学术报告：Remarks and Generalizations of Unwinding Blaschke Expansion
报告人: 钱涛 (Professor, 澳门科技大学)
时 间：2019年4月26日（星期5）下午3：30 -4：30
Typical conformal mappings in one-complex variable such as Möbius transforms, Blaschke products and starlike functions give rise to non-linear phases with non-negative phase deriva- tives, the latter being defined as instantaneous frequencies of the signals they represent. Since Gabor, 1946, the subject of analytic positive phase derivative has been attempted by signal analysts. The study of positive frequency decomposition together with applications has been shown in the literature since 2000. The directly related topic to positive analytic frequency is positive frequency decomposition of signals. The latter mainly includes the maximal selection methodology and the Blaschke product unwinding methodology. Some studies blend the two methodologies together. This talk mainly discusses the unwinding methodology. We discusses, apart from the sifting process made through the classical backward shift operation, also siftings through subtracting constants other than the averages of the functions, and sub- tracting n-Blaschke forms of the given function, aiming at larger winding numbers. Based on the minimum phase function energy front loading principle in DSP the latter are more effective unwinding methods.