sysctl should really be part of any linux distro. Note that you'll have to run it as root (ie. sudo sysctl...), which should set paths accordingly.
Best regards, Marcus On 30.11.2015 13:17, Ihab Zine wrote: > HiFrederico,Marcus and /Ron, > > / > /I have good news and bad news. /// > > Frederico /I used the flow graph (obtaining parameters) //you told me > to use but i didn't get the triangle or spike, i have attached a > screen shot please see (///obtaining_parameters.gr > <http://obtaining_parameters.gr>c, Screenshot from ObtainingParameter& > Screenshot_obtaining_parameters_Terminal)/. / > > Marcus I have tried the command"sysctl -w kernel.shmmax" to increase > the available shared memory but i got (bash: sysctl: command not found). > > The good news is that i'm finally able to get the DVBT signal > synchronized and it was working earlier and i got some video and audio > working from the source, please see ( Screenshot_receiving & > Screenshot_after_ISDBT_ofdm_sym_acuistion) attached blow. i think the > problem was because of samples dropped, after i used *stream to > vector & vector to stream* at the start of the flow graph i start > seeing something working then i was adjusting *SNR* and then it was > working. Now im not able to get a video don't know why at lease i'm > getting the constellation which is good. I'll keep going and trying > to get the video and audio working again. I'll let you know guys when > i have something new. > > Big Thanks :) > > Ihab > > > On 27 November 2015 at 18:20, Ihab Zine <ihab.zin...@gmail.com > <mailto:ihab.zin...@gmail.com>> wrote: > > > > ---------- Forwarded message ---------- > From: *Federico Larroca* <flarr...@gmail.com > <mailto:flarr...@gmail.com>> > Date: Friday, November 27, 2015 > Subject: DVBT project receiver probelm > To: Ihab Zine <ihab.zin...@gmail.com <mailto:ihab.zin...@gmail.com>> > > > Hi Ihab, > You only answered to me, maybe you should forward your mail to the > list. > Regarding the grc, I would also remove the channel model (used for > simulations), as in my experience it consumes much CPU. > best > Federico > > 2015-11-27 7:22 GMT-03:00 Ihab Zine <ihab.zin...@gmail.com>: > > > ------------------------------------------------------------------------ > Hi Frederico,Marcus and /Ron > > / > /I just got access to the system, ill try to follow what you > have told me guys and ill let you know how it goes. > /// > Thanks > > // > //Ihab/ > / > > On 26 November 2015 at 17:22, Federico Larroca > <flarr...@gmail.com> wrote: > > Hi Ihab, > Those "restart aquisition" are generated by the > ofdm_sym_acquisition block when it does not find a peak on > the correlation function he uses to detect the beginning > of the OFDM symbol. You should verify there is indeed a > DVB signal precisely at 570 MHz. To do this you may use > our "Sym Align OFDM" block (not a very nice name) > available with gr-isdbt > (https://github.com/git-artes/gr-isdbt) and check that you > see a "triangle" (please refer to the readme, the > examples, and even the issues on our git). The symbol > alignment is totally equivalent between DVB-T and ISDB-T. > Moreover, I see several "O"s, meaning that somewhere > samples are being dropped. That does not help either. If > you do not have a very fast machine, you may use at the > beginning of the flowgraph a "Stream to Vector" followed > by a "Vector to Stream" with a very big "Num Items" (some > millions). > best > Federico > > 2015-11-26 12:59 GMT-03:00 Ihab Zine <ihab.zin...@gmail.com>: > > Hi, > > I’m trying to receive a live signal from an antenna on > the roof through a cable connected to my SDR (hackrf > one ).The bandwidth of the DVB-T in ireland is 8 Mhz , > and the parametetrs Here in ireland as following: > > Bandwidth: 8 MHz > Stream code rate (hi prio): FEC 2/3 > Stream code rate (lo prio): FEC 2/3 > Modulation: QAM 64 > Transmission mode: 8k mode > Guard interval: 1/32 > Hierarchy: none > > net_data_rate = 24.128 Mbits/s > > I used dvbt_rx_demo_8k_QAM64_rate78.grc flow graph > with the following changes : > > * > > frequency of hackrf one = 570 Mhz, sampling rate = > ((8*8e6)/7). > > * > > Cyclic Prefix to (8192/32, is this right?) > > * > > Code Rate HP : 2/3 > > * > > Code Rate LP : 2/3 > > * > > Guard Interval : 1/32 > > The problem i have is that no output data coming out > after the demod_reference_signals BLOCK(no > cancellation map), and got the following: > > restart aquisition > > OOrestart aquisition > > d_freq_offset: -5 > > Od_freq_offset: -5 > > d_freq_offset: -5 > > d_freq_offset: -5 > > d_freq_offset: -5 > > d_freq_offset: -5 > > d_freq_offset: -5 > > d_freq_offset: -5 > > restart aquisition > > OOd_freq_offset: -5 > > d_freq_offset: -5 > > > > so I had to add a signal source to shift the signal. > After shfting the signal i got the following : > > restart aquisition > > restart aquisition > > restart aquisition > > restart aquisition > > Orestart aquisition > > > > I have read a lot about DVB , mapping ,ofdm and > others, i have spent weeks on this but still the same > problem, if it is synchronization problem what i > should do? > > So please i need a some help with this problem . > > > > Thanks > > Ihab > > > > _______________________________________________ > 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
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