*ftpplot* - Distribution of FFT coefficient values

The distribution of coefficient values for a single FFT is exponential if the original data contain no periodic signal. This distribution can be plotted and inspected. Significant coefficients will appear beyond the high-value end of the normal distributions. The width of the histogram bins can be adjusted (before running fft) to get a nice looking plot.

To plot the power density distribution created by fft.

  xt> fft.histogram_bi=0.5  # if necessary, adjust number for an aesthetic plot

  xt> ftpplot
  input table file: rp90_ftp

The plot will appear on the screen. To make hard copy, type = with cursor within plot. To return to text window type q.