It is not tough to see that you may perhaps use the functionality freq resp you wrote in Lab 5 to determine the DTFT of any finite-size signal (why?). Hereafter in this lab, rename the your freq resp 淘宝和中介们一般都会打着各种五花八门的招牌引流，一篇论文几百块就能搞定，但你有没有想过，一旦出了问题，付出极低廉成本并赚取相对丰厚利润的他们，不会在乎你这个淹没在每天成百上千订单的一个人... https://mediafiremax.com/story12868517/the-%E8%AE%BA%E6%96%87%E4%BB%A3%E5%86%99-diaries