The error signal is then Q|c(0=-(0)y(02=(-c") (3-3-7) As t approaches the infinity, the error signal approaches t le 2022-2-3 82022-2-3 8 The error signal is then       1  t e t r t y t e        As approaches the infinity, the error signal approaches , i.e., t  e      (3-3-7)