David Marmoy | 24 Oct 11:19 2014

Fwd: out-of-tree module config.h documentation/use


I am writing an out-of-tree module and have used the gr_modtool to generate the module and block skeletons. All the block source files include a config.h file, but I have not been able to find documentation of its use or location anywhere. 

Does anyone know what it is used for and how?

Thank you, 

David Marmoy
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Stefan Oltmanns | 23 Oct 19:37 2014

Latest Gnuradio git won't compile on OS X

I just got the latest git version of gnuradio and tried to compile, but
I get compilation errors resulting from avxintrin.h:


These errors seems to be common and result from using non-standard
GCC-extensions that clang does not support.

Any ideas?
Simone Ciccia S210664 | 23 Oct 16:43 2014

Get a pointer to UHD "Source" from other block in flow graph

How to get a UHD USRP SOURCE OBJECT within my own block ?
  -  I already instantiate an UHD USRP SOURCE in the flowgraph and I want a
pointer within my own block to read parameters. 
  -  Also, which is the effect of creating two times a new USRP SOURCE
block by using "uhd::make(address)" with the same IP address in different
blocks of the flowgraph?

I read from the manual that it is possible to control UHD Source/Sink by
sending commands.
In the case of Source block, are the loops admitted in GNURadio by using
PMTs asynchronous messages for write back parameters?

Tom Rondeau | 23 Oct 16:35 2014

Free shipping for GNU Radio gear!

I've just been informed that the store we use for GNU Radio merchandise (in the US) is having free shipping next week on orders of $30 or more.

Check out our store:

And if you see anything you like, here's the info on the free shipping promo:

 - Free standard shipping for orders of $30+
 - Valid: October 27th – October 30th, 2014
 - Coupon Code: VAMPIRE14
 - Cannot be combined with other discounts or coupon codes


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Daniel Camara | 23 Oct 16:20 2014

Building a Zedboard BOOT.bin


  I am trying to generate a bootable SD card for the zedboard and I am running over some small issues. For starters, do you provide the u-boot.elf you use somewhere? In the http://gnuradio.org/data/sdk/zedboard_armv7a-hf-vfp-neon/ there is only the uboot.bin, but the boot.bif at zynq-acp/top/zedboard/boot requires the .elf.

  I tried to build everything as described in the "Building the Linux Kernel, U-Boot, & Root Filesystem with OpenEmbedded" section but then... I run into  MANY issues  building it, (really many,  I am writing down everything and, if I manage to do it fully one day, I already promised I will  contact the write all the issues and I will try to contact the responsible for the module to share my findings, it may help the next people :). For the moment I got stuck at:
configure:18748: error: in `..../oe-repo/build/tmp-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/libxt/1_1.1.4-r0/libXt-1.1.4':
configure:18750: error: The pkg-config script could not be found or is too old.  Make sure it
is in your PATH or set the PKG_CONFIG environment variable to the full
path to pkg-config.

Alternatively, you may set the environment variables XT_CFLAGS
and XT_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.

To get pkg-config, see <http://pkg-config.freedesktop.org/>.
See `config.log' for more details


| ERROR: Function failed: do_configure (log file is located at ..../oe-repo/build/tmp-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/libxt/1_1.1.4-r0/temp/log.do_configure.19545)
ERROR: Task 3409 (.../oe-repo/oe-core/meta/recipes-graphics/xorg-lib/libxt_1.1.4.bb, do_configure) failed with exit code '1'


  Any ideas? I looked into the libxt_1.1.4.bb to see what I could change... but as  I never used bitbake nor have I ever create a recipe... I am afraid of breaking something if I just disable it.

  By the way, is there any chance some one will try to adapt the ISE scripts to vivado? The XPS tool, used in the scripts, does not exist anymore :(. I installed  the evaluation version to create the fsbl.. but I guess more and more people will run over this problem of compatibility of the present scripts with the new version of the Xilinx tools.

   Best regards...


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Ralph A. Schmid, dk5ras | 23 Oct 16:01 2014



I wanted to do a quick and dirty gnuradio install with pybombs, and all
looked fine, built uhd and gnuradio and what else is included in the
default, but it seems it did not add any paths and such. Is this possible,
do I have to take additional measures to have the executables reachable in a
shell, or went something wrong?

The early pybombs seemed to me a total mess, so I did not touch it for a
very long time, now I thought it should be somehow grown up and just work :)
Guess the problem sits in front of the PC...



Ralph A. Schmid
Mondstr. 10
90762 F├╝rth
ralph <at> schmid.xxx
jean-michel.friedt | 23 Oct 12:54 2014

feedback loop for bpsk carrier recovery ?

For educational purposes, I am investigating a carrier recovery scheme for BPSK demodulation.
I have synthesized a BPSK modulated signal, assembled a hardware carrier recovery scheme which
works well (squaring the modulated signal, bandpass filtering and dividing, aka Costas loop) which
I now want to implement as SDR in GNURadio. To do so, I acquire the BPSK modulated signal, extract
the carrier by squaring the I/Q data flow and bandpass filtering, all this work fine. Before squaring
the signal, I insert a Xlating FIR filter whose NCO frequency will act as the tunable VCO in the
hardware version of the carrier tracking circuit.

