I tried both of your suggestions – increasing RX gain and offsetting RX 
frequency. However, neither seem to be working.

 

Lenny

 

From: "Marcus D. Leech" <mle...@ripnet.com>
Date: Monday, July 16, 2018 at 10:08 PM
To: Leonid Veytser <veyt...@ll.mit.edu>, "usrp-users@lists.ettus.com" 
<usrp-users@lists.ettus.com>
Subject: Re: [USRP-users] Setting N310 TX and RX bandwidth

 

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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