M.Greitans and R.Shavelis, “Extended Fourier series for time-varying filtering and reconstruction from level-crossing samples”, EUSIPCO 2013, Marrakech, Morocco, 9-13 September, 2013.

In this paper an extension of the classical Fourier series for
analysis of non-stationary signals with time-varying spectral
content is presented. This, in comparison to the classical series,
allows reducing the number of Fourier coefficients required
to represent the signal. The proposed extended Fourier
series can be used for time-varying filtering, which in turn can
be used for recovery of the signals from level-crossing samples.
This has been demonstrated by numerical simulations


on different test signals.