On 07/16/2018 06:53 PM, Veytser, Leonid - 0665 - MITLL wrote:
Hi Marcus,
Thanks for your answer. Perhaps this is not my issue then. I am having
issue with sending and receiving a simple sine wave using N310. In the
simplest case, I can take X310 run txrx_loopback_to_file with the
arguments below, plot reals and imaginaries of the stored files and I
can see the sine wave. If I do the exact same command against a N310,
I appear to just see noise, which seems to be highly quantized. Just
values in the range between -4 and 4.
./txrx_loopback_to_file --tx-args
"addr=192.168.20.2,clock_source=external,time_source=external"
--rx-args
"addr=192.168.20.2,clock_source=external,time_source=external"
--tx-rate 1.25e6 --rx-rate 1.25e6 --tx-freq 1800e6 --rx-freq 1800e6
--tx-channels "0" --rx-channels "1" --wave-type SINE --wave-freq 1e3
Any help or suggestion is greatly appreciated!
Thanks,
Lenny
The gain-control range on the AD9371 is much larger than on cards you'll
find on the X310.
Try increasing the RX gain, and offset the RX frequency a bit -- you may
be losing some in DC-offset removal for a carrier that is right on top of
the "DC" region.
*From: *USRP-users <usrp-users-boun...@lists.ettus.com> on behalf of
"Marcus D. Leech via USRP-users" <usrp-users@lists.ettus.com>
*Reply-To: *"Marcus D. Leech" <mle...@ripnet.com>
*Date: *Monday, July 16, 2018 at 3:20 PM
*To: *"usrp-users@lists.ettus.com" <usrp-users@lists.ettus.com>
*Subject: *Re: [USRP-users] Setting N310 TX and RX bandwidth
On 07/16/2018 02:46 PM, Veytser, Leonid - 0665 - MITLL via USRP-users
wrote:
I am unable to set either RX or TX bandwidth on N310. When
attempting to set, I get the following warning:
Setting TX Bandwidth: 40.000000 MHz...
*[WARNING] [0/Radio_0] *set_tx_bandwidth take no effect on AD9371.
Default analog bandwidth is 100MHz
Actual TX Bandwidth: 0.000000 MHz...
and
Setting RX Bandwidth: 40.000000 MHz...
*[WARNING] [0/Radio_0] *set_rx_bandwidth take no effect on AD9371.
Default analog bandwidth is 100MHz
Actual RX Bandwidth: 100.000000 MHz...
When looking through the UHD code, I tracked down to these FIXME
comments:
https://github.com/EttusResearch/uhd/blob/master/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.cpp#L322
Is this some sort of limitation with the N310 and the AD9371
tranceiver? Does this mean I am unable to set TX and RX bandwidth
at all?
Thanks,
Lenny
Based purely on the comment, I'm guessing that there are notionally
registers to control this in the AD9371, but they don't apparently
work as documented, hence the warning message.
Keep in mind that *internally*, the AD9371 samples the analog mixer
outputs at several hundred MHz, so if the internal anti-alias filters
are set-up for 100MHz by default, there's no danger of aliases
appearing in the outputs, regardless of your ultimate sample-rate
delivered
to the host.
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