Initial commitHEADmaster

* codec2 cut-down version 1.2.0
* Remove codebook and generation of sources
* remove c2dec c2enc binaries
* prepare for emscripten

1 files changed, 271 insertions, 0 deletions

diff --git a/octave/ofdm_state.m b/octave/ofdm_state.m
new file mode 100644
index 0000000..a2eca26
--- /dev/null
+++ b/octave/ofdm_state.m
@@ -0,0 +1,271 @@
+% ofdm_state.m
+%
+% Library of state machine functions for the OFDM modem
+
+1;
+
+%-------------------------------------------------------------------
+% sync_state_machine - calls mode-specific sync state state_machine
+%-------------------------------------------------------------------
+
+function states = sync_state_machine(states, rx_uw)
+  if strcmp(states.state_machine, "voice1")
+    states = sync_state_machine_voice1(states, rx_uw);
+  elseif strcmp(states.state_machine, "data")
+    if strcmp(states.data_mode, "streaming")
+      states = sync_state_machine_data_streaming(states, rx_uw);
+    else
+      states = sync_state_machine_data_burst(states, rx_uw);
+    end
+  elseif strcmp(states.state_machine, "voice2")
+    states = sync_state_machine_voice2(states, rx_uw);
+  else
+    assert(0);
+  endif
+endfunction
+
+%--------------------------------------------------------------------
+%  Due to the low pilot symbol insertion rate and acquisition issues
+%  the earlier OFDM modem waveforms (700D and 2020) need a complex
+%  state machine to help them avoid false sync.
+%--------------------------------------------------------------------
+
+function states = sync_state_machine_voice1(states, rx_uw)
+  ofdm_load_const;
+  next_state = states.sync_state;
+  states.sync_start = states.sync_end = 0;
+
+  if strcmp(states.sync_state,'search')
+
+    if states.timing_valid
+      states.frame_count = 0;
+      states.sync_counter = 0;
+      states.modem_frame = 0;
+      states.sync_start = 1;
+      next_state = 'trial';
+    end
+  end
+
+  if strcmp(states.sync_state,'synced') || strcmp(states.sync_state,'trial')
+
+    states.frame_count++;
+
+    % UW occurs at the start of a packet
+    if states.modem_frame == 0
+        states.uw_errors = sum(xor(tx_uw,rx_uw));
+
+        if strcmp(states.sync_state,'trial')
+          if states.uw_errors >= states.bad_uw_errors
+            states.sync_counter++;
+            states.frame_count = 0;
+          end
+          if states.sync_counter == 2
+            next_state = "search";
+            states.phase_est_bandwidth = "high";
+          end
+          if states.frame_count == 4
+            next_state = "synced";
+            % change to low bandwidth, but more accurate phase estimation
+            states.phase_est_bandwidth = "low";
+          end
+          if states.uw_errors < 2
+            next_state = "synced";
+            % change to low bandwidth, but more accurate phase estimation
+            states.phase_est_bandwidth = "low";
+          else
+            next_state = "search";
+          end
+        end
+
+        if strcmp(states.sync_state,'synced')
+          if states.uw_errors > 2
+            states.sync_counter++;
+          else
+            states.sync_counter = 0;
+          end
+
+          if states.sync_counter == 6
+            next_state = "search";
+            states.phase_est_bandwidth = "high";
+          end
+        end
+      end % if modem_frame == 0 ....
+
+      % keep track of where we are up to in packet
+      states.modem_frame++;
+      if (states.modem_frame >= states.Np) states.modem_frame = 0; end
+  end
+
+  states.last_sync_state = states.sync_state;
+  states.sync_state = next_state;
+endfunction
+
+
+%-------------------------------------------------------
+% data (streaming mode) state machine
+%-------------------------------------------------------
+
+function states = sync_state_machine_data_streaming(states, rx_uw)
+  ofdm_load_const;
+  next_state = states.sync_state;
+  states.sync_start = states.sync_end = 0;
+
+  if strcmp(states.sync_state,'search')
+    if states.timing_valid
+      states.sync_start = 1; 
+      states.sync_counter = 0;
+      next_state = 'trial';
+    end
+  end
+
+  states.uw_errors = sum(xor(tx_uw,rx_uw));
+
+  if strcmp(states.sync_state,'trial')
+    if states.uw_errors < states.bad_uw_errors;
+      next_state = "synced";
+      states.packet_count = 0;
+      states.modem_frame = Nuwframes;
+    else
+      states.sync_counter++;
