FYI. I found the slides about the USB interesting (even if they do not use USRP).
Jose On Mon, Feb 17, 2014 at 12:01 PM, <[email protected]> wrote: > Send Discuss-gnuradio mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Discuss-gnuradio digest..." > > > Today's Topics: > > 1. Trouble with SSB demod of real signal (Louis Brown) > 2. Re: Trouble with SSB demod of real signal (Tom McDermott) > 3. forecast (Miklos Maroti) > 4. Re: Trouble with SSB demod of real signal (Louis Brown) > 5. Re: Trouble with SSB demod of real signal (Louis Brown) > 6. Segfault in analog.quadrature_demod_cf (Matt Mills) > 7. Re: forecast (Marcus M?ller) > 8. Re: WSR14 and Hackfest (Martin Braun) > 9. ADS-B UAT decoder and hardware (David) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 16 Feb 2014 11:10:10 -0600 > From: Louis Brown <[email protected]> > To: GNURadio List Discussion <[email protected]> > Subject: [Discuss-gnuradio] Trouble with SSB demod of real signal > Message-ID: <[email protected]> > Content-Type: text/plain; CHARSET=US-ASCII > > > Hi, > > I'm exploring the LF spectrum (< 500 kHz) using a USRP N210+LFRX+active > loop antenna, and GR 3.7. I'm pulling my hair out trying to down convert > the USB as I can't get the LSB rejected. My GRC flow graph is here: > > https://dl.dropboxusercontent.com/u/49570443/test.grc.png > > It is based on figure 5 of below; quadrature, direct down conversion with > Hilbert transform. > > http://www.arrl.org/files/file/Technology/tis/info/pdf/98qex003.pdf > > > I'm taking the real output (i.e. the DAC hooked to the LFRX channel 1) of > the N210 at 25 Msps with 0 Hz DDS, then low-pass filtering at 550 kHz and > decimating to 1.25 Msps. This seems to provide better rejection of the AM > band than using the DDS tuning internal to the N210. > I then use the translating FIR filter to tune a 2 kHz passband, decimated > to 5 ksps. > > Problem comes when I try to do the LSB rejection with the Hilbert. I > think I'm using it correctly; I have tried swapping the Re and Im outputs > of the Hilbert with no luck. Maybe there is something conceptually I am > missing since I am starting with a real signal. I have done SSB demod with > complex USRP signal with no problems. > > Any ideas of what I am doing wrong? This should be basic stuff but I'm > not getting something. > > Thanks, > Lou > > > > ------------------------------ > > Message: 2 > Date: Sun, 16 Feb 2014 09:19:17 -0800 (PST) > From: Tom McDermott <[email protected]> > To: Louis Brown <[email protected]>, GNURadio List Discussion > <[email protected]> > Subject: Re: [Discuss-gnuradio] Trouble with SSB demod of real signal > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Lou - the diagram you sent isn't going to perform a single-signal > conversion. > Taking just the real part of the received signal (and throwing away the > imaginary part) > gets rid of information that distinguishes negative frequency components > from > positive frequency components. After that point there is no possibility to > separate out > the LSB components from the USB components. > ? > You will need a bit more complicated design, I've used the following > configuration for > implementing a phasing type receiver. There are other ways as well, the > Weaver method, > and a filter method (using complex taps to a filter). > ? > > http://www.tapr.org/~n5eg/index_files/DCC_2013_Gnuradio_Presentation%20-%20Rev%205.pdf > ? > Look at about slide 14. > ? > -- Tom, N5EG > ? > > > ________________________________ > From: Louis Brown <[email protected]> > To: GNURadio List Discussion <[email protected]> > Sent: Sunday, February 16, 2014 9:10 AM > Subject: [Discuss-gnuradio] Trouble with SSB demod of real signal > > > > Hi, > > I'm exploring the LF spectrum (< 500 kHz) using a USRP N210+LFRX+active > loop antenna, and GR 3.7.? I'm pulling my hair out trying to down convert > the USB as I can't get the LSB rejected.? My GRC flow graph is here: > > https://dl.dropboxusercontent.com/u/49570443/test.grc.png > > It is based on figure 5 of below; quadrature, direct down conversion with > Hilbert transform. > > http://www.arrl.org/files/file/Technology/tis/info/pdf/98qex003.pdf > > > I'm taking the real output (i.e. the DAC hooked to the LFRX channel 1) of > the N210 at 25 Msps with 0 Hz DDS, then low-pass filtering at 550 kHz and > decimating to 1.25 Msps. This seems to provide better rejection of the AM > band than using the DDS tuning internal to the N210. > I then use the translating FIR filter to tune a 2 kHz passband, decimated > to 5 ksps. > > Problem comes when I try to do the LSB rejection with the Hilbert.? I > think I'm using it correctly; I have tried swapping the Re and Im outputs > of the Hilbert with no luck.? Maybe there is something conceptually I am > missing since I am starting with a real signal.? I have done SSB demod with > complex USRP signal with no problems. > > Any