******************************************** +Calibration utilities +******************************************** +UHD installs the calibration utilities into <install-path>/bin. +**Disconnect** any extrernal hardware from the RF antenna ports, +and run the following from the command line. +Each utility will take several minutes to complete. +:: + + uhd_cal_rx_iq_balance --verbose --args=<optional device args> + uhd_cal_tx_iq_balance --verbose --args=<optional device args> + uhd_cal_tx_dc_offset --verbose --args=<optional device args> + +See the output given by --help for more advanced options, such as: +manually choosing the frequency range and step size for the sweeps. + +******************************************** +Calibration data +******************************************** +Calibration files are stored in the user's home/application directory. +They can easily be moved from machine to another by copying the "cal" directory. +Re-running a calibration utility will replace the existing calibration file. +The old calibration file will be renamed so it may be recovered by the user. + + * **Unix:** ${HOME}/.uhd/cal/ + * **Windows:** %APPDATA%\\.uhd\\cal\\ + |