山东大学2015-2016学年2学期数字信号处理（双语）课程试卷(A) 海分侧卷人 4.(15 pts)The system functionofa discrete-time filter is 4 2 H()=1e41-e Assume that this discrete-time filter was designed by the impulse invariance method with Ta=2;i.e.,h[n]=2/c(2n),where real hc(t)is the unit impulse response of the continuous-time filter that coul have been the basis for the design.Find the system function Hc(s)of ho(t).Is 都 your answer unique?Ifnot,find another system function Hc(s). 分侧卷人 3.(5 pts)A sequence x[n]is as the following figure: x[n] ◆一 0 Determine 5-point DFT X[k]ofthe sequence x[n]. 器 第2项共4页2015-2016 2 数字信号处理（双语） （A） 2 4 3．(5 pts) A sequence x[n] is as the following figure : Determine 5-point DFT X[k] of the sequence x[n]. 4．(15 pts) The system function of a discrete-time filter is ( ) 0.6 1 0.4 1 4 2 1 1 H z e z e z − − − − = − − − . Assume that this discrete-time filter was designed by the impulse invariance method with Td=2; i.e., h[n] =2hC(2n), where real hC(t) is the unit impulse response of the continuous-time filter that could have been the basis for the design. Find the system function Hc(s) of hC(t). Is your answer unique? If not, find another system function Hc(s). 得分 阅卷人 得分 阅卷人 x n[ ]