[USRP-users] USRP1 and UHD rx_samples_to_file

Steven Clark steven.p.clark at gmail.com
Mon Nov 15 11:47:33 EST 2010


On Fri, Nov 12, 2010 at 10:41 PM, Steven Clark <steven.p.clark at gmail.com>wrote:

>
>
> On Fri, Nov 12, 2010 at 7:23 PM, Josh Blum <josh at joshknows.com> wrote:
>
>>
>>
>>> The amount of data written to the file is correct. HOWEVER, the output
>>> written to test.bin looks wrong. It is mostly in range [-4,4], with some
>>> large amplitude junk at the beginning of the capture. I don't see
>>> anything
>>>
>>
>> probably just noise
>>
>>
>>  resembling a sine wave. When I capture with the same input using
>>> GNURadio, I
>>> see a nice fat sine wave as expected. Any ideas?
>>>
>>>
>> was this with gnuradio + uhd?
>>
>>
> the working capture was with old (non-uhd) drivers.
>
>
>> do you have both slots populated on the USRP1? If so, the UHD may be
>> selecting the wrong board via some default behavior), can you try it with
>> one populated?
>>
>> try running the the ascii dft with the same options and see if the tone is
>> present.
>>
>> -josh
>>
>
>
> I had 2 WBXs in the USRP1, but regardless of which one I fed input to, UHD
> collect looked the same (low level noise + startup junk). I will try taking
> one WBX out / the ascii thing on Monday back at work.
>
> Thanks again for your patient help!
>
> -Steven
>

I tried removing one WBX and recapturing, and also using the ascii dft
program. None of these approaches showed my tone. And again, switching back
to gnuradio + non-uhd drivers worked fine (showed nice beefy tone). Any
ideas?

./rx_ascii_art_dft --rate=250e3 --freq=433e6
linux; GNU C++ version 4.4.4 20100630 (Red Hat 4.4.4-10); Boost_104100;
UHD_20101109.230702.c0dfc2c


Creating the usrp device with: ...
Using Device: Single USRP:
  Device: usrp1 device
  Mboard: usrp1 mboard - 4c7560d7
  RX DSP: usrp1 ddc 2X + hb
  RX Channel: 0
    RX Dboard: usrp1 dboard (rx unit) - A
    RX Subdev: WBX (0x0053)
  TX DSP: usrp1 duc 2X
  TX Channel: 0
    TX Dboard: usrp1 dboard (tx unit) - A
    TX Subdev: WBX (0x0052)

-Steven
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