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DBBC2 calibration

Modified 12:26, 13 Mar 2019 by ubach | Page History
    Table of contents
    1. 1. Calibration Procedure

    Version as of 16:26, 23 Nov 2024

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    - Everytime a new DBC firmware version is installed (PFB or tunable) the calibration parameters must be determined. -

    -  Calibration should also be repeated and checked whenever the Control Software has been restarted (especially when using the DDC mode)

    Calibration Procedure


    1) Inject a broad band noise signal into  all of the DBBC boards (e.g. use a splitter)

    2) Start the DBBC control software (PFB or DDC), confirm re-programing of the FPGA and wait until programming of the boards is finished

    3) Adjust the IF power levels to around 10000

    • PFB and DDC mode

    In the DBBC2 client manually set the attenuation (e.g. 40) until you reach a target of 10000 counts.

    dbbcifa=1,40,1

    Check the counts with:

    dbbcifa

    Alternatively you can let the AGC adjust the attenuation and set it to manual when the correct level is reached.

    dbbcifa=1,agc,1,10000

    Check the counts with:

    dbbcifa

    Once 10000 counts are reached just command

    dbbcifa=1,man,1

    Check again with :

    dbbcifa

    Change attenuation and repeat until the target has been reached. Repeat for all boards.

    • DDC mode only

    In addition for the DDC mode the AGC of the BBCs have to be turned of as well with:

    dbbcgain=all,20,20

    Typical BBC level is a few hundred counts. Check for some BBCs, e.g.

    dbbc01
Reply: dbbc01/ 598.0,a,16,1,man,20,20,385,418,0,0
dbbc05
Reply: dbbc05/ 598.0,b,16,1,man,20,20,354,387,0,0

    4) start the calibration

    •  PFB mode:
    calibration
    • DDC mode:
    calibration=all

    5) Update the configuration file

    A file containing the results is produced in c:\ (e.g. DATE-calib.txt) by the calibration command. Inspect or plot the DATE-calib.txt file and search for the minimum between the two peaks. Insert the minimum values into the configuration file e.g. c:\DBBC_CONF\dbbc_config_file_104.txt (file name varies depending on the version). Edit the line just above CAT2 entry. Please do not use the values reported by the calibration procedure itself that are printed in the command window. These are usually not between the two peaks.

    An example of for a calibration plot is shown below, as well as the script to produce such plots. Usage:

    calibration_plot.py BOARD_ALL-2019-009T160419-calib.txt

    to zoom into a specific region additional limits for x and y can be given: e.g.

    calibration_plot.py BOARD_ALL-2019-009T160419-calib.txt xlim=50,150 ylim=1500,3000

    In this case good phase values for all boards would be in the range 90 to 100.

    BOARD_ALL-2019-009T160419-calib.png