hack: demodulate TCH_C1 bursts

include/iridium/CMakeLists.txt

@@ -15,6 +15,7 @@ install(FILES
     iuchar_to_complex.h
     tagged_burst_to_pdu.h
     burst_downmix.h
+    burst_downmix_next.h
     pdu_null_sink.h
     iridium_qpsk_demod.h
     pdu_round_robin.h

include/iridium/burst_downmix_next.h

@@ -0,0 +1,63 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2020 Free Software Foundation, Inc.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_IRIDIUM_BURST_DOWNMIX_H
+#define INCLUDED_IRIDIUM_BURST_DOWNMIX_H
+
+#include <gnuradio/block.h>
+#include <iridium/api.h>
+
+namespace gr {
+namespace iridium {
+
+/*!
+ * \brief <+description of block+>
+ * \ingroup iridium
+ *
+ */
+class IRIDIUM_API burst_downmix_next : virtual public gr::block
+{
+public:
+    typedef std::shared_ptr<burst_downmix_next> sptr;
+
+    /*!
+     * \brief Return a shared_ptr to a new instance of iridium::burst_downmix_next.
+     *
+     * To avoid accidental use of raw pointers, iridium::burst_downmix_next's
+     * constructor is in a private implementation
+     * class. iridium::burst_downmix_next::make is the public interface for
+     * creating new instances.
+     */
+    static sptr make(int output_sample_rate,
+                     int search_depth,
+                     size_t hard_max_queue_len,
+                     const std::vector<float>& input_taps,
+                     const std::vector<float>& start_finder_taps,
+                     bool handle_multiple_frames_per_burst);
+
+    virtual uint64_t get_n_dropped_bursts() = 0;
+    virtual size_t get_input_queue_size() = 0;
+    virtual void debug_id(uint64_t id) = 0;
+};
+
+} // namespace iridium
+} // namespace gr
+
+#endif /* INCLUDED_IRIDIUM_BURST_DOWNMIX_H */

lib/CMakeLists.txt

@@ -16,6 +16,7 @@ list(APPEND iridium_sources
     iuchar_to_complex_impl.cc
     tagged_burst_to_pdu_impl.cc
     burst_downmix_impl.cc
+    burst_downmix_next_impl.cc
     pdu_null_sink_impl.cc
     iridium_qpsk_demod_impl.cc
     pdu_round_robin_impl.cc

lib/burst_downmix_impl.cc

@@ -733,6 +733,7 @@ int burst_downmix_impl::process_next_frame(float sample_rate,
     pdu_meta = pmt::dict_add(pdu_meta, pmt::mp("id"), pmt::mp(sub_id));
     pdu_meta = pmt::dict_add(pdu_meta, pmt::mp("noise"), pmt::mp(noise));
     pdu_meta = pmt::dict_add(pdu_meta, pmt::mp("magnitude"), pmt::mp(magnitude));
+    pdu_meta = pmt::dict_add(pdu_meta, pmt::mp("next"), pmt::mp(false));
 
     if (d_debug) {
         printf("center_frequency=%f, uw_start=%u\n", center_frequency, uw_start);