Notation and Terminology
If

is the
DFT of

, we say that

and

form a
transform
pair and write

Another notation we'll use is
If we need to indicate the length of the DFT explicitly, we will write

and

.
As we've already seen,
time-domain signals are consistently denoted
using
lowercase symbols such as ``

,'' while
frequency-domain
signals (
spectra), are denoted in
uppercase (``

'').
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