Luxey wrote:
To clarify my thinking, seams if you apply function twice it does nos shift signal in phase for 180deg, but rather reverses it.
When the Hilbert transform is applied twice in succession to a function
u, the result is negative u:
H(H(u))(t) = -u(t),
provided the integrals defining both iterations converge in a suitable
sense. In particular, the inverse transform is ˆ’H.
http://en.wikipedia.org/wiki/Hilbert_transform
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Les Cargill