code: def plot_freq(self, x, y, title='', ylabel=None, scale='semilogy'):
          
          freq = self.frequency
          scaling = freq['scaling'].get_value()
  
          if ylabel is None:
              if freq['complex'].get_value():
                  ylabel = 'Amplitude (uV)'
              elif 'power' == scaling:
                  ylabel = 'Power spectral density (uV ** 2 / Hz)'
              elif 'energy' == scaling:
                  ylabel = 'Energy spectral density (uV ** 2)'
  
          self.parent.plot_dialog = PlotDialog(self.parent)
          self.parent.plot_dialog.canvas.plot(x, y, title, ylabel, scale=scale)
          self.parent.show_plot_dialog()
docs: Plot mean frequency spectrum and display in dialog.
  
          Parameters
          ----------
          x : list
              vector with frequencies
          y : ndarray
              vector with amplitudes
          title : str
              plot title
          ylabel : str
              plot y label
          scale : str
              semilogy, loglog or linear