Hello,
I am trying to tune the WBX to 60MHz, but everytime I do
I get an error. If I do it through usrp2_fft.py it says “Failed”,
if I do it through my c++ code, I get the error
set_rx_center_freq(6e+07) failed.
I used the u2_flash_tool to “burn” txrx_wbx.bin to the SD as follows:
sudo ./u2_flash_tool --dev=/dev/sdb -t s/w apps/txrx_wbx.bin -w
It appeared to work fine.
Also, Matt directed me to txrx_wbx.bin at
http://gnuradio.org/releases/usrp2-bin/trunk/
This is the one I used. I also “burned” u2_rev3.bin in a similar
fashion as above (sudo ./u2_flash_tool --dev=/dev/sdb -t fpga
u2_rev3.bin -w)
and it seemed to work fine. Got that from the same link above.
When I tune to freqs over 70MHz, everything seems to work, but
once I get around 68.5MHz, I get these errors.
Any ideas would be greatly appreciated.
I am using gnuradio-3.3.0-rc0.
Thanks,
Sharif
On Wed, Jun 2, 2010 at 3:54 PM, Sharif S. [email protected]
wrote:
Hello,
I am trying to tune the WBX to 60MHz, but everytime I do
I get an error. If I do it through usrp2_fft.py it says “Failed”,
if I do it through my c++ code, I get the error
set_rx_center_freq(6e+07) failed.
According to the driver, located at
gnuradio/usrp2/firmware/lib/db_wbxng.c, the minimum supported
frequency is 68.75 MHz, which makes sense since the ADF4350
synthesizer used on the WBX board only is spec’ed to run down to 137.5
MHz (and the quad demod chip on the WBX divides this in half
internally).
That being said, these VCOs can typically be tuned lower in frequency
(or higher) than the min/max frequency specs, but you’ll likely see
additional phase noise, and you’ll be running outside the expected
operating range of the chip, which is generally not ideal. But it can
be done.
–
John O.
CEO/System Architect
Epiq Solutions
On 06/02/2010 01:54 PM, Sharif S. wrote:
Any ideas would be greatly appreciated.
I am using gnuradio-3.3.0-rc0.
This was all fixed in the latest release, which is here:
http://code.ettus.com/redmine/ettus/projects/public/wiki/U2binaries
The gnuradio.org page is no longer being updated and should just have a
pointer to the new site.
Matt
On 06/02/2010 02:06 PM, John O. wrote:
frequency is 68.75 MHz, which makes sense since the ADF4350
synthesizer used on the WBX board only is spec’ed to run down to 137.5
MHz (and the quad demod chip on the WBX divides this in half
internally).
That being said, these VCOs can typically be tuned lower in frequency
(or higher) than the min/max frequency specs, but you’ll likely see
additional phase noise, and you’ll be running outside the expected
operating range of the chip, which is generally not ideal. But it can
be done.
No, we just tune to the lowest specified frequency for the VCO/PLL chip,
and the rest of the tuning is done using the DDC/DUC. Everything is
used within specs.
Matt
On Wed, Jun 2, 2010 at 4:29 PM, Matt E. [email protected] wrote:
set_rx_center_freq(6e+07) failed.
additional phase noise, and you’ll be running outside the expected
operating range of the chip, which is generally not ideal. But it can
be done.
No, we just tune to the lowest specified frequency for the VCO/PLL chip, and
the rest of the tuning is done using the DDC/DUC. Everything is used within
specs.
Right…I wasn’t implying that the driver for the WBX operates the
ADF4350 synthesizer outside of its spec’ed operating range, but I’ve
seen systems in the past that have taken this approach with
surprisingly good results (and of course lots of testing). But when
things break, you’re typically on your own.
The DDC/DUC approach is certainly cleaner, and does the job.
–
John O.
CEO/System Architect
Epiq Solutions
On Wed, Jun 2, 2010 at 14:05, Matt E. [email protected] wrote:
The gnuradio.org page is no longer being updated and should just have a
pointer to the new site.
This is done.
Johnathan