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();
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