FAST: An extension of the Wavelet Synchrosqueezed Transform
- Samit Chakrabarty ,
- Amey Desai ,
- Thomas Richards
Abstract
Extracting frequency domain information from signals usually requires
conversion from the time domain using methods such as Fourier, wavelet,
or Hilbert transforms. Each method of transformation is subject to a
theoretical limit on resolution due to Heisenberg's uncertainty
principle. Different methods of transformation approach this limit
through different trade-offs in resolution along the frequency and time
axes in the frequency domain representation. One of the better and more
versatile methods of transformation is the wavelet transform, which
makes a closer approach to the limit of resolution using a technique
called synchrosqueezing. While this produces clearer results than the
conventional wavelet transforms, it does not address a few critical
areas. In complex signals that are com-posed of multiple independent
components, frequency domain representation via synchrosqueezed wavelet
transformation may show artifacts at the instants where components are
not well separated in frequency. These artifacts significantly obscure
the frequency distribution. In this paper, we present a technique that
improves upon this aspect of the wavelet synchrosqueezed transform and
improves resolution of the transformation. This is achieved through
bypassing the limit on resolution using multiple sources of information
as opposed to a single transform.