Re: [Discuss-gnuradio] Problems while using UHD based API's
Thanks Josh.. got it.. Josh Blum-3 wrote: > > > > On 09/05/2011 11:28 AM, sumitstop wrote: >> >> Yesterday I installed GnuRadio with Marcus script in some PC's.Burnt the >> SD >> card with images in the folder >> >> /usr/local/share/uhd/images >> >> and uhd_find_devices found all my 3 usrp2. >> >> But when I tried to run uhd_fft it displayed that >> "FPGA build of the device is incompatible with the host code build." >> >> Then I went to another PC where I installed GnuRadio using Marcus script >> 2 >> months back.I burnt the fpga and firmware file from that system from the >> same folder and uhd_fft worked well in that system.I was able to see the >> spectrum. >> >> Where I am wrong. :confused: > > Marcus can comment on his script... > > For each release there is a set of compatible images. Also, all of the > development happens on the master branch, so if you update your host > code to the latest master branch, you will often have to update the > images package. The host code will perform a compatibility check and > throw an exception if the compatibility does not match. > > Images and release binaries can be found here (including images that > will work with the latest master branch): > http://code.ettus.com/redmine/ettus/projects/uhd/wiki#Binary-downloads > >> ___ >> >> I would like to know if all the UHD based API's has been appended with >> "UHD"? >> i.e uhd_find_devices etc >> > > These are not APIs, they are executable files; and generally they have > this naming convention. > >> I would also like to know that are the python scripts also been >> classified >> according to UHD based and Raw ethernet Driver based.If yes then how can >> I >> know. >> > > Most often, they have the name usrp2 in them. > > -josh > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > - Sumit Kr. Research Assistant Communication Research center IIIT Hyderabad India -- View this message in context: http://old.nabble.com/Problems-while-using-UHD-based-API%27s-tp32403021p32405295.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Turbo encoding/decoding GRC blocks + examples
On 08/31/2011 05:48 PM, Achilleas Anastasopoulos wrote: > Hey all, > > I updated gr-trellis with serial/parallel turbo encoders > and decoders and corresponding GRC blocks, as well as some examples > in gnuradio-examples/grc/trellis > > I have these updates on branch "turbo" on my github site: > https://github.com/anastas/gnuradio_turbo.git > in case you can't wait until they are merged to MASTER :-) > > Looks like a bunch of generated files gr-trellis/src/lib/trellis_pccc_decoder_combined* got checked in. http://gnuradio.org/cgit/gnuradio.git/tree/gr-trellis/src/lib > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_XX.cc.t > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_XX.h.t > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_XX.i.t > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_cb.cc > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_cb.h > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_cb.i > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_ci.cc > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_ci.h > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_ci.i > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_cs.cc > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_cs.h > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_cs.i > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fb.cc > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fb.h > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fb.i > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fi.cc > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fi.h > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fi.i > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fs.cc > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fs.h > # new file: gr-trellis/src/lib/trellis_pccc_decoder_combined_fs.i -Josh ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] How to display constellation in gnuradio
I have found it, but i'd like to add FFT before sopesink2 of wxgui, there a error in it. the error info is "itemsize mismatch:gr uhd usrp source(1):0 using 8,fft_vcc_fftw(14):0 using 4096",how to have their itemsizi matched? 2011/9/5 Josh Blum : > > > On 09/04/2011 04:42 AM, guojun chang wrote: >> How to display constellation in gnuradio? I know that uhd_fft.py can >> show a window, but there is not anything what i need. I appreciate any >> help, thanks a lot in advance. >> > > The both the qtgui sink and wxgui scope sink has an XY mode to plot > complex input. > > -josh > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] OFDM Implementation
