The Discrete Fourier Transform (DFT) of a signal
may be defined by
' means ``is defined as'' or ``equals by definition'', and
The sampling interval is also called the sampling period.
For a tutorial on sampling continuous-time signals to obtain
non-aliased discrete-time signals, see Appendix D.
When all signal samples are real, we say
If they may be complex, we write
means is any integer.
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