山东大学2014-2015学年2学期数字信号处理（双语）课程试卷（) 将分侧撸人 4.(20 pts)Let Y(e)denote the Fourier transform of the sequencexn]=()"un].LetyIn]denote a finite-duration sequence of length 10,ie.,yin]=0,n<0,and yIn]=0,n210.The 10-point DFT ofyn denoted by YTk],corresponds to 10 equally spaced samples of Y(e),ie. 签 Y(k)=X(en).(a)Calculate X(e)(b)Determine y[n]from Y(). 琴 第3负共5页2014-2015 2 数字信号处理（双语） （A） 3 5 4．(20 pts) Let denote the Fourier transform of the sequence . Let y[n] denote a finite-duration sequence of length 10, i.e., y[n]=0, n<0, and y[n]=0, n≥10. The 10-point DFT of y[n], denoted by Y[k], corresponds to 10 equally spaced samples of , i.e. . (a) Calculate ; (b) Determine y[n] from Y (k). 得分 阅卷人 ( ) j X e 1 2 [ ] ( ) [ ] = n x n u n 2 /10 ( ) ( )  = j k Y k X e ( ) j X e ( ) j X e