Thanks for you help sumit. i really appriciate that . i will go through this link and will let you know if i will have any further question or problem regarding the OFDM implementation. Thanks once again. Regards, Waqas. sumitstop wrote: > > refer to this.. > > http://pwnhome.wordpress.com/2011/01/29/intro-to-gnuradio-and-the-usrp-part-2-visualizing-the-waves/ > > > > waqasme wrote: >> >> Hello All, >> Does anyone know how to implement OFDM implementation by USING GNU RADIO >> COMPANION. Some one told me to use Benchmark_OFDM.py script. But i am not >> sure how this will work and how we can put this script in GNU radio >> companion to make the simulation. If any one know please guide me . i >> will really appriciate that. >> >> Regards, >> Waq. >> > > -- View this message in context: http://old.nabble.com/OFDM-Implementation-tp32380874p32404346.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Problems while using UHD based API's
Here is the error. cogwsn@cogwsn-desktop:/usr/local/bin$ uhd_fft.py linux; GNU C++ version 4.4.3; Boost_104000; UHD_003.002.003-583c762 -- Opening a USRP2/N-Series device... -- Current recv frame size: 1472 bytes -- Current send frame size: 1472 bytes Traceback (most recent call last): File "/usr/local/bin/uhd_fft.py", line 267, in main () File "/usr/local/bin/uhd_fft.py", line 263, in main app = stdgui2.stdapp(app_top_block, "UHD FFT", nstatus=1) File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py", line 36, in __init__ wx.App.__init__ (self, redirect=False) File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7978, in __init__ self._BootstrapApp() File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7552, in _BootstrapApp return _core_.PyApp__BootstrapApp(*args, **kwargs) File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py", line 39, in OnInit frame = stdframe (self.top_block_maker, self.title, self._nstatus) File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py", line 60, in __init__ self.panel = stdpanel (self, self, top_block_maker) File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py", line 81, in __init__ self.top_block = top_block_maker (frame, self, vbox, sys.argv) File "/usr/local/bin/uhd_fft.py", line 70, in __init__ num_channels=1) File "/usr/local/lib/python2.6/dist-packages/gnuradio/uhd/__init__.py", line 74, in constructor_interceptor return old_constructor(*args, **kwargs) File "/usr/local/lib/python2.6/dist-packages/gnuradio/uhd/uhd_swig.py", line 1856, in usrp_source return _uhd_swig.usrp_source(*args, **kwargs) RuntimeError: RuntimeError: Please update the firmware and FPGA images for your device. See the application notes for USRP2/N-Series for instructions. Expected FPGA compatibility number 7, but got 6: The FPGA build is not compatible with the host code build. I re-run the script in the same PC.I went to the folder usr/local/share/uhd/image I saw a tag 003.001.002 while the latest release is 003.002.003 at http://files.ettus.com/uhd_releases/master_images/ In another PC I re-run the script and before that I deleted that UHD folder.Now the tag is missing.Cant say which version. Anyways my problem has solved after I burnt my SD card with the latest release :) Marcus D. Leech wrote: > > > On 09/05/2011 02:28 PM, sumitstop wrote: >> Yesterday I installed GnuRadio with Marcus script in some PC's.Burnt the >> SD >> card with images in the folder >> >> /usr/local/share/uhd/images >> >> and uhd_find_devices found all my 3 usrp2. >> >> But when I tried to run uhd_fft it displayed that >> "FPGA build of the device is incompatible with the host code build." >> >> Then I went to another PC where I installed GnuRadio using Marcus script >> 2 >> months back.I burnt the fpga and firmware file from that system from the >> same folder and uhd_fft worked well in that system.I was able to see the >> spectrum. >> >> Where I am wrong. :confused: >> > Please do two things: > > Re-run your failed tests, but send us the *complete* error output. > > > Re-fetch, and re-run the build-gnuradio script > > > > > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org > > > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > - Sumit Kr. Research Assistant Communication Research center IIIT Hyderabad India -- View this message in context: http://old.nabble.com/Problems-while-using-UHD-based-API%27s-tp32403021p32404004.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Problems while using UHD based API's
On 09/05/2011 02:28 PM, sumitstop wrote: Yesterday I installed GnuRadio with Marcus script in some PC's.Burnt the SD card with images in the folder /usr/local/share/uhd/images and uhd_find_devices found all my 3 usrp2. But when I tried to run uhd_fft it displayed that "FPGA build of the device is incompatible with the host code build." Then I went to another PC where I installed GnuRadio using Marcus script 2 months back.I burnt the fpga and firmware file from that system from the same folder and uhd_fft worked well in that system.I was able to see the spectrum. Where I am wrong. :confused: Please do two things: Re-run your failed tests, but send us the *complete* error output. Re-fetch, and re-run the build-gnuradio script -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Problems while using UHD based API's
