湖南工业大学期末考试试卷
12(s?1)(s?5)?40e(t)ss?e(?)?limsE(s)?lims?s?0s?0ss[(s?1)(s?5)?20]?20K
2(s?1)(s?5)?402(0?1)(0?5)?4055?lim???s?0s[(s?1)(s?5)?20]?20K20K2K3 (b) finding the minimum value K1 If e (t)ss≤1.5 is desired, then K?
七、 For each of the transfer functions
G(s)?4(1?0.5) 2s(1?0.2s)(1?0.05s)55?K1?Kmin? 335?1.5, so 2K(a) draw the log magnitude (exact and asymptotic) and phase diarams; (b) draw the polar plot