,
Creates a psd_lst.
psd_lst(psd_tbl = NULL, segments_tbl = NULL, channels_tbl = NULL)A psd_lst.
A data table of segment numbers and related information. See segments_tbl().
Optionally a table with channels information. See channels_tbl().
A valid psd_lst.
Other psd_lst: 
is_psd_lst()