Re: [Discuss-gnuradio] How to implement 64QAM?
Any response? alanluo wrote: > > Hi, everyone: > > recently I have a project which need to use higher modulation scheme, such > as 16QAM or 64 QAM. I noticed that in python/gnuradio/blksimpl, there is > no demodualtion part for higher modulation schemes. Does that mean we need > to finish it by ourself? > And i also noticed that from the maillist attached as below, Tom seems > working on the modualtion models. Did he finish this work, and post at > some place i just did not find ? > > I really appreciate any help from you guys. Since I am very new to the > python language and dont have confidence to programme the model in such > short time. > > > RE: constellation mapping > > by trondeau Mar 06, 2007; 05:44am :: Rate this Message:- Use ratings > to moderate (?) > > Reply | Reply to Author | Print | View Threaded | Show Only this Message >> -Original Message- >> From: discuss-gnuradio-bounces+trondeau=vt@... [mailto:discuss- >> >> On Sun, Mar 04, 2007 at 06:20:07PM -0500, nj...@... wrote: >> >> > I want to do constellation mapping in pyhton. I have code that does >> > a gr.packed_to_unpacked_bb and then gr.chunks_to_symbols_bc using a >> > constellation of: >> > >> > constellation=array((1+1j,1-1j,-1-1j,-1+1j),Complex) >> >> Use this: >> >> constellation=(1+1j,1-1j,-1-1j,-1+1j) >> >> > My understanding is that this is the constellation mapping for QPSK. >> > I want to do constellation mapping for BPSK and 64-QAM. I don't >> > have a lot of GNU radio experience so I'm not really sure how to do >> > this. Is all I do is change the array (all the possibilities from >> > 4+4j to -4-4j for 64-QAM and 1+0j to -1+0j for BPSK) and the code >> > will do the rest to map the data for the other modulation schemes? >> >> Have you looked at the mpsk code that's in the tree? Most of this >> stuff is already in place. I believe that Tom Rondeau is working on >> QAM too. > ... [show rest of quote] > > Yep, you can already look in python/gnuradio/blksimpl for DBPSK and DQPSK. > I'm finishing up the tests on the new stuff now and hopefully will get > those > checked in to the trunk by the end of today. > > This will include D8PSK and a number of square QAM modulations up to > M=256. > These are currently disabled until the receivers are finished, but the > code > will be there to see how I'm doing it. The modulators have been verified > using our signal analyzer. > > Tom > > > > Best wishes, > > Alan > -- View this message in context: http://old.nabble.com/How-to-implement-64QAM--tp27396489p2747.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] USRP2 MIMO setup problem
Hi all, I am trying to create a two transmitter setup with two USRP2s connected with the MIMO cable. I use the trunk version of GNURadio (Friday, Jan 29,2010) on laptops running Ubuntu 9.04. >From previous emails and looking at the code, the relevant code for two transmitter setup seems to be the test_mimo_tx file in usrp2/host/apps. I update the firmware of the master USRP2 with mimo_tx.bin as pointed out in http://gnuradio.org/redmine/wiki/gnuradio/USRP2UserFAQ. sudo ./u2_flash_tool --dev=/dev/sdb -t s/w apps/mimo_tx.bin -w and for the slave USRP2, I use sudo ./u2_flash_tool --dev=/dev/sdb -t s/w apps/mimo_tx_slave.bin -w When I invoke the transmission program at the sender laptop using sudo ./test_mimo_tx -f 2.412G -I a.dat -i 100 -r I observe the following message: usrp2::ctor reset_db failed. The USRP2 freezes after this and the host cannot find it using find_usrps. The archives of the mailing list suggest updating the firmware to solve this issue. But I want to use the MIMO firmware and not the usual txrx.bin. 1. Is there firmware for the MIMO master and slave, which does not have this problem? 2. What modifications need to be incorporated to the current MIMO files to fix this problem? If there is not a solution already, I am thinking of modifying the existing MIMO USRP2 related files. Any pointers on what are to be taken care of, will be very useful. Thanks, Sri ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
RE: [Discuss-gnuradio] Unable to tune Tx or Rx with XCVR2450 on USRP2
Hi Manav
I haven't really fixed it, but rather get a different error. To do this,
I updated to the latest copy of firmware and fpga images as Josh had
suggested.
