第五、六章线性系统的频域分析与校正习题与解答5-1试求下图 (a)、(b)网络的频率特性
解 (a)依图:2121111212111111221)1(11)()(RRCRRTCRRRRKsTsKsCRsCRRRsUsUrc11121212121)1()()()(jTjKCRRjRRCRRjRjUjUjGrca(b) 依图:CRRTCRsTssCRRsCRsUsUrc)(1111)()(21222222122221211)(11)()()(jTjCRRjCRjjUjUjGrcb5-2某系统结构图如图所示,试根据频率特性的物理意义,求下列输入信号作用时,系统的稳态输出)(tcs和稳态误差)(tes(1)ttr2sin)((2))452cos(2)30sin()(tttr解系统闭环传递函数为:21)(ss频率特性:2244221)(jjj幅频特性:241)( j相频特性:)2arctan()(系统误差传递函数:,21)(11)(sssGse则)2arctan(arctan)(,41)(22jjee(1)当ttr2sin)(时, 2,rm=1 则,35
081)(2j45)22arctan()2( j4
1862arctan)2(,79
085)(2jjee)452sin(35
0)2sin()2(ttjrcmss)4
182sin(79
0)2sin()2(ttjreeemss(2) 当)452cos(2)30sin()(tttr时:2,21,12211mmrr5
26)21arctan()1(45
055)1(jj4
18)31arctan()1(63
0510)1(jjee)]2(452cos[)2()]1(30sin[)1()(jtjrjtjrtcmms)902cos(7
3sin(4
0tt)]2(452cos[)2()]1(30sin[)1()(jtjrjtjr