The function takes a single input source containing univariate series instances or multivariate series instances. The series contain Fourier coefficients produced by a previous TD_DFFT call or some other method. The input series has elements that are in rectangular (real, imaginary) or polar (amplitude, phase) form.
The input source can be passed in using either an ART_SPEC or SERIES_SPEC. If the input source table for TD_IDFFT is not referenced using an ART_SPEC, then the Fourier coefficient results in the table must be in the RAW format. Use TD_DFFTCONV to convert the results from HUMAN_READABLE to RAW format prior to using TD_IDFFT.