I am yet to try the debug port and see if it is failing to lock.
Hopefully I can try this today.
Ian.
From: Manav Seth [mailto:smartyma...@gmail.com]
Sent: Friday, 29 January 2010 6:11 PM
To: Ian Holland
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] Unable to tune Tx or Rx with XCVR2450 on
USRP2
Hey Ian,
How did the problem get fixed? I mean what frequency you are setting
with the "-f" option?
Regards,
Manav
On Thu, Jan 28, 2010 at 10:17 PM, Ian Holland
wrote:
Thanks Josh
This partially fixed the problem, in the sense that samples are now
displayed on the fft window when running usrp2_fft.py, and it no longer
says "channel 0 not receiving". However, it still fails to set the
frequency of the receiver. Also, when I run usrp_siggen.py, I still get
the same problem that the Tx frequency can't be set. In verbose mode,
the output of usrp_siggen.py is as below. Any ideas on what else could
be wrong?
Regards
Ian.
USRP interpolation rate: 16
USRP IF bandwidth: 6.25MHz
Set TX gain to: 15.0
Using auto-calculated mid-point frequency
Failed to set freq.
(...etc...)
>Your firmware and fpga images on the sd card are probably out of sync.
>You can find images here: http://gnuradio.org/releases/usrp2-bin/trunk/
>and here are instructions on how to burn:
>http://gnuradio.org/redmine/wiki/gnuradio/USRP2UserFAQ
>-Josh
On 01/28/2010 06:14 PM, Ian Holland wrote:
> Hi Matt
>
> I have tried usrp2_fft.py -f 2.4G and also usrp2_fft.py -f 5.7G as you
> suggest below. In both cases, the fft window opens but no trace is
> displayed, and I see the following output in the terminal:
>
> usrp2: channel 0 not receiving
> usrp2::rx_sample() failed
>
> I only recently received my USRP2s and XCVR2450s, which were shipped
at
> the end of December. Are there any known issues with the firmware on
the
> SD cards at this time, or do you have any other idea why I can't seem
to
> tune frequencies on these cards?
>
> Thanks
>
> Ian.
>
> -Original Message-
> From: Matt Ettus [mailto:m...@ettus.com]
> Sent: Friday, 29 January 2010 12:35 PM
> To: Manav Seth
> Cc: Ian Holland; discuss-gnuradio@gnu.org
> Subject: Re: [Discuss-gnuradio] Unable to tune Tx or Rx with XCVR2450
on
> USRP2
>
>
>
> The -f argument to usrp2_fft.py is the frequency. By putting "-f
1000"
> you are telling the system to try to tune the xcvr2450 to 1 kHz. The
> specified range is 2.4-2.5 GHz and 4.9 to 5.9 GHz. 1 kHz is WAY
outside
>
> of that range. I would suggest you try something like:
>
> usrp2_fft.py -f 5.7G
>
> Matt
>
> On 01/28/2010 05:35 PM, Manav Seth wrote:
>> Actually no...its always returning false...
>> when I use usrp2_fft.py with -f 1000 then output does come but still
> it
>> is unable to set the initial frequency though it did receive.
>>
>> I am still trying to figure out the problem...
>>
>> On Thu, Jan 28, 2010 at 3:43 PM, Ian Holland
>> mailto:ian.holl...@rlmgroup.com.au>>
> wrote:
>>
>> On Wed, Jan 27, 2010 at 8:52 PM, Ian Holland
>>
mailto:ian.holl...@rlmgroup.com.au>>
>> wrote:
>> Hi All
>>
>> I have been trying to set the Tx and Rx frequencies when using
an
>> XCVR2450 with a USRP2, but it seems these keep failing. A
snippet
> of my
>> source code is below for setting the Tx frequency.
>> The output of this portion of code is "Failed to tune Tx", and
the
>> frequencies are all 0, with spectrum_inverted being false.
