Luke, I researched this for a bit (OK, maybe it was more like staring blankly)... unfortunately on a windows machine w/out git. Nothing stands out at the momentt. I'll give it another try tomorrow! =)
Also, I've never used the PLL blocks for freq demod before. Can you set something up with a graphical sink and send some snapshots showing what the output of that looks like? Also also, is the Band-Edge FLL ideal for GMSK? My possibly, incorrect understanding of that block is that it was more ideal for PAM with common RRC. -John On Thu, Oct 16, 2014 at 7:19 AM, Luke Berndt <[email protected]> wrote: > I just tried doing a complete PyBombs reinstall and that didn't seem the > help. I checked and simple GRC files run fine. I can also see the signal > where I expect it to be in GQRX, so I think my tuning parameters are > correct. > > Are there some other things I should try? > > Sent from my iPhone > > On Oct 13, 2014, at 1:38 PM, Luke Berndt <[email protected]> wrote: > > I have a GnuRadio C++ program that decodes and records a SmartNet Trunked > radio system. It is running great under GnuRadio 3.6.5.1, but it doesn’t > seem to be working under 3.7.6. > > 3.6 is installed in /usr/local and 3.7.6 was installed in my home > directory using PyBombs. My updated program compiles against 3.7 with no > problem and runs. It will pick up a few of the trunking commands, so it is > working, but the ratios is about 1 to 100 compared to 3.6. I also tried > running it in a Ubuntu VM with 3.7 installed at /usr/local and had the same > results. > > I corrected for the change with XlatingFirFilter in 3.7, so it is the > opposite offset of 3.6. It looks like it could be a tuning error though, > the flow graph seems to be failing mostly at the CRC check. Did anything > else change with Blocks in 3.7? I looked at gr-osmosdr but I didn’t notice > huge discrepancies between the 3.6 and 3.7 branches. > > Are there some obvious things I could be missing? I feel like this is > something small and stupid that I missing. > > The diff between the two versions is here, smartness.cc is the main file > that decodes the control channel. As you can see, there is not that much > different: > > > https://github.com/robotastic/smartnet-recorder/compare/master...3.7-Update#diff-73510702485a7dd2f7000285cbd5e557R40 > > Here is the central code block that does it. Anything obviously dumb here? > > * float samples_per_second = samp_rate;* > * float syms_per_sec = 3600;* > * float gain_mu = 0.01;* > * float mu=0.5;* > * float omega_relative_limit = 0.3;* > * float offset = chan_freq - center_freq; // have to reverse it for 3.7 > because it swapped in the switch.* > * float clockrec_oversample = 3;* > * int decim = int(samples_per_second / (syms_per_sec * > clockrec_oversample));* > * float sps = samples_per_second/decim/syms_per_sec;* > * const double pi = boost::math::constants::pi<double>();* > > * cout << "Control channel offset: " << offset << endl;* > * cout << "Decim: " << decim << endl;* > * cout << "Samples per symbol: " << sps << endl;* > > * std::vector<float> lpf_taps;* > > * init_loggers(max_loggers, center_freq, samp_rate);* > > * gr::msg_queue::sptr queue = gr::msg_queue::make();* > > * lpf_taps = gr::filter::firdes::low_pass(1, samp_rate, 10000, 12000);* > > * gr::filter::freq_xlating_fir_filter_ccf::sptr prefilter = > gr::filter::freq_xlating_fir_filter_ccf::make(decim,* > * lpf_taps,* > * offset,* > * samp_rate);* > > * gr::digital::fll_band_edge_cc::sptr carriertrack = > gr::digital::fll_band_edge_cc::make(sps, 0.6, 64, 0.35);* > > * gr::analog::pll_freqdet_cf::sptr pll_demod = > gr::analog::pll_freqdet_cf::make(2.0 / clockrec_oversample, > 2*pi/clockrec_oversample, -2*pi/clockrec_oversample);* > > * gr::digital::clock_recovery_mm_ff::sptr softbits = > gr::digital::clock_recovery_mm_ff::make(sps, 0.25 * gain_mu * gain_mu, mu, > gain_mu, omega_relative_limit);* > > * gr::digital::binary_slicer_fb::sptr slicer = > gr::digital::binary_slicer_fb::make();* > > * gr::digital::correlate_access_code_tag_bb::sptr start_correlator = > gr::digital::correlate_access_code_tag_bb::make("10101100",0,"smartnet_preamble");* > > * smartnet_deinterleave_sptr deinterleave = smartnet_make_deinterleave();* > > * smartnet_crc_sptr crc = smartnet_make_crc(queue);* > > * tb->connect(src,0,prefilter,0);* > * tb->connect(prefilter,0,carriertrack,0);* > * tb->connect(carriertrack, 0, pll_demod, 0);* > * tb->connect(pll_demod, 0, softbits, 0);* > * tb->connect(softbits, 0, slicer, 0);* > * tb->connect(slicer, 0, start_correlator, 0);* > * tb->connect(start_correlator, 0, deinterleave, 0);* > * tb->connect(deinterleave, 0, crc, 0);* > > * tb->start();* > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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