Forum: GNU Radio UHD Announcement - November 16th 2011

Hello list,

Recall from my previous announcements that addition of correction
registers and API for DC offset and IQ balance. Well, now you can use
special calibration utilities that come with UHD to improve RF
performance for WBX and SBX better than the out of the box specs.

So, I just merged these self-calibration utilities into the master
branch. These utilities can be used to minimize IQ imbalance and DC
offset through calibration adjustments. The calibration is automatic,
just run the utils, correction factors are saved and applied at runtime.

Currently, only SBX and WBX are supported. The utilities will not run on
USRP1, because it lacks the necessary FPGA fabric. More details and
instructions for how to use can be found here in the application notes:
http://files.ettus.com/uhd_docs/manual/html/calibration.html

If you plan on using the IQ balance calibration utility, I recommend
grabbing the latest images from here. Basically, these new images have
some tweaks to the dynamic range of the correction registers.
http://code.ettus.com/redmine/ettus/projects/uhd/w...

Happy calibrating,
-Josh

Hi
I am trying the calibration programs on my USRP2 with WBX board and they 
all give an error:

Error: RX dboard has empty serial!

The verbose output is below.
Thanks for your effort this will really help my application.

David


tempest@ubuntu:~/Documents$ uhd_cal_rx_iq_balance --verbose
linux; GNU C++ version 4.4.3; Boost_104000; UHD_003.004.000-65b6acc


Creating the usrp device with: ...
-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes
RX IQ: 78.749809 MHz: best suppression 69.127581 dB, corrected 13.330759 
dB
RX IQ: 86.049870 MHz: best suppression 68.840208 dB, corrected 15.483059 
dB
RX IQ: 93.349931 MHz: best suppression 68.952237 dB, corrected 16.616805 
dB
RX IQ: 100.649992 MHz: best suppression 67.945456 dB, corrected 
17.176162 dB
..............
..............
RX IQ: 2173.849206 MHz: best suppression 69.625957 dB, corrected 
39.116919 dB
RX IQ: 2181.147741 MHz: best suppression 69.841937 dB, corrected 
39.452520 dB
RX IQ: 2188.449328 MHz: best suppression 69.643630 dB, corrected 
39.248418 dB

Error: RX dboard has empty serial!

Hi
Figured it out myself WBX didn't have serial number in eeprom so I used

usrp_burn_db_eeprom to create it.

Thanks Josh great calibration utillity


tempest@ubuntu:/usr/local/share/uhd/utils$ ./usrp_burn_db_eeprom 
--id=0x0052 --unit=TX --ser=146
linux; GNU C++ version 4.4.3; Boost_104000; UHD_003.004.000-65b6acc

-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes
Reading TX EEPROM on A dboard...
  Current ID: WBX (0x0052)
  Current serial: "146"
  Current revision: ""
  Done

tempest@ubuntu:/usr/local/share/uhd/utils$ ./usrp_burn_db_eeprom 
--id=0x0053 --unit=RX --ser=146
linux; GNU C++ version 4.4.3; Boost_104000; UHD_003.004.000-65b6acc

-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes
Reading RX EEPROM on A dboard...
  Current ID: WBX, WBX + Simple GDB (0x0053)
  Current serial: "146"
  Current revision: ""
  Done