>> I have also tried to use usrp2_fft.py, and this fails saying
> nothing is
>> received on channel 0.
>> Does anyone know what the problem could be?
>>
>> Thanks
>>
>> Ian.
>>
>> /* try tuning Tx to a test frequency */
>> double Fc = 24.0;
>> usrp2::tune_result TxTuneResult;
>> bool successTx = device->set_tx_center_freq(Fc,
>> &TxTuneResult);
>> if(successTx) {
>> cout<< "Tx Tune
Successful:\n";
>> cout<< "Baseband Frequency: "<<
>> TxTuneResult.baseband_freq<< "\n";
>> cout<< "DxC Frequency: "<<
>> TxTuneResult.dxc_freq<< "\n";
>> cout<< "Residual Frequency: "<<
>> TxTuneResult.residual_freq<< "\n";
>> cout<< "Spectrum Inverted: "<<
>> (TxTuneResult.spectrum_inverted ? "true" : "false")<< "\n";
>> }
>> else {
>> cout<< "Failed to tune Tx.\n";
>> cout<< "Baseband Frequency: "<<
>> TxTuneResult.baseband_freq<< "\n";
>> cout<< "DxC Frequency: "<<
>> TxTuneResult.dxc_freq<< "\n";
>> cout<< "Residual Frequency:
[Discuss-gnuradio] How to implement 64QAM?
Hi, everyone: recently I have a project which need to use higher modulation scheme, such as 16QAM or 64 QAM. I noticed that in python/gnuradio/blksimpl, there is no demodualtion part for higher modulation schemes. Is that means we need to finish it by ourself? And i also noticed that from the maillist attached as below, Tom seems working on the modualtion models. Did he finish this work, and post at some place i just did not find ? I really appreciate any help from you guys. Since I am very new to the python language and dont have confidence to programme the model in such short time. RE: constellation mapping by trondeau Mar 06, 2007; 05:44am :: Rate this Message:- Use ratings to moderate (?) Reply | Reply to Author | Print | View Threaded | Show Only this Message > -Original Message- > From: discuss-gnuradio-bounces+trondeau=vt@... [mailto:discuss- > > On Sun, Mar 04, 2007 at 06:20:07PM -0500, nj...@... wrote: > > > I want to do constellation mapping in pyhton. I have code that does > > a gr.packed_to_unpacked_bb and then gr.chunks_to_symbols_bc using a > > constellation of: > > > > constellation=array((1+1j,1-1j,-1-1j,-1+1j),Complex) > > Use this: > > constellation=(1+1j,1-1j,-1-1j,-1+1j) > > > My understanding is that this is the constellation mapping for QPSK. > > I want to do constellation mapping for BPSK and 64-QAM. I don't > > have a lot of GNU radio experience so I'm not really sure how to do > > this. Is all I do is change the array (all the possibilities from > > 4+4j to -4-4j for 64-QAM and 1+0j to -1+0j for BPSK) and the code > > will do the rest to map the data for the other modulation schemes? > > Have you looked at the mpsk code that's in the tree? Most of this > stuff is already in place. I believe that Tom Rondeau is working on > QAM too. ... [show rest of quote] Yep, you can already look in python/gnuradio/blksimpl for DBPSK and DQPSK. I'm finishing up the tests on the new stuff now and hopefully will get those checked in to the trunk by the end of today. This will include D8PSK and a number of square QAM modulations up to M=256. These are currently disabled until the receivers are finished, but the code will be there to see how I'm doing it. The modulators have been verified using our signal analyzer. Tom Best wishes, Alan -- View this message in context: http://old.nabble.com/How-to-implement-64QAM--tp27396489p27396489.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] BER in bert- example
On Sun, Jan 31, 2010 at 06:52, Brian Padalino wrote: >> But from my tests I see that >> 1 bit error in -> 7 bit errors out >> 2 consecutive bit errors in -> 2 errors in the output >> 3 consecutive bit errors in -> 7 errors in the output >> 4 consecutive bit errors in -> 4 errors in the output >> ... >> And so forth up to 7 (Length of the lfsr) >> >> The reason I ask is that if I want to change the scrambler and/or the >> modulation, I assume that this "magic number" will change as well. > > If you want a good BER measurement, I wouldn't use the method that you > describe here. You are correct. The scrambler introduces three output errors per input error for single channel errors that are farther apart than the length of the shift register. This is the case once the shift register has already achieved self-synchronization and at low channel error rates. For the purposes of the simple BERT example, this was sufficient. (The number 3 comes from the number of taps in the scrambler polynomial.) Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] BER in bert- example
