Theory and Real-Time Implementation of Time Varying Digital Audio Filters
Digital audio filters whose parameters vary with time are analyzed according to the Time-Varying filter theory. Such a theory allows for recursive filter realization using finite order difference equations with time-varying coefficients. With this approach, the errors occurring during parameter transitions can be evaluated. It was found that such errors were significant for abrupt variation in filter parameters. A real-time microprocessor implementation for such a filter is also presented. Using a novel test, the real-time output of the varying filter was evaluated, so that perceived filter transition discontinuities could be detected.
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