4. Quadratic time-frequency representations

4.1 Quadratic transformations for RTF

We consider deterministic permanent time signals, real or complex scalars.

Various quadratic transformations can be used to generate a second category of time-frequency representations (RTFs), known as quadratic representations (see table 4 ), which can be interpreted in energetic terms. Such a quadratic RTF (RTF-Q), also known as a bilinear RTF, can be considered as the restriction to X _i = X _j ...