Characterization of zeros in two-frequency-scale systems

We study the asymptotic behavior of the zeros of a two-frequency-scale transfer function in terms of the zeros of its slow and fast transfer functions. By introducing the notion of type index, we will show that all zeros of a two-frequency-scale transfer function with the type index of either /spl nu//spl ges/0 or /spl nu/=-1 can be completely characterized in a manner that is quite similar to the characterization of the poles. We also give a partial characterization for all other zeros in terms of the cardinality of their zero sets.<
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