Generalized mixed-/spl mu/ bounds for real and complex multiple-block uncertainty with internal matrix structure

New absolute stability results that unify and extend existing structured singular value bounds for mixed uncertainty are developed using the multivariable Nyquist criterion. These bounds generalize prior upper bounds for mixed-/spl mu/ by permitting the treatment of nondiagonal real uncertain blocks as well as accounting for internal matrix structure in the uncertainty. Several specializations to well known absolute stability criteria from the classical literature are given which allows for a systematic comparison of these results in addressing the problem of robust stability for real parameter uncertainty.