武汉大学 2012年攻读硕士学位研究生入学考试试题(科学学位) 回忆版(满分值 150分) file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image001.gif科目名称:信号与系统(C卷) 科目代码:934 注意:所有答题内容必须写在答题纸上,凡写在试题或草稿纸上的一律无效。 一、(20分)如下图所示框图 (1)求系统函数file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image003.gif (2)为使系统稳定,正实系数file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image005.gif、file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image007.gif满足何种约束条件 (3)在稳定条件下,画出H(s)极点分布图 (4)在稳定条件下,画出系统的单位冲击响应的波形图 file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image009.jpg 二、(20分)给出激励为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image011.giffile:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image013.gif时,全响应为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image015.gif,激励为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image017.gif,全响应为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image019.gif。此时的file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image015.gif和file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image019.gif都是给出具体表达式的。 (1)求单位样值响应; (2)求零输入响应; (3)如果激励为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image021.gif,file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image021.gif的表达式也给了出来,求零状态响应。 三、(15分)已知系统函数file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image023.gif,a>1 (1) 求H(z)的零、极点 (7分); (2)借助s—z平面的映射关系,利用H(s)的零、极点分布特性说明此系统具有全通性 (8分)。 四、(20分)已知某系统函数为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image025.gif,在下列三种收敛域下,哪种情况对应左边序列、右边序列、双边序列?并求出各对应序列。 (1)file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image027.gif (2)file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image029.gif (3)file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image031.gif 五、(20分)求下图输入输出方程。 file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image032.jpg 六、(20分) 已知某电路如下图所示,file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image034.gif,file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image036.gif,file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image038.gif,电路电容上的电压file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image040.gif为输出,file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image042.gif为输入。 (1)求单位冲击响应file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image044.gif; (2)欲使零输入响应file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image046.gif,电路初始状态file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image048.gif和file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image050.gif; (3)当输入激励file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image052.gif时,欲使全响应file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image054.gif,求电路初始状态file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image048.gif和file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image050.gif。 file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image057.jpg 七、(15分)判断系统是否为无失真系统,为什么? (1)输入为sint输出为cost时; (2)输入为sint+cos2t输出为sint-cos2t时; (3)当file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image059.gif时。 八、(20分)给出一个框图,输入为file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image061.gif,经过和file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image063.gif时域相乘,再通过一个滤波器file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image065.gif,求输出file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image067.gif。 file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/01/clip_image069.gif
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