Undirectional JMC actuators in the active attenuation of noise in ducts

Seppo Uosukainen, Vesa Välimäki

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    In feedforward active noise control systems in ducts, a natural solution to avoid the acoustic feedback from the cancelling actuator to the reference detector is to use a underectional actuato. New realizable ideal undirectional three- and two-element source configurations, based on the JMC method, are introducted. In the two-element actuator the elements act as a dipole with the monopole effect included in the same elements. The inter-channel delay in the control structure of the two-element actuator is optimized with three different ways. In one of them the delay element is omitted altogether. The output volume velocities of all the three variations of two-element Ideal Source are mutually identical and independent of the inter-channel delay opitmization, and also identical with those of Swinbanks' two-element actuator, although the procedure of attaining them is quite different. It turns ou to be advantageous in the practical implementation of digital control systems that the new three- and two-element solutions can be realized with no interchannel delays. Thus, it is possible to achieve simplified control algorithms and reduce the computing time or improve the performance.
    Original languageEnglish
    Pages (from-to)63-77
    Number of pages15
    JournalActa Acustica United with Acustica
    Volume85
    Publication statusPublished - 1999
    MoE publication typeA1 Journal article-refereed

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