信号与系统signal and system英文版往年考试题1.docVIP

Test （Chapter 1,2,3,4） 参考答案 I. Blank filling (Total scores 60, each scores 5. ) 1、 （70％） 2、 （96％） 3、 （92％） 4、Piecewise function can be comprised by rectangular window functions(可以用矩形窗函数构造分段函数). Consider a signal，the even component of is ＝ ，the odd component of is ＝ （46％） （92％） 5、Consider a signal ，and ，so 。 (Express your answer by rectangular window function like I.4) 先做微分 （76％） 6、Necessary and sufficient conditions for stability of the system is its impulse response should beint(f(x),-inf,inf)＝】 （37％） 7、consider a signal ，则 (Express your answer by rectangular window function like I.4) （87％） 8、Known Fourier transform of f(t) is ，so the Fourier transform of is。（71％） 9、The Fourier transform of is （83％） 10、A system S with input and output related by is time invariant while = . Constant（6％） 11、, then of is 2T（73％） II. Single choice(Total scores 24, each scores 6. ) 1.The equivalent expression of is ( D ) A： B： C： D： 2. Refer to the Fourier transform of , to determine when the Fourier transform of is , then is ( B ) A： B： C： D： 3.The input e(t) and output r(t) of a continuous system is regulated by r(t)=e(t+2), then the system is ( D ) A：causal, time-variant, linear, stable B：causal, time-invariant, nonlinear, unstable C：non-causal, time-variant, linear, stable D：non-causal, time-invariant, linear, stable 4.The input f(t) and output r(t) of a system is governed by , then the system is ( B ) A: Linear and time-invariant system B: Linear and time-variant system C: Nonlinear and time-invariant system D: Nonlinear and time-variant system III. True or False. (Total score 16, each scores 2.) 1.If system input is, then the system is linear. T 2.If (for any n), and k is a known constant, then the LTI system with unit impulse response h[n] is stable. F 3.The Fourier transform of real even signal is also a real even function. T 4.For any system, the impulse response completely describes its