graphics_toolkit("qt")
  d = 4;                                    % amount to add to text sizes
  set(0, "DefaultFigureColor",.94*[1 1 1])  % This coloring between subplots does not show up in the .svg output.
  set(0, "DefaultAxesFontsize",12+d)        % size of numeric tick labels
  set(0, "DefaultTextFontsize",12+d)

  T = 0.01;			          % seconds per sample
  sam_per_sec = 1/T;
  N = 128;			          % number of frequency samples
  N2 = N/2;
  Hz_per_bin = sam_per_sec/N  % no semi-colon, so value is displayed in Octave command window
  L = 11;				      % pulse_width (samples)
  L2 = (L-1)/2;

  s = [ones(1,L) zeros(1,N-L)];  % Zero-fill the signal so a DFT produces N frequency samples.
  S = fft(circshift(s,-L2));     % Rotate s() to take advantage of symmetry.  S() is therefore real-valued.

  hfig = figure("position",[1 1 1000 800]);
  subplot(2,1,1)
  plot((-N2:N2-1)*T, circshift(s,N2-L2), "linewidth",3)   % Center the pulse at 0 seconds.
  xlim([-N2 N2-1]*T)
  ylim([0 2])
  title("Signal", "fontsize",14+d)
  xlabel("Actual time (seconds)", "fontsize",12+d)

  subplot(2,1,2)
  plot(0:N2-1, S(1:N2))                                         % Plot the discrete-time Fourier transform.
  hold on
  plot(0:N2-1, S(1:N2), ".", "markersize",12, "color","blue")   % Overlay the DTFT samples.
  xlim([0 N2-1])
  set(gca, "xaxislocation","origin")
  set(gca, "xtick",0:10:N2-1)	                         %, "fontsize",12) ~ optional code
  title("Fourier transform samples", "fontsize",14+d)
  xlabel("Normalized frequency (0.7812 Hz/bin)")