Ettus B100, UHD, Fedora18

[Youri Westerman]

Hi all,

I'm trying to transmit a DAB signal by using mmbTools and an Ettus B100 using the UHD driver on Fedora18.
So far I have succesfully build the opensource software (crc-dabmod, crc-dabmux). First I tried the GNU/Radio and UHD driver from the fedora repo (installed through yum). But on the UHD mailinglist I was told to use the GNU/Radio build script so I have done that.
After setting up the software environment I've used DabAudio WAPP (http://mmbtools.crc.ca/content/view/14/29/) to generate an ETI file, which succeeded and I received in my mailbox.
Now because I'm using the UHD driver I read here I needed a different base band player. So I'm using this one: http://www.opendigitalradio.org/index.php/UHD_Band_3_baseband_player as Matthias posted in another message.
I modified it adding: type=b100,master_clock_rate=32768000,num_send_frame=128 to the DeviceAddr field of the UHD USRP sink.
Using crc-dabmod ~/Downloads/archive_1366212706_360558.eti -l -g1|~/Documents/coinwap_uhd_full3.py -r2048000 I start the process and it does not crash. However when specifying send_frame_size= things get really unstable (I have found that 2048 is a good value for me).
However it states that there is no resampler:
-------------------------------8X--------------------------
Input
  Name: /home/mds/Downloads/archive_1366212706_360558.eti
Output
  Name: /dev/stdout
  Sampling rate: 2.05 mHz
Input file format: framed
Input file length: 21150004
Input file nb frames: 25000
No resampler
linux; GNU C++ version 4.7.2 20121109 (Red Hat 4.7.2-8); Boost_105000; UHD_003.005.002-52-gf01d1a28

Using Volk machine: ssse3_64
-- USRP-B100 clock control: 2
--   r_counter: 25
--   a_counter: 0
--   b_counter: 256
--   prescaler: 8
--   vco_divider: 2
--   chan_divider: 25
--   vco_rate: 1638.400000MHz
--   chan_rate: 819.200000MHz
--   out_rate: 32.768000MHz
--

UHD Warning:
    The requested decimation is odd; the user should expect CIC rolloff.
    Select an even decimation to ensure that a halfband filter is enabled.
    decimation = dsp_rate/samp_rate -> 33 = (32.768000 MHz)/(1.000000 MHz)

UHD Warning:
    The requested interpolation is odd; the user should expect CIC rolloff.
    Select an even interpolation to ensure that a halfband filter is enabled.
    interpolation = dsp_rate/samp_rate -> 33 = (32.768000 MHz)/(1.000000 MHz)
>>> gr_fir_ccf: using SSE

(python:24483): Gtk-CRITICAL **: IA__gtk_widget_get_direction: assertion `GTK_IS_WIDGET (widget)' failed

(python:24483): Gtk-CRITICAL **: IA__gtk_widget_get_direction: assertion `GTK_IS_WIDGET (widget)' failed

UHD Warning:
    The requested decimation is odd; the user should expect CIC rolloff.
    Select an even decimation to ensure that a halfband filter is enabled.
    decimation = dsp_rate/samp_rate -> 33 = (32.768000 MHz)/(0.992970 MHz)
UUU
-------------------------------8X--------------------------

Furthermore it gives warnings about the decimation and interpolation. The problem here is that I'm unable to pick up the signal on the receivers.
The reason I'm doing this is because I'm working on a system that will make a lot of use of Slideshow. So after getting this working I'll have to find a way to use crc-slideshow on a much newer os than it was build for.
My apologies for I am a bit of a newbie on this topic. Does anyone have some pointers on why I might not receive a proper signal on the receivers? (Samsung Galaxy S, Sensa Pure). What about those warnings and the No Resampler notification?

Kind regards,

Youri

[Youri Westerman]

Photo of the hardware

[Matthias P. Braendli]

Hi Youri,

On 19. 04. 13 14:15, Youri Westerman wrote:
> Furthermore it gives warnings about the decimation and interpolation.

