| G13CAF | Univariate time series, smoothed sample spectrum using rectangular, Bartlett, Tukey or Parzen lag window |
| G13CBF | Univariate time series, smoothed sample spectrum using spectral smoothing by the trapezium frequency (Daniell) window |
| G13CCF | Multivariate time series, smoothed sample cross spectrum using rectangular, Bartlett, Tukey or Parzen lag window |
| G13CDF | Multivariate time series, smoothed sample cross spectrum using spectral smoothing by the trapezium frequency (Daniell) window |