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| Artikel-Nr.: 858A-9783642036385 Herst.-Nr.: 9783642036385 EAN/GTIN: 9783642036385 |
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| The requirement of causality in system theory is inevitably accompanied by the appearance of certain mathematical operations, namely the Riesz proj- tion,theHilberttransform,andthespectralfactorizationmapping.Aclassical exampleillustratingthisisthedeterminationoftheso-calledWiener?lter(the linear, minimum means square error estimation ?lter for stationary stochastic sequences [88]). If the ?lter is not required to be causal, the transfer function of the Wiener ?lter is simply given by H(?)=? (?)/? (?),where ? (?) xy xx xx and ? (?) are certain given functions. However, if one requires that the - xy timation ?lter is causal, the transfer function of the optimal ?lter is given by 1 ? (?) xy H(?)= P ,?? (??,?] . + [? ] (?) [? ] (?) xx + xx? Here [? ] and [? ] represent the so called spectral factors of ? ,and xx + xx? xx P is the so called Riesz projection. Thus, compared to the non-causal ?lter, + two additional operations are necessary for the determination of the causal ?lter, namely the spectral factorization mapping ? ? ([? ] ,[? ] ),and xx xx + xx? the Riesz projection P . Weitere Informationen: | | Author: | Volker Pohl; Holger Boche | Verlag: | Springer Berlin | Sprache: | eng |
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| Weitere Suchbegriffe: Multi-Antenna Systems, Packet Radio Networks, QoS Opimization, Quality of Service, Radio Access Networks, Scheduling, Signal Processing, communication, system, systems theory |
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