Acta mathematica scientia,Series B ›› 2010, Vol. 30 ›› Issue (1): 39-46.doi: 10.1016/S0252-9602(10)60020-3

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PHASE RETRIEVAL OF TIME-LIMITED SIGNALS

FU Ying-Xiong, LI Luo-Qing   

  1. Hubei Key Laboratory of Applied Mathematics, Hubei University; Faculty of Mathematics and Computer Science, Hubei University, Wuhan 430062, China
  • Received:2008-08-29 Online:2010-01-20 Published:2010-01-20
  • Supported by:

    Supported by Foundation of Hubei Educational Committee (Q20091004), in part by NSFC (10771053), by the National Research Foundation for the Doctoral Program of Higher Education of China (SRFDP) (20060512001) and by Natural Science 373 Foundation of Hubei Province (2007ABA139).

Abstract:

The problem of reconstructing a signal φ(x) from its magnitude |φ(x)| is of considerable interest to engineers and physicists. This article concerns the problem of determining a time-limited signal f with period 2π when |f(eix)| is known for x ∈[-π, π]. It is shown that the conditions |g(eix)|=|f(eix)| and |g(ei(x+b))-g(eix)|=|f(ei(x+b))-f(eix)|, b≠2π, together imply that either g=wf or g=vf, where both w and v have period b. Furthermore, if b/2π is irrational then the functions w and v reduce to some constants c1 and c2, respectively;  if b/2π is rational then  w takes the form w=eB1(eix}B2(eix) and v takes the form ei(x2πN/b+α)B1(eix)B2(eix), where B1 and B2 are Blaschke products.

Key words: phase retrieval, time-limited signal, Blaschke product, Hardy space on the unit circle

CLC Number: 

  • 30D50
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