Spectral design of output feedback controllers for systems pre-compensated by input shapers∗∗The presented research has been supported by the Czech Science Foundation under the project No. 13–06962S, by the Programme of Interuniversity Attraction Poles of the Belgian Federal Science Policy Office(IAP P6–DYSCO), by OPTEC, the Optimization in Engineering Center of the KU Leuven, and the project G.0712.11N and G.0717.11N of the Research Foundation –Flanders (FWO).