filter_plot.cpp

Output

Source

#include "sigpack.h"

using namespace arma;
using namespace sp;
int main()
{
  gplot gp;
  gp.window("Filter plots", 10, 10, 700, 700);

  vec Mg(1024);
  vec Ph(1024);
  vec a, b;
  a << 1 << endr;
  b  = fir1(44, 0.25);
  Mg = 20 * log10(freqz(b, a, 1024));
  Ph = phasez(b, a, 1024);

  // Plot
  gp.set_term("qt");
  gp.grid_on();
  gp.send2gp("set multiplot layout 2, 1");
  gp.send2gp("set xtics (\"0\" 1,\"0.5\" 512,\"1\" 1024)"); // Direct call to
                                                            // gnuplot pipe
  gp.ylabel("Magnitude [dB]");
  gp.xlabel("Frequency [f/Fs]");
  gp.plot_add(Mg, "Filter");
  gp.plot_show();
  gp.send2gp("set xtics (\"0\" 1,\"0.5\" 512,\"1\" 1024)"); // Direct call to
                                                            // gnuplot pipe
  gp.ylabel("Phase [rad]");
  gp.xlabel("Frequency [f/Fs]");
  gp.plot_add(Ph, "Filter");
  gp.plot_show();
  gp.send2gp("unset multiplot");

  return 0;
}