TITLE:
Time-Varying Bandpass Filter Based on Assisted Signals for AM-FM Signal Separation: A Revisit
AUTHORS:
Guanlei Xu, Xiaotong Wang, Xiaogang Xu, Lijia Zhou, Limin Shao
KEYWORDS:
Time-Varying Bandpass Filter (TVBF); Hilbert Tranform; Assisted Signal; AM-FM Component; Time-Frequency Distribution (TFD)
JOURNAL NAME:
Journal of Signal and Information Processing,
Vol.4 No.3,
July
30,
2013
ABSTRACT:
In this
paper, a new signal separation method mainly for AM-FM components blended in
noises is revisited based on the new derived time-varying bandpass filter
(TVBF), which can separate the AM-FM components whose frequencies have
overlapped regions in Fourier transform
domain and even have crossed points in time-frequency distribution (TFD)
so that the proposed TVBF seems like a “soft-cutter” that cuts the frequency
domain to snaky slices with rational physical sense. First, the Hilbert
transform based decomposition is analyzed for the analysis of nonstationary
signals. Based on the above analysis, a hypothesis under a certain condition
that AM-FM components can be separated successfully based on Hilbert transform
and the assisted signal is developed, which is supported by representative
experiments and theoretical performance analyses on a error bound that is shown
to be proportional to the product of frequency width and noise variance. The
assisted signals are derived from the refined time-frequency distributions via
image fusion and least squares optimization. Experiments on man-made and
real-life data verify the efficiency of the proposed method and demonstrate the
advantages over the other main methods.