On 09/05/2011 11:28 AM, sumitstop wrote: > > Yesterday I installed GnuRadio with Marcus script in some PC's.Burnt the SD > card with images in the folder > > /usr/local/share/uhd/images > > and uhd_find_devices found all my 3 usrp2. > > But when I tried to run uhd_fft it displayed that > "FPGA build of the device is incompatible with the host code build." > > Then I went to another PC where I installed GnuRadio using Marcus script 2 > months back.I burnt the fpga and firmware file from that system from the > same folder and uhd_fft worked well in that system.I was able to see the > spectrum. > > Where I am wrong. :confused: Marcus can comment on his script... For each release there is a set of compatible images. Also, all of the development happens on the master branch, so if you update your host code to the latest master branch, you will often have to update the images package. The host code will perform a compatibility check and throw an exception if the compatibility does not match. Images and release binaries can be found here (including images that will work with the latest master branch): http://code.ettus.com/redmine/ettus/projects/uhd/wiki#Binary-downloads > ___ > > I would like to know if all the UHD based API's has been appended with > "UHD"? > i.e uhd_find_devices etc > These are not APIs, they are executable files; and generally they have this naming convention. > I would also like to know that are the python scripts also been classified > according to UHD based and Raw ethernet Driver based.If yes then how can I > know. > Most often, they have the name usrp2 in them. -josh ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] OFDM Implementation
refer to this.. http://pwnhome.wordpress.com/2011/01/29/intro-to-gnuradio-and-the-usrp-part-2-visualizing-the-waves/ waqasme wrote: > > Hello All, > Does anyone know how to implement OFDM implementation by USING GNU RADIO > COMPANION. Some one told me to use Benchmark_OFDM.py script. But i am not > sure how this will work and how we can put this script in GNU radio > companion to make the simulation. If any one know please guide me . i will > really appriciate that. > > Regards, > Waq. > - Sumit Kr. Research Assistant Communication Research center IIIT Hyderabad India -- View this message in context: http://old.nabble.com/OFDM-Implementation-tp32380874p32403125.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Problems while using UHD based API's
Yesterday I installed GnuRadio with Marcus script in some PC's.Burnt the SD card with images in the folder /usr/local/share/uhd/images and uhd_find_devices found all my 3 usrp2. But when I tried to run uhd_fft it displayed that "FPGA build of the device is incompatible with the host code build." Then I went to another PC where I installed GnuRadio using Marcus script 2 months back.I burnt the fpga and firmware file from that system from the same folder and uhd_fft worked well in that system.I was able to see the spectrum. Where I am wrong. :confused: ___ I would like to know if all the UHD based API's has been appended with "UHD"? i.e uhd_find_devices etc I would also like to know that are the python scripts also been classified according to UHD based and Raw ethernet Driver based.If yes then how can I know. There is plethora of learning in GnuRadio and USRP and I am enjoying it :) - Sumit Kr. Research Assistant Communication Research center IIIT Hyderabad India -- View this message in context: http://old.nabble.com/Problems-while-using-UHD-based-API%27s-tp32403021p32403021.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmit filtering
On 09/05/2011 01:10 PM, Marcus D. Leech wrote: On 05/09/11 12:55 PM, John Ackermann N8UR wrote: Hi Marcus -- I am selecting complex taps from the drop down, but still get an error at runtime if either cutoff frequency is 0 or smaller. Thanks, John I just tried it, and it works just fine. I select: Complex->Complex (complex taps) from the menu, with a complex I/O, and I'm able to specify negative frequency components. What is the error you're getting at runtime? Using a band reject filter with low frequency set to -1 and high frequency set to 1, dropdown of complex(decimating), I get this: Traceback (most recent call last): File "/home/jra/gnuradio/fm_rx.py", line 166, in tb = fm_rx() File "/home/jra/gnuradio/fm_rx.py", line 115, in __init__ 1, 20, -1, 1, 1000, firdes.WIN_HAMMING, 6.76)) File "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/gnuradio_core_general.py", line 3437, in band_reject return _gnuradio_core_general.firdes_band_reject(*args, **kwargs) IndexError: gr_firdes check failed: 0 < fa <= sampling_freq / 2 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmit filtering
