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Akustisk ekoutsläckare
Blekinge Institute of Technology, Department of Signal Processing.
Blekinge Institute of Technology, Department of Signal Processing.
1996 (English)Independent thesis Advanced level (degree of Master (One Year))Student thesis
Abstract [en]

This Masters thesis report evaluates a method of acoustic echo cancellation in a hands-free mobile phone system. The method uses an adaptive subband filter architecture to get a faster convergence rate and adaptive FIR filters that are easy to handle. The filter bank that split the signal is employing a shorter FIR-filter than what i suggested in the literature. This has resulted in improves echo suppression and faster convergence rate. Simulations in Matlab and implementation in an DSP (Digital Signal Processor) has been performed. An echo cancellation of about 32 dB was achieved from simulations, the used signals were real signals recorded in a car. The simulations show a faster convergence rate compared to a fullband LMS-flter.

Abstract [en]

Detta magistersarbet utvärderar en metod för undertryckning av den akustiska ekovägen i ett "hands-free" mobiltelefonsystem. Metoden tillämpar delbandsindelsning för att få ett adaptivt system som konvergerar snabbt samt få kortare filterlängder på de adaptiva filtren. Filterbanken som delar upp signalen använder kortare FIR-filter än vad som föreslagits i litteraturen. Detta har resulterat i en bättre undertryckning av ekot och snabbare konvergens. Simulering i Matlab och implementering i en DSP (Digital Signal Processor) har utförts. Genom att använda en undertryckning på ca 32 dB uppnåddes vid simulering med signaler inspelade i en bilkupé. Simuleringen visar även att en snabbare konvergens uppnås jämfört med då ett fullbands LMS-filter används.

Place, publisher, year, edition, pages
1996. , 13 p.
Keyword [en]
akustiska ekovägen, Digital Signal Processor
National Category
Signal Processing
URN: urn:nbn:se:bth-2959Local ID: diva2:830254
Available from: 2015-04-22 Created: 2003-11-11 Last updated: 2015-06-30Bibliographically approved

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