shallow zip-file copy from codec2 e9d726bf20

1 files changed, 69 insertions, 0 deletions

diff --git a/octave/cohpsk_demod_plot.m b/octave/cohpsk_demod_plot.m
new file mode 100644
index 0000000..22291ad
--- /dev/null
+++ b/octave/cohpsk_demod_plot.m
@@ -0,0 +1,69 @@
+% cohpsk_demod_plot.m
+% David Rowe May 2015
+%
+% Plot Octave outputs from cohpsk_demod, c2dec, to visualise what's going on
+% when errors hit the system
+
+#{
+   $ ./cohpsk_get_test_bits - 5600 | ./cohpsk_mod - - | ./ch - - --No -40 | ./cohpsk_demod - - -o cohpsk_demod.txt | ./cohpsk_put_test_bits -
+   octave> cohpsk_demod_plot("../build_linux/src/cohpsk_demod.txt")
+#}
+   
+function cohpsk_demod_plot(fn)
+  Nc=7; Nd=2; Ns=6;
+
+  load(fn);
+
+  Ncf = 100;     % number of codec frames to plot
+  Nmf = Ncf/2;  % number of modem frames to plot
+  Nms = Nmf*Ns; % number of modem symbols to plot
+
+  figure(1)
+  clf;
+
+  % plot combined signals to show diversity gains
+
+  combined = rx_symb_log_c(:,1:Nc);
+  for d=2:Nd
+    combined += rx_symb_log_c(:, (d-1)*Nc+1:d*Nc);
+  end
+  plot(combined*exp(j*pi/4)/sqrt(Nd),'+')
+  title('Scatter');
+  axis([-2 2 -2 2])
+
+  figure(2)
+  clf;
+  subplot(211)
+  plot(rx_phi_log_c(1:Nms,:))
+  title('phase')
+  axis([1 Nms -pi pi])
+  subplot(212)
+  plot(rx_amp_log_c(1:Nms,:))
+  title('amplitude')
+  axis([1 Nms 0 1])
+
+  figure(3)
+  subplot(211)
+  plot(rx_timing_log_c)
+  title('rx timing');
+  subplot(212)
+  stem(ratio_log_c)
+  title('Sync ratio');
+
+  figure(4)
+  plot(f_est_log_c - 1500)
+  title('freq offset est');
+  axis([1 Nmf -50 50])
+
+  figure(5)
+  y = 1:Nms;
+  x = 1:Nc*Nd;
+  z = 20*log10(rx_amp_log_c(1:Nms,:));
+  mesh(x,y,z);
+  grid
+  title('Channel Amplitude dB');
+  a = min(min(z));
+  b = max(max(z));
+  axis([1 Nc*Nd 1 Nms a b])
+end
+