ideas of what I am doing wrong?? This should be basic stuff but I'm > not getting something. > > Thanks, > Lou > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.gnu.org/archive/html/discuss-gnuradio/attachments/20140216/955484b3/attachment.html > > > > ------------------------------ > > Message: 3 > Date: Sun, 16 Feb 2014 19:12:48 +0100 > From: Miklos Maroti <[email protected]> > To: "[email protected]" <[email protected]> > Subject: [Discuss-gnuradio] forecast > Message-ID: > <CAEUdg= > [email protected]> > Content-Type: text/plain; charset=UTF-8 > > Hi Guys, > > If a block keeps some internal state, can the forecast method return > different values for the same number of noutput_items depending on its > internal state? Will the forecast method be called before the flow > graph is started? > > Miklos > > > > ------------------------------ > > Message: 4 > Date: Sun, 16 Feb 2014 13:13:21 -0600 > From: Louis Brown <[email protected]> > To: Tom McDermott <[email protected]> > Cc: GNURadio List Discussion <[email protected]> > Subject: Re: [Discuss-gnuradio] Trouble with SSB demod of real signal > Message-ID: <[email protected]> > Content-Type: text/plain; CHARSET=US-ASCII > > Tom, > > Thanks for that link. The LFRX board has two separate inputs. I'm only > using the one hooked to the I ADC, so the Q ADC is just noise, thus I > discard the imaginary output of the UHD source. The UHD source center > frequency is set to 0 Hz, so I'm direct sampling with no downconversion in > the FPGA. I'm moving what's done in the FPGA into GNU Radio to get better > rejection, thus I'm really not discarding the imaginary part since there > isn't one until after the translating FIR. > > I could drive both the I and Q ADC by splitting my received signal, but > then I have to deal with the imbalance between LFRX channels. > > Thanks, > > Lou, KD4HSO > > On Feb 16, 2014, at 11:19 AM, Tom McDermott <[email protected]> > wrote: > > > Hi Lou - the diagram you sent isn't going to perform a single-signal > conversion. > > Taking just the real part of the received signal (and throwing away the > imaginary part) > > gets rid of information that distinguishes negative frequency components > from > > positive frequency components. After that point there is no possibility > to separate out > > the LSB components from the USB components. > > > > You will need a bit more complicated design, I've used the following > configuration for > > implementing a phasing type receiver. There are other ways as well, the > Weaver method, > > and a filter method (using complex taps to a filter). > > > > > http://www.tapr.org/~n5eg/index_files/DCC_2013_Gnuradio_Presentation%20-%20Rev%205.pdf > > > > Look at about slide 14. > > > > -- Tom, N5EG > > > > > > From: Louis Brown <[email protected]> > > To: GNURadio List Discussion <[email protected]> > > Sent: Sunday, February 16, 2014 9:10 AM > > Subject: [Discuss-gnuradio] Trouble with SSB demod of real signal > > > > > > Hi, > > > > I'm exploring the LF spectrum (< 500 kHz) using a USRP N210+LFRX+active > loop antenna, and GR 3.7. I'm pulling my hair out trying to down convert > the USB as I can't get the LSB rejected. My GRC flow graph is here: > > > > https://dl.dropboxusercontent.com/u/49570443/test.grc.png > > > > It is based on figure 5 of below; quadrature, direct down conversion > with Hilbert transform. > > > > http://www.arrl.org/files/file/Technology/tis/info/pdf/98qex003.pdf > > > > > > I'm taking the real output (i.e. the DAC hooked to the LFRX channel 1) > of the N210 at 25 Msps with 0 Hz DDS, then low-pass filtering at 550 kHz > and decimating to 1.25 Msps. This seems to provide better rejection of the > AM band than using the DDS tuning internal to the N210. > > I then use the translating FIR filter to tune a 2 kHz passband, > decimated to 5 ksps. > > > > Problem comes when I try to do the LSB rejection with the Hilbert. I > think I'm using it correctly; I have tried swapping the Re and Im outputs > of the Hilbert with no luck. Maybe there is something conceptually I am > missing since I am starting with a real signal. I have done SSB demod with > complex USRP signal with no problems. > > > > Any ideas of what I am doing wrong? This should be basic stuff but I'm > not getting something. > > > > Thanks, > > Lou > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > [email protected] > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > ------------------------------ > > Message: 5 > Date: Sun, 16 Feb 2014 13:37:05 -0600 > From: Louis Brown <[email protected]> > To: Tom McDermott <[email protected]> > Cc: GNURadio List Discussion <[email protected]> > Subject: Re: [Discuss-gnuradio] Trouble with SSB demod of real signal > Message-ID: <[email protected]> > Content-Type: text/plain; CHARSET=US-ASCII > > Tom, > > OK I got it fixed after looking at your link. See diagram below: > > https://dl.dropboxusercontent.com/u/49570443/test.grc_fixed.png > > I was using the Delay block to give me a 65 sample delay to account for > the delay in the Hilbert. This will not work as I assume there is more > delay in the Hilbert than just the 65 taps. The real output of the Hilbert > is a properly delayed version of the input, so I replaced the delay with > that. It now works well What's shown in the diagram is LSB though, not > USB. > > Thanks, > Lou KD4HSO > > > > On Feb 16, 2014, at 11:19 AM, Tom McDermott <[email protected]> > wrote: > > > Hi Lou - the diagram you sent isn't going to perform a single-signal > conversion. > > Taking just the real part of the received signal (and throwing away the > imaginary part) > > gets rid of information that distinguishes negative frequency components > from > > positive frequency components. After that point there is no possibility > to separate out > > the LSB components from the USB components. > > > > You will need a bit more complicated design, I've used the following > configuration for > > implementing a phasing type receiver. There are other ways as well, the > Weaver method, > > and a filter method (using complex taps to a filter). > > > > > http://www.tapr.org/~n5eg/index_files/DCC_2013_Gnuradio_Presentation%20-%20Rev%205.pdf > > > > Look at about slide 14. > > > > -- Tom, N5EG > > > > > > > > > > > > > > > ------------------------------ > > Message: 6 > Date: Sun, 16 Feb 2014 13:52:19 -0700 > From: Matt Mills <[email protected]> > To: "[email protected]" <[email protected]> > Subject: [Discuss-gnuradio] Segfault in analog.quadrature_demod_cf > Message-ID: > <CAHH1NCcuLNgDeAt5Xexkeiq62x4jQT6WsYqP= > [email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Application that reproduces segfault: > > http://pastebin.com/Fw0y7qM9 > > debug backtrace: http://pastebin.com/FjnHu6Cs > > patch that fixes it for me, although I'm sure theres a better place to fix > it: http://pastebin.com/4gSW57Wt > > Thanks, > Matt. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.gnu.org/archive/html/discuss-gnuradio/attachments/20140216/1591c4dc/attachment.html > > > > ------------------------------ > > Message: 7 > Date: Sun, 16 Feb 2014 23:23:49 +0100 > From: Marcus M?ller <[email protected]> > To: [email protected] > Subject: Re: [Discuss-gnuradio] forecast > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi Miklos, > > yes, a forecast might be different for different situations. > > Greetings, > Marcus > > On 02/16/2014 07:12 PM, Miklos Maroti wrote: > > Hi Guys, > > > > If a block keeps some internal state, can the forecast method return > > different values for the same number of noutput_items depending on its > > internal state? Will the forecast method be called before the flow > > graph is started? > > > > Miklos > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > [email protected] > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > ------------------------------ > > Message: 8 > Date: Sun, 16 Feb 2014 23:25:14 +0100 > From: Martin Braun <[email protected]> > To: [email protected] > Subject: Re: [Discuss-gnuradio] WSR14 and Hackfest > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1 > > Sebastian, thanks for organizing this! > > On Tuesday, March 11th, there will also be the (by now traditional) > meeting of GR enthusiasts in Vogelbr?u [1]. I'll book a table for 19:00. > > MB > > [1] Address: Kapellenstra?e 50, http://www.vogelbraeu.de/ > > On 02/16/2014 03:58 PM, Sebastian Koslowski wrote: > > After the workshop we'll hold a 3-day hackfest here at the CEL- 2 > > 1/2 days to be exact, that is March 13-15. Over the last years hackfests > > have become a regular event for GR developers to get together and work > > on new features, bug fixes, and discuss where to go next. As far as I > > know this will be the first hackfest in Europe and so we would like to > > invite everyone interested to stay a few days longer in Karlsruhe and do > > some GR coding. > > > > > > > > > > ------------------------------ > > Message: 9 > Date: Sun, 16 Feb 2014 18:41:00 -0600 > From: David <[email protected]> > To: <[email protected]> > Subject: [Discuss-gnuradio] ADS-B UAT decoder and hardware > Message-ID: <[email protected]> > Content-Type: text/plain; charset=UTF-8; format=flowed > > Hi list, > > I recently posted the source code and hardware design files for a ADS-B > UAT/FIS-B receiver and decoder to Google code. There's also a python > script that contains the algorithms to decode the FIS-B weather radar > data. Perhaps they might be useful to someone working on ADS-B with > GnuRadio. > > https://code.google.com/p/lone-star-ads-b/ > > David > > > > ------------------------------ > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > End of Discuss-gnuradio Digest, Vol 135, Issue 21 > ************************************************* >
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