Analytic Curve Frequency-Sweeping Stability Tests for Systems with Commensurate Delays Li, Xu-Guang

frequency domain. As part of the design procedure, modified Nyquist–Hall and Nichols diagrams are presented

Sensitivity -- 35 Butterworth filter -- 36 Frequency response -- 37 Signal to noise ratio; tradability -- 38

Triangularizations for Non-Linear Control Systems.- On-Line Frequency Estimation of Periodic Signals.- Power Based