2016 2
nd
International Conference on Mechanical, Electronic and Information Technology Engineering (ICMITE 2016)
ISBN: 978-1-60595-340-3
Bi-dimensional Generalized Uncertainty Relations Associated with
Hilbert Transform in LCT Domain
Xu Guanlei*, Shao Limin, Wang Xiaotong, Xu Xiaogang
Navigation Department of Dalian Navy Academy, Dalian, China, 116018
*xgl_86@163.com
Keywords: uncertainty relation; linear canonical transform (LCT); generalized Hilbert transform
(GHT); complex signals
Abstract. This paper discusses the Heisenberg’s uncertainty relations associated with two types of
2D LCT (linear canonical transform). These uncertainty bounds are related with the transform
parameters of LCT. In addition, we show that the certainty bounds for the complex signals derived by
LCT are different with that for the general complex signals in most cases. The special cases of these
principles in traditional domains are provided as well. First, these new uncertainty relations enrich the
ensemble of uncertainty principles. Second, these derived bounds yield new viewpoint of complex
signals via 2D Hilbert transform.
1 Introduction
Heisenberg’s uncertainty principle plays an important role in mathematics, physics, signal
processing and information theory and so on. There have been many extensions [1-13] of traditional
Heisenberg’s uncertainty principle [14-16] in these fields or new transform domains [17-29].
Recently, there are many papers, such as [2-13], involving new various uncertainty principles in new
transform domains. However, none of them has covered the uncertainty principles associated with
Hilbert transform in linear canonical transform (LCT) domain, that is to say, the uncertainty principle
for the complex signals derived by Hilbert transform have not been involved despite of some
discussions of Heisenberg’s uncertainty principle on new transform for general complex signals
[1,3,4,9,12,13].
Hilbert transform [17-21] is an elementary tool in signal analysis and is of very much importance to
communication and time-frequency analysis. The complex signal, derived from Hilbert transform, is
different from the general complex signal and widely used in many fields such as communication,
optics and radar theory. Therefore, there is great need to discuss the uncertainty principles for the
complex signals derived by Hilbert transform. In this paper, we will discuss the uncertainty principles
for the complex signals derived by Hilbert transform in 1D and 2D LCT domains. Without loss of
generality and for the sake of simpliness, we assume that all the means are zeros in any domains in
this paper.
As the generalization of the traditional Fourier transform (FT), FRFT [22,25], LCT [22,23,24] has
some properties with its transform parameter and sometimes gives better signal analysis results. More
details can be found in [22-25]. Here we only briefly review its definition.
2D LCT is the generalization of the classical 2D Fourier transform. The LCT of one real function
),( yxf ( yx, ) is defined as follow:
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