I have been using procedure FFTC1D and FFTC1DInv successfully to filter a series of samples in a Delphi program. In the same program I have created a second, analog procedure but this one gives problems: the outcome does not correspond to my expectations. Further investigations gives me hope: shifting the outputsignal half the total length of the series gives a result that corresponds to my expectations. Question: Is this normal behavior (and if so: when does this occur) or am I doing something wrong?
Remark: I realize that when the signal is made continuous bij replicating the series the result may be considered as normal: the output will be replicated too.
The environment: Windows 7, Delphi 7.0
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