On 05/09/11 12:55 PM, John Ackermann N8UR wrote: > Hi Marcus -- > > I am selecting complex taps from the drop down, but still get an error at > runtime if either cutoff frequency is 0 or smaller. > > Thanks, > > John > > > I just tried it, and it works just fine. I select: Complex->Complex (complex taps) from the menu, with a complex I/O, and I'm able to specify negative frequency components. What is the error you're getting at runtime? -- Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Problems with the current GIT source for Gnu Radio
On Sun, Sep 4, 2011 at 12:37 AM, Marcus D. Leech wrote: > On 04/09/11 12:21 AM, Josh Blum wrote: > > > >> That appears to be exactly the cause! And would explain why > >> rolling-back my local gnuradio clone to before 2011-08-22 had no > >> effect, since it was caused by pkg-config (via the > >> autoconf/automake/configure chain) putting all that extra (and wrong) > goop > >> into UHD_LIBS. > >> > >> > > 1) It looks like autotools is sucking Libs.private and Requires.private > > to determine the flags. Is that the correct behavior? > > > > I suppose that its up the build system, but on your platform (most linux > > i assume), explicit linking of nested dependencies isnt needed. So that > > why I think the pc files *.private stuff should be left out in this case. > > > > http://people.freedesktop.org/~dbn/pkg-config-guide.html#concepts > > > It looks like the autotools emit the --static option on pkg-config > --libs, which > will always include the Libs.private stuff from the .pc file, it seems. Glad that's been cleared up for now. With the conference coming up and everything else I need to do, this is going to have to go onto the stack for now. Might wait until we see about the cmake switch-over, too, before revisting these issues and working them out. Tom ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmit filtering
On Mon, Sep 5, 2011 at 12:55 PM, John Ackermann N8UR wrote: > Hi Marcus -- > > I am selecting complex taps from the drop down, but still get an error at > runtime if either cutoff frequency is 0 or smaller. > > Thanks, > > John > John, That sounds like a bug in the GRC block, then. I just tried this as a complex BPF and it works fine: gr.firdes.complex_band_pass(1, 1, -0.1, 0.2, 0.1) However, as was already mentioned, if you are trying to create a bandpass filter from -40 to +40 kHz, that's just a low pass filter with a bandwidth of 40 kHz: gr.firdes.low_pass(1, 100e3, 40e3, 2e3) Will give you a filter for this purpose. Substitute your own sampling rate and transition width, of course. Tom > On Sep 5, 2011, at 11:46 AM, "Marcus D. Leech" wrote: > > > On 05/09/11 10:19 AM, John Ackermann N8UR wrote: > >> I'm generating two NBFM signals, offsetting them plus and minus 25 kHz > >> with FreqXlatingFilters, and combining the output in an adder which > >> then drives a USRP sink. It seems sensible to put a bandpass filter > >> on the result. > >> > >> I have a basic conceptual confusion. I would think that you'd specify > >> a bandpass filter around zero with a low cutoff of, say, -40e3 and a > >> high cutoff of +40e3. However, this doesn't work -- the bandpass > >> filter seems to require a number >0 for the lowpass frequency. > > Make sure that you specify complex-taps. I assume you're using GRC. By > > default, it uses the version of > > the bandpass filter with real taps. But if you specify complex taps, > > you can use negative frequencies. > > > > > > -- > > Principal Investigator > > Shirleys Bay Radio Astronomy Consortium > > http://www.sbrac.org > > > > > > > > ___ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] PFB Filterbank & arbitrary resampler
On Sun, Sep 4, 2011 at 11:33 AM, Ryan Pape wrote: > > We are successfully using the PFB filterbank to channelize 1-6mhz into a > variety of channel widths (25K, 50K etc). > > In one application, we have 25K channels which are then resampled using PFB > resampler to 19.2K fed into gmsk_demod @ 9600bps with 2sps. > > In this case, we may have 20-40 ports "active" (not null sink) with pfb > resamplers connected to each. > > Is there way to perform this resampling in the filterbank to avoid the > need for many separate resampler blocks in an effort to improve performance? > > We are pushing the limits of hardware already, so any efficiencies are > helpful. We will consider a hierarchical filterbank structure if necessary, > but our first goal is to do it with one filterbank, if possible. > Ryan, What you are talking about is possible, but not with the current implementation of the GNU Radio channelizer. fred harris has recently published a few papers on doing arbitrary channel / arbitrary bandwidth channelizers that should meet your needs, but it would have to be programmed up. Now, that having been said, there is a way to handle this. If you have a 9600 bps signal in a 25 ksps channel, you can switch to using the gr_pfb_clock_resampler_fff block, which allows you to specify a real number for the number of samples per symbol (2.6042 in this case) instead of integers. That should do the trick. Tom ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmit filtering
