A ``short'' FFT

Small numbers ( $\leq 2^{14}$) of time bins may be analyzed directly from the output of ltcurv.

input file: rp90_ltc.tab

output files: rp90_fft.tab, rp90_ftp.tab, rp90_pwr.tab

  xt> fft 
  Input source file (table or timsorted qpoe file): rp90_ltc
  root name for output file [root_fft(ftp,pwr).tab]: .  # will assign root name
                                                 or rp90

  Input table column heading:  src    # label of column giving number of counts

  FFT done with 512 bins!
  Creating raw fft output file: rp90_fft.tab                         # columns:
                                         # freq, rfreq, ifreq, power, normpower
  Creating histogram output file: rp90_ftp.tab         # columns: logel,  phist
  Creating fft power output file: rp90_pwr.tab                       # columns:
                                                  # bin, freq, power, normpower
  xt>

To list only significant coefficients, run timprint as in §8.6 with the _pwr.tab file as input.