+      if states.sync_counter > Np
+        next_state = "search";
+      end
+    end
+  end
+ 
+  % Note packetsperburst==0 we don't ever lose sync, which is useful for 
+  % stream based testing or external control of state machine
+  
+  if strcmp(states.sync_state,'synced')
+    states.modem_frame++;
+    if (states.modem_frame >= states.Np) 
+      states.modem_frame = 0; 
+      states.packet_count++;
+      if (states.packetsperburst)
+        if (states.packet_count >= states.packetsperburst)
+          next_state = "search";
+        end
+      end
+    end
+  end
+  
+  states.last_sync_state = states.sync_state;
+  states.sync_state = next_state;
+endfunction
+
+%-------------------------------------------------------
+% data (burst mode) state machine
+%-------------------------------------------------------
+
+function states = sync_state_machine_data_burst(states, rx_uw)
+  ofdm_load_const;
+  next_state = states.sync_state;
+  states.sync_start = states.sync_end = 0;
+
+  if strcmp(states.sync_state,'search')
+    if states.timing_valid
+      states.sync_start = 1; 
+      states.sync_counter = 0;
+      next_state = 'trial';
+    end
+  end
+
+  states.uw_errors = sum(xor(tx_uw,rx_uw));
+
+  % pre or post-amble has told us this is the start of the packet.  Confirm we 
+  % have a valid frame by checking the UW after the modem frames containing
+  % the UW have been received 
+  if strcmp(states.sync_state,'trial')
+    states.sync_counter++;
+    if states.sync_counter == Nuwframes
+      if states.uw_errors < states.bad_uw_errors;
+        next_state = "synced";
+        states.packet_count = 0;                          % number of packets in this burst
+        states.modem_frame = Nuwframes;                   % which modem frame we are up to in packet
+      else
+        next_state = "search";
+        % reset rxbuf to make sure we only ever do a postamble loop once through same samples
+        states.rxbufst = states.Nrxbufhistory;
+        states.rxbuf = zeros(1, states.Nrxbuf);
+      end
+    end
+  end
+  
+  if strcmp(states.sync_state,'synced')
+    states.modem_frame++;
+    if (states.modem_frame >= states.Np) 
+      states.modem_frame = 0;                           % start of new packet
+      states.packet_count++;
+      if (states.packetsperburst)
+        if (states.packet_count >= states.packetsperburst)
+          next_state = "search";                        % we've finished this burst
+          % reset rxbuf to make sure we only ever do a postamble loop once through same samples
+          states.rxbufst = states.Nrxbufhistory;
+          states.rxbuf = zeros(1, states.Nrxbuf);
+        end
+      end
+    end
+  end
+  
+  states.last_sync_state = states.sync_state;
+  states.sync_state = next_state;
+endfunction
+
+%-------------------------------------------------------
+% fast sync voice state state_machine
+%-------------------------------------------------------
+
+function states = sync_state_machine_voice2(states, rx_uw)
+  ofdm_load_const;
+  next_state = states.sync_state;
+  states.sync_start = states.sync_end = 0;
+
+  if strcmp(states.sync_state,'search')
+
+    if states.timing_valid
+      states.frame_count = 0;
+      states.sync_counter = 0;
+      states.modem_frame = 0;
+      states.sync_start = 1;
+      next_state = 'trial';
+    end
+  end
+
+  if strcmp(states.sync_state,'synced') || strcmp(states.sync_state,'trial')
+
+    states.frame_count++;
+
+    % UW occurs at the start of a packet
+    if states.modem_frame == 0
+        states.uw_errors = sum(xor(tx_uw,rx_uw));
+
+        if strcmp(states.sync_state,'trial')
+          if states.uw_errors <= states.bad_uw_errors
+            next_state = "synced";
+          else
+            next_state = "search";
+          end
+        end
+
+        if strcmp(states.sync_state,'synced')
+          if states.uw_errors > states.bad_uw_errors
+            states.sync_counter++;
+          else
+            states.sync_counter = 0;
+          end
+
+          if states.sync_counter == 6
+            next_state = "search";
+          end
+        end
+      end
+
+      % keep track of where we are up to in packet
+      states.modem_frame++;
+      if (states.modem_frame >= states.Np) states.modem_frame = 0; end
+  end
+
+  states.last_sync_state = states.sync_state;
+  states.sync_state = next_state;
+endfunction
+