Frequency response envelopes of a family of uncertain continuous-time systems

Amplitude and phase envelopes of a family of interval rational transfer functions of continuous-time systems are derived. A finite number of intervals on the real frequency axis are explicitly determined, for which the maximum and the minimum amplitude or phase of the functions, with respect to the interval coefficients, coincide with explicit fixed coefficients functions. Some special cases where simplifications are applicable, are pointed out. Illustrative examples that are consistent with the derived results are provided.<
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