You don't have to be concerned about this warning per se, it was added
quite recently in UHD, but I'm surprised it shows samp_rate = 1MHz.

If your sample rate on the USRP really is 1MHz, then it cannot work. But
I see you specify -r to coinwap, which surprises me

> ~/Documents/coinwap_uhd_full3.py -r2048000

Maybe that is something to be investigated. But it's just a guess.

Good luck,

mpb

[Youri Westerman]

Hi Matthias,

Any clues on how to determine what the sample rate really is? When changing the sample rate in the grc file I get the same result.

Furthermore after the first 2 warnings and the notification that it'll start using SSE the sample rate changes. But I can never get the value above 1MHz. Should I try resolving this problem on the USRP Users mailinglist?

So the "No Resampler" notification would be displayed because the input file already is the appropriate sample rate?

Thanks for your time.

Youri

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[Matthias P. Braendli]

Hi Youri,

have you set the master_clock_rate=32768000 option ?

If I recall correctly, it's essential if you want to use the native
sample rate (2048000 samples per second)

I have no other hints right now besides that...

mpb

> <mailto:crc-mmbtools%2Bunsu...@googlegroups.com>.

[Youri Westerman]

Hi,

Just to let you all know, I managed to solve the problem by using mbuffer in between crc-dabmod and coinwap. The underruns were causing the signal to be unavailable for short periods of time.

Kind regards and thanks for the assistance,

Youri

[Phil Roberts]

Dear Youri & all,

 

I have an almost identical problem with recent acquired B100 Bundle and working along with latest Ubuntu, I have installed the latest GNU Radio / companion along with CRC-DabMod & Matthias UHD Base Band Player which I have modified to include settings for the B100 as follows: type=b100,master_clock_rate=32768000,num_send_frame=128

 

The system runs with the following : crc-dabmod ~/Downloads/ocean-waves-1_1378736624_862422.eti -l -g1|~/Downloads/coinwap_uhd_full3.py -r2048000

 

The B100 shows a steady A light and the graphical GUI shows a good plot but I am not receiving any DAB signal.

 

After starting the terminal output shows the following errors :

 

UHD Warning:
    The requested decimation is odd; the user should expect CIC rolloff.
    Select an even decimation to ensure that a halfband filter is enabled.
    decimation = dsp_rate/samp_rate -> 33 = (32.768000 MHz)/(1.000000 MHz)

UHD Warning:
    The requested interpolation is odd; the user should expect CIC rolloff.
    Select an even interpolation to ensure that a halfband filter is enabled.
    interpolation = dsp_rate/samp_rate -> 33 = (32.768000 MHz)/(1.000000 MHz)
>>> gr_fir_ccf: using SSE

UHD Warning:
    The requested decimation is odd; the user should expect CIC rolloff.
    Select an even decimation to ensure that a halfband filter is enabled.
    decimation = dsp_rate/samp_rate -> 33 = (32.768000 MHz)/(0.992970 MHz)

 

 

I did try to add  "send_frame_size=1023" to the UHD Device Addr field but the system fails to start    

 

I also tried adding mbuffer as you have posted but still no receivable DAB compliant signal.

 

Would you have any other suggestions please? & did you ever resolve the sample rate error?

 

Kind Regards

 

Phil

 

 

 

 

[Youri Westerman]

Hi,

You should try using mbuffer and setting the send_frame_size to 1024 or any other power of 2, so if you start at 1024 just multiply by 2 and try 2048, if that fails do the same thing. That's the way I got it working eventually. Though not on all receivers.

Good luck and I guess a tool like sdr-j comes in handy for doing at least the measuring of a signal.

Youri

--

[Phil Roberts]

Thanks Youri,

 

All working well now including DAB+ using Tipok's codec, in the end it was the send frame size causing problems.

 

Regards

Phil