Question: how can I feedback the output of the lowpass filter (ie error signal of the PLL) to the
NCO of the Xlating FIR Filter ?

(I have found, following http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_PSK_Demodulation
the Costas loop block which works very well with my real signal, but I'd like to implement it
manually -- or can't gnuradio-companion close a feedback loop ?)

Additional question: since gnuradio-companion 3.7.5 I see a grey "freq" tab in the Xlating FIR
filter block, but cannot find any associated documentation or what the use of this input is. Is
this the functionality I am looking for ?

Thank you, JM


JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 Besancon, France
Douglas Geiger | 23 Oct 03:35 2014

[coproc] WG call next week

I am scheduling the next Co-Processors WG call to take place next Wednesday, October 29, 2014 <at> 2:00pm US/Eastern time (6:00pm UTC). I'll send out a reminder next week. Currently there is no agenda, so if you plan on attending and have anything you wish to discuss, please add it to the wiki page (http://gnuradio.org/redmine/projects/gnuradio/wiki/Call20141029).


Doug Geiger
doug.geiger <at> bioradiation.net
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Richard Bell | 22 Oct 23:40 2014



I just installed PyBOMBS on Ubuntu 14.04. I'm noticing that sometimes the icon labels are readable, but a lot of them are off the screen and can't be selected, like UHD. The last icon available to install for me when this happens is osmo-tetra.

To overcome this, I close PyBOMBS and restart it. Usually after this, I am able to see all the icons, but they are squished in such a way that I can't read the labels of that are missing a thumbnail picture. I can read UHD, gnuradio, gnss-sdr, etc. because those have non-default thumbnails. All the icons with ? thumbnail pics are unreadable.

Is this a known bug and is there a workaround?

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Lev Serebryakov | 22 Oct 23:39 2014

rational_resampler vs pfb_arb_resampler filter design -- why such strange cut frequencies in both cases?

 I'm looking at filter design procedures for rational_resampler and
pfb_arb_ resampler and see contradiction between them.

 Lets assume downsample with rate 3/4 or 0.75. Lets source sample rate
to be 10000 (so, target sample rate should be 7500), but, in fact, it
is irrelevant.

 rational_resampler could be configured for this task with
interpolation=3 and decimation=4. We'll set fractional_bw to "0.4" to
match arb_resampler "80%" multiplier. design_filter() method in
rational_resample.py will create low-pass filter with:

 gain = 3
 FS = 1
 transition center = 0.4/3 = 0,1(3) of 30000 = 4000 (!!!)
 transition width = 0.1

 It doesn't look resonable, as 4000 is more than 3750 which is Nyquist
frequency for targer sampling rate.

 Lets look at arbitrary resampler (pfb.py):

rate is < 1. so it takes first branch:

  gain = 32 (default number of filters)
  FS = 32 (WHY?!)
  transition center = 0.5 * 0.75 * 0.8 = 0.3 (And it should be in Hz!)
  transition width =  0.15

 As you can see, parameters are rather different. But in this case
filter should be roughly the same, because task is the same! We need
to filter out all frequencies below 3750!

 And both methods raise the questions. I could not say, that one of
the methods looks good to me. Questions are:

 (1) Why rational resampler doesn't take decimation in account when
calculates bandwidth? It design filter which will correctly reject all
images in upsample, but looks like aliasing is possibly when effective
ratio is less than 1, as only interpolation is used in bandwidth
calculation and resulting filter "effectively" works at upsampled rate.

 (2) Why arbitrary resampler set Fs to number of filters and AFTER
that pass bandwidth numbers as normalized to 1, not to this Fs?! 0.3
is perfectly good (may be slighly conservative, but Ok) transition
band center, but in this case this 0.3 will be taken for FS=1, and
here FS=32 (number of filters) is used, so it will be 32 times too low

 Are these two peculiarities two bugs, really, or I don't understand

 Yes, I've read harris' book on multirating processing, and AFTER this
book I got these questions.


Black Lion AKA Lev Serebryakov
Richard Bell | 22 Oct 21:01 2014

Installing GNU Radio

Hello Everyone,

I hate asking questions like this, but I need help installing GNU Radio. The objective is to have GNU Radio and UHD installed on Ubuntu 14.04 so I can use it with my USRP N210. The problem I have is this:

1) I don't like using the ettus easy install for 'UHD+GNU Radio' because their GNU Radio is usually several versions behind the most up to date version. I want control of what version I use.

2) I can't use apt-get install gnuradio because I need to install UHD first and apt-get install also installs a very old version of gnuradio.

What's left for me? Do I have to compile source code and go that route? I'm far from being a professional programmer, so I do not trust myself getting that done correctly. I remember reading something about a PyBombs install process related to this I think. Is that an option?

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