2022年电子科技大学学年第学期信号与系统期末考试A卷 .pdf

《2022年电子科技大学学年第学期信号与系统期末考试A卷 .pdf》由会员分享，可在线阅读，更多相关《2022年电子科技大学学年第学期信号与系统期末考试A卷 .pdf（5页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、学院姓名学号任课老师考场教室 _选课号 /座位号密封线以内答题无效第 1 页 共 5 页电子科技大学2014-2015 学年第1 学期期末考试A 卷课程名称：信号与系统考试形式：一页纸开卷考试日期：20 15 年 1 月15 日 考试时长：120 分钟课程成绩构成：平时10 %， 半期考试20 %， 实验10 %， 期末60 % 本试卷试题由二部分构成，共5 页。题号一二合计得分1 2 3 4 一、选择填空题（共30 分，共 6 问，每问 5 分）1. Consider two signals 1x tand 2xt , as shown in Figure 1. The Fourier tr

2、ansform of 1x tis 1Xj. Then the Fourier transform of2xt should be （）. (a) 31jXje(b) 31jXje(c) 31jXje(d) 31jXjeFigure 1 The waveforms of 1xtand 2xt2. The convolution sum cos() 2nnu n( ). (a) 123nu n(b) 1cos3n(c) 1cos3n u n(d) not existed 3. Consider a stable discrete-time system, whose system functio

3、n H zis a rational function and has only two poles ：121/ 2,2zz. The positions of zeros are unknown. The impulse response h nof the system must be ( ). (a) finite duration (b) right-sided (c) left-sided (d) two sided 4.The relation between the input and the output of a causal continuous-time LTI syst

4、em is described by the differential equation 2232d y tdy ty tx tdtdt. The system is （）. (a) Low-pass filter (b) Band-pass filter (c) High-pass filter (d) Band-stop filter 5.The Fourier transform of the signal x tis shown in Figure 2.The signal x tmay be (a) real and even (b) real and odd (c) pure im

5、aginary and odd (d) pure imaginary and even 6. The Laplace Transform of )1()(ttutfis )(sF（）.(a) )1(12ses，Re 0s(b) )(sses12，Re 0s(c) )1(12ses，Re 0s(d) )(sses12，Re 0s得 分t1x t0121t2xt01211131101122XjFigure 2名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 1 页，共 5 页 - - -

6、- - - - - - 学院姓名学号任课老师考场教室 _选课号 /座位号密封线以内答题无效第 2 页 共 5 页二、计算题（共 70分）1. （ 15 points ） Suppose 1xtand 2xtare both band-limited signals, where 10 for 200Xj, 20 for 300Xj.Impulse-train sampling is performed on 1222/ 33y txtxtto obtain pnyty nTtnT, as shown in Figure 3 where /,0,TjTTH.Deduce the value of

7、 Mso that 0)( jYfor M.Specify the range of values for the sampling period T which ensures that ryt =ty. Figure 3 得 分typtyryt名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 2 页，共 5 页 - - - - - - - - - 学院姓名学号任课老师考场教室 _选课号 /座位号密封线以内答题无效第 3 页 共 5 页2.( 18 points ) Consider

8、 an LTI system with unit impulse response sin(1.5 (1)sin(0.5(1)(1)tth tt.The input signal cos()x tut，where 1,00,0uis the unit step function. (a) Sketchtx. (b) Determine the magnitude and phase response of this system. (c) Determine the output y t.得 分名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - -

9、 - - - 名师精心整理 - - - - - - - 第 3 页，共 5 页 - - - - - - - - - 学院姓名学号任课老师考场教室 _选课号 /座位号密封线以内答题无效第 4 页 共 5 页3（17 分）A causal continuous-time LTI system is given in Figure 4. (a)Determine the range of the constant K to ensure that the system is stable. (b)If K=2, determine the unit step responsets. 得 分1/S 3

10、 x ty t1/S 2 K Figure 4 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 4 页，共 5 页 - - - - - - - - - 学院姓名学号任课老师考场教室 _选课号 /座位号密封线以内答题无效第 5 页 共 5 页4（20 分）Suppose that we are given the following information about a causal discrete-time LTI system: （1）If the input is x nu

11、n ，then the output is 1/ 22 1/ 3nny nau nu n. （2）The value of the unit impulse response at n=0 is 10h. Solve the following problems ：(a) Determine the system function H z ，and indicate its ROC. (b) Draw a block diagram representation of this system. (c) Determine the unit impulse response nh. (d) Suppose ng nh n . Determine the range of real number so that g nis the unit impulse response of a stable system. 得 分名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 5 页，共 5 页 - - - - - - - - -