Hi Marcus -- I am selecting complex taps from the drop down, but still get an error at runtime if either cutoff frequency is 0 or smaller. Thanks, John On Sep 5, 2011, at 11:46 AM, "Marcus D. Leech" wrote: > On 05/09/11 10:19 AM, John Ackermann N8UR wrote: >> I'm generating two NBFM signals, offsetting them plus and minus 25 kHz >> with FreqXlatingFilters, and combining the output in an adder which >> then drives a USRP sink. It seems sensible to put a bandpass filter >> on the result. >> >> I have a basic conceptual confusion. I would think that you'd specify >> a bandpass filter around zero with a low cutoff of, say, -40e3 and a >> high cutoff of +40e3. However, this doesn't work -- the bandpass >> filter seems to require a number >0 for the lowpass frequency. > Make sure that you specify complex-taps. I assume you're using GRC. By > default, it uses the version of > the bandpass filter with real taps. But if you specify complex taps, > you can use negative frequencies. > > > -- > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org > > > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmit filtering
On 05/09/11 10:19 AM, John Ackermann N8UR wrote: > I'm generating two NBFM signals, offsetting them plus and minus 25 kHz > with FreqXlatingFilters, and combining the output in an adder which > then drives a USRP sink. It seems sensible to put a bandpass filter > on the result. > > I have a basic conceptual confusion. I would think that you'd specify > a bandpass filter around zero with a low cutoff of, say, -40e3 and a > high cutoff of +40e3. However, this doesn't work -- the bandpass > filter seems to require a number >0 for the lowpass frequency. Make sure that you specify complex-taps. I assume you're using GRC. By default, it uses the version of the bandpass filter with real taps. But if you specify complex taps, you can use negative frequencies. -- Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmit filtering
On Mon, Sep 05, 2011 at 10:19:54AM -0400, John Ackermann N8UR wrote: > > I would think that you'd specify a bandpass filter around zero with a > low cutoff of, say, -40e3 and a high cutoff of +40e3. However, this > doesn't work -- the bandpass filter seems to require a number >0 for > the lowpass frequency. That would be a low-pass filter with a cutoff at 40e3. With complex-valued signals, a low-pass filter is essentially a band-pass filter centered around 0 Hz. > there is a signal component on the output directly at the USRP center > frequency. It's at most about 30dB below the desired signals. I > assume this is the equivalent of LO leakage. Is there any way to > filter this out or at least reduce its amplitude? > > As I'm writing this, I wonder if the solution to both problems is to > put both my signals on one side of the USRP center frequency, say +25 > and +75 kHz. Yes, you could use an external analog band-pass filter if that center spur is a problem for you. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Transmit filtering
I'm generating two NBFM signals, offsetting them plus and minus 25 kHz with FreqXlatingFilters, and combining the output in an adder which then drives a USRP sink. It seems sensible to put a bandpass filter on the result. I have a basic conceptual confusion. I would think that you'd specify a bandpass filter around zero with a low cutoff of, say, -40e3 and a high cutoff of +40e3. However, this doesn't work -- the bandpass filter seems to require a number >0 for the lowpass frequency. So, in this situation, where I want to filter a spectrum that is centered around zero, how do I specify the filter lowpass and highpass frequencies? A second question -- there is a signal component on the output directly at the USRP center frequency. It's at most about 30dB below the desired signals. I assume this is the equivalent of LO leakage. Is there any way to filter this out or at least reduce its amplitude? As I'm writing this, I wonder if the solution to both problems is to put both my signals on one side of the USRP center frequency, say +25 and +75 kHz. That would allow a sensible bandpass filter that would remove the zero-frequency component. But the downside of that seems to be throwing away half the available bandwidth. Thanks, John ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Transmitting additional data from N210 to the PC
On 09/04/2011 11:18 PM, Eral Tuerkyilmaz wrote: > Hi, > > I want to change my USRP N210 - FPGA config to calculate a correlation > sum and transmit this sum synchronously with the I/Q sample pairs to the > PC (e.g to get this samples from an extra channel on the UHD block). > What would be the easiest way to transmit these additional data to the > samples and where are changes necessary (firmware, fpga-config)? > You may want to replace the second DSP in the top level verilog with your own module. On the host side, just configure the uhd source block for two channels. -josh ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio