mirror of
https://github.com/saymrwulf/uhd.git
synced 2026-05-16 21:10:10 +00:00
61 lines
2.6 KiB
ReStructuredText
61 lines
2.6 KiB
ReStructuredText
========================================================================
|
|
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\\
|
|
|