The problem of reconstructing a signalφ(x) from its magnitude |φ(x)] isof considerable interest to engineers and physicists. This article concerns the problem of determining a time-limited signal f with period ...The problem of reconstructing a signalφ(x) from its magnitude |φ(x)] isof considerable interest to engineers and physicists. This article concerns the problem of determining a time-limited signal f with period 2π when |f(eix)l is known for x∈[-π,π]. It is shown that the conditions |g(eix)| = |f(eix)| and |g(ci(x+b)) -g(eix)| =f(ei(x+b)) - f(eix)|, b ≠ 27π, together imply that either g = wf or g = v f, where both w and v have period b. Furthermore, if b/2π is irrational then the functions w and v b is rational then w takes the form reduce to some constants c1 and c2, respectively; ifb/2π is rational then w takes the form w=elexB1(e1x)B2(elx)and v takes the form ei(x2πN/b+a)B1(elx)B2(elx),where B1 and B2 are Blaschke products.展开更多
A random functional central limit theorem is obtained for processes of partial sums andproduct sums of linear processes generated by non-stationary martingale differences. It devel-ops and improves some corresponding ...A random functional central limit theorem is obtained for processes of partial sums andproduct sums of linear processes generated by non-stationary martingale differences. It devel-ops and improves some corresponding results on processes of partial sums of linear processesgenerated by strictly stationary martingale differences, which can be found in [5].展开更多
基金Supported by Foundation of Hubei Educational Committee (Q20091004)NSFC (10771053)+1 种基金the National Research Foundation for the Doctoral Program of Higher Education of China (SRFDP) (20060512001)Natural Science 373 Foundation of Hubei Province (2007ABA139)
文摘The problem of reconstructing a signalφ(x) from its magnitude |φ(x)] isof considerable interest to engineers and physicists. This article concerns the problem of determining a time-limited signal f with period 2π when |f(eix)l is known for x∈[-π,π]. It is shown that the conditions |g(eix)| = |f(eix)| and |g(ci(x+b)) -g(eix)| =f(ei(x+b)) - f(eix)|, b ≠ 27π, together imply that either g = wf or g = v f, where both w and v have period b. Furthermore, if b/2π is irrational then the functions w and v b is rational then w takes the form reduce to some constants c1 and c2, respectively; ifb/2π is rational then w takes the form w=elexB1(e1x)B2(elx)and v takes the form ei(x2πN/b+a)B1(elx)B2(elx),where B1 and B2 are Blaschke products.
基金the National Natural Science Foundation of China(No.10271087).
文摘A random functional central limit theorem is obtained for processes of partial sums andproduct sums of linear processes generated by non-stationary martingale differences. It devel-ops and improves some corresponding results on processes of partial sums of linear processesgenerated by strictly stationary martingale differences, which can be found in [5].