On Sun, Jan 31, 2010 at 7:36 AM, Mattias Kjellsson wrote: > Hi list, > > There is a function called 'ber' in receive_path.py in the python bert > example. > > def ber(self): > return (1.0-self._ber.density())/3.0 > > From where does the 3 originate? Some lines above, there is this comment: > # Descramble BERT sequence. A channel error will create 3 incorrect bits > self._descrambler = gr.descrambler_bb(0x8A, 0x7F, 7) # CCSDS 7-bit > descrambler > > But from my tests I see that > 1 bit error in -> 7 bit errors out > 2 consecutive bit errors in -> 2 errors in the output > 3 consecutive bit errors in -> 7 errors in the output > 4 consecutive bit errors in -> 4 errors in the output > ... > And so forth up to 7 (Length of the lfsr) > > The reason I ask is that if I want to change the scrambler and/or the > modulation, I assume that this "magic number" will change as well. If you want a good BER measurement, I wouldn't use the method that you describe here. Since, as you've noted, the errors propagate through the shift register and generate more errors than the number of errors at the input, it seems more like an error generator than an error counter. Though, on a side note, it is strange you are getting 7 bits in error when you only have 1 bit in error going in. This really should be limited to 3 as the comment suggests. The benefit to this approach is self-synchronization, but you lose out on an accurate bit error measurement. Without knowing more about the type of system you are going to be testing, I can't comment on how I'd change the measurement or evaluation of the bits produced by your modem. Sorry. Hope this was helpful - though I somewhat doubt it. Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Soft-DVB has a Brother. A Receiving Brother. And Fast...
SR-DVB demo video on youtube http://www.youtube.com/watch?v=S5nGBDCxhmk regards vincenzo ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] BER in bert- example
Hi list, There is a function called 'ber' in receive_path.py in the python bert example. def ber(self): return (1.0-self._ber.density())/3.0 From where does the 3 originate? Some lines above, there is this comment: # Descramble BERT sequence. A channel error will create 3 incorrect bits self._descrambler = gr.descrambler_bb(0x8A, 0x7F, 7) # CCSDS 7-bit descrambler But from my tests I see that 1 bit error in -> 7 bit errors out 2 consecutive bit errors in -> 2 errors in the output 3 consecutive bit errors in -> 7 errors in the output 4 consecutive bit errors in -> 4 errors in the output ... And so forth up to 7 (Length of the lfsr) The reason I ask is that if I want to change the scrambler and/or the modulation, I assume that this "magic number" will change as well. BR //Mattias ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Questions about synchronization and modulation in benchmark
Hi Adib Thanks for the reply. I check it in the net and download it. I don't know about costas loop and clock recovery in detail. may I know how they they estimate frequency offset, and recover it? as far as I know, they are using gr.quadrature_demod_cf(1) & and subtract it using gr.single_pole_iif_filter_ff(alpha) for frequency offset?is it right? Tim On Sun, Jan 31, 2010 at 4:03 PM, adib_sairi wrote: > > there is some work from Thomas Schmid which modulate and demodulate O-QPSK > which mean for IEEE802.15.4 standard.. you can search and download the code > online. good luck.. > > Adib > > > Timothy Lawrence Sitorus wrote: > > > > HI all, > > > > Please anyone help me. > > > > Is there anyone succeeded to modulate qpsk, even frequency offset occurs? > > > > > > Best Regards, > > Tim > > > > ___ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > -- > View this message in context: > http://old.nabble.com/Questions-about-synchronization-and-modulation-in-benchmark-tp27371719p27390702.html > Sent from the GnuRadio mailing list archive at Nabble.com. > > > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
