Übersicht:Es wird ein Verfahren zur Identifikation von Multirate-Systemen vorgestellt, das eine direkte Schätzung des unbekannten Systems ohne die sonst erforderlichen Entfaltungsalgorithmen ermöglicht Den Zugang dafür liefert eine modifizierte Modellstruktur für die Identifikation, die den Besonderheiten der Signalverarbeitung in Multirate-Systemen angepaßt ist. Es werden experimentelle Ergebnisse bei der Anwendung des Identifikationsverfahrens für die Echokompensation in Teilnehmeranschlußschaltungen mitgeteilt.Abstract: An Identification method for multirate systems is proposed which is suitable for direct estimation of the unknown system without any numerical requirements for deconvolution. This is achieved by designing a matched model system in accordance to the multirate properties of the original system. The identification method is applied to echo cancellation in digital subscriber line interface circuits.Some experimental results are presented.Für die Dokumentation: Multirate-System / Identifikation / Echokompensation / adaptive Filter

Identifikation in Multirate-Systemen mittels mehrkanaliger schneller Transversalfilter 201 ConclusionA large-signal numerical model for a four level laser system has been described which is suitable for analysis of a Pr 3+ -doped fluoride fibre amplifier. This model takes into account the radial field distribution of the LP 01 mode in step-index single-mode fibre, realistic stimulated emission and signal excited state absorption cross-sections and the wavelength dependent fibre loss due to the signal ground state absorption. Small-signal and large-signal properties of a PDFFA have been investigated using this model. It has been found that the best performance is obtained when the cutoff wavelength of the LP^ mode is 750 nm, independent of fibre numerical aperture, input pump and signal power. Numerical aperture should be chosen as high as possible. Codirectional, counterdirectional and bidirectional pumping have been investigated and found to give equal amplification due to the lack of pump ES A. The effect of Pr 3+ confinement on smallsignal PDFFA operation has been studied. A 2 dB gain improvement has been predicted when the radius of the Pr 3+ -doped region is 65% of the fibre core.This work has been supported by the Alexander-von-Humboldt-Stiftung, References: [1] Zemon, S.; Pedersen, B; Umbert, G.; Miriscalco, W.J.; Hau, R T.; Folweiler, R.C.; Thomson, .; Andrews, L.J.: Exciled-state-ahsorpfion cross sections ud amplifier modeling in the 1300-nm region for Nd-doped glasses. IEEE Photon. TechuoL Lett. voL 4 (1992) pp. 244-247. [2] Ohishi, V.; Kanamori, T.; Nishi, T.; Takahashi, S.: A high gain, high onlpot saturation power Pr 3+ -doped fluoride fiber amphTier at IJ.ro. IEEE Photo» TechnoL Lett. ToL 3 (1991) pp. 715-717. [3] Ohishi, Y.; Kanamori, T.; Kitagawa, T.; Takahashi, S.; Saitzer, E.; SigeL G.H.: Pr s+ -doped fluoride fiber ampUOer operating at IJl urn. In Proc. of Conference on Optical Fiber Commmkation OFC *91, Washington DC 1991, paper PD2. [4] Miyajuna, Y.: Sngawa, T.; Fukusaku, Y.: 38J db amplification at 1 Jl urn and possibility of 0.98»m pumping in Pr 3 *-doped fluoride fibre. Electron. Lett. ToL 27 (1991) pp. 1706-1707. [5] Ohishi, Y.; Kanamori, T.; Temmyo, J.; Wada, M.; Yamada, M.; Shimizu, M; Yoduno, K.; Hanafnsa. H.; Horiguchi, M; Takahashi, S.: Laser diode pumped Pr>*-doped and Pr"-Yb"-codoped fluoride fibre amplifiers operating at 13nm. [6] Lobbett, R.; Wy.tt, R.; Eanfley, P.; Whitky. T.; Smyth, T. J.; Siebest«, D.; Carter, S.F.; Davey, S.T.; Millar, CA.; Brierlev, M.G.: System characterisation of high gain and high saturated output power Pr 3 *-doped fluororirconale fibre amplifier at U nm. Es wird ein schnelles Verfahren zur Identifikation in Multirate-Systemen vorgestellt Dieses basiert auf einer angepaßten Identifikationsanprdnung und einer mehrkanaligcn Version des FTF-Algorithmus und setzt eine geeignete Signalbeschreibung des Modellsystems voraus. Es werden Ergebnisse aus einer experimentellen Anwendung zur Echokompensation in Teilnehmeranschlußschaltungen dargestellt.Abstract: A fas...