21秋西南大学1073 信号与系统在线作业
1073 信号与系统1.[单选题] 设系统函数<img width="120" height="24" style="width: 130px; height: 30px;" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/>，则冲激响应为( )
A.{11-2}
B.1
C.{111}
D.0
2.[单选题] 若数字滤波器在<img width="41" height="22" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/>两点处的幅值为（1，1），则该滤波器为（ ）
A.A.lp
B.bp
C.bs
D.hp
3.[单选题] 利用Matlab求取系统的冲激响应，调用的函数是（ ）
A.step
B.impulse
C.initial
D.lism
4.[单选题] 已知<img width="126" height="38" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/>，设抽样频率为100Hz，则所得序列的数字频率为 ( )
A.0.4pi
B.0.3pi
C.0.2pi
D.0.1pi
5.[单选题] 已知周期序列<img width="64" height="38" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/>，其周期为( )
A.9
B.6
C.12
D.3
6.[单选题] 共轭对称的信号，其幅值与相位分别为（ ）
A.C.偶、偶函数
B.奇、偶函数
C.偶、奇函数
D.奇、奇函数
7.[单选题] <img width="146" height="32" src="data:image/png;base64,R0lGODlhkgAgAHcAMSH+GlNvZnR3YXJlOiBNaWNyb3NvZnQgT2ZmaWNlACH5BAEAAAAALAMABwCIABQAhQAAAAAAAAAAHR0AAB0AHQAAMx0AMgAdMgAcSB0dSAAzWh0zWh1GbDMAADIAHTQdHTIAMjNbgEgcAEgdHVozAFozHV1dM1tISEhIW0ZGbkhbbkhZf0huf11/f1luf2xGHW5GM25GRn9ZSH9/XX9uSG5/WWaIiIBbM4iIZgECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwb/QIBwSJQEGIBAQEFsOp/QqHRKrVqvVtAwMIxgv+CweCylcJ0nsnrNbjs1AKRQKxR03VAmPk8eFPYARggADUuATYNXElFGAXZOiVCLh01ylFUJVRhNHE+dJAOWQplUnVJel6lCFFUfTnpWrFWwTxBrtGqNTY5ESn9WhWdDBk8Uv1PBqMNPAQUWQslgsmyTAI8USB+/C4iYTtVDA3WQTqRN4IF6DUPmYLhiaU4EQ+ugsK5U+OfdQuj6RKKGoLM0YUhAJ0oSGgJA4Z2YSEJOPGoyYCFEKBSUCbRETMrFaecsRYrHkIxDMCeOhRNIEQBJKba+DQEJoOOQl1OqTQN1MIpCgiV6aJJZdy6RTYMAHIiJKeTYPCdKiZxkGkfIgQdDTlrRCiYYkUICPlVcCEAjsye0gl0kouwDWalDQJ1pcACAW65T8KqqCabgl6NQ/KbSG+hIkrdqcFJBZ0XxPlX/qgjbi/GQUEqWGiXE5Ziy589T6EiYaBa06TaMGQUYVIjw6ddWggAAOw==" v:shapes="_x0000_i1025"/>（ ）
A.B.-1
B.0
C.2
D.1
8.[单选题] <img width="84" height="21" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/>( ）
A.f'(t)
B.１
C.f(0)
D.f(t)
9.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=00quiLk3cf58b9c_14ffaafdef7_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.因果稳定
B.因果不稳定
C.非因果稳定
D.非因果不稳定
10.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=00quiLk3cf58b9c_14ffaabe3af_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.中心频率点为ω0，幅值为原信号频谱幅值的一半
B.中心频率点为±ω0，幅值为原信号频谱幅值的一半
C.中心频率点为ω0，幅值为原信号频谱的幅值
D.中心频率点为±ω0，幅值为原信号频谱的幅值
11.[单选题] 对离散系统系统频率响应仿真，调用的函数是（ ）。
A.step
B.impulse
C.freqs
D.freqz
12.[单选题] 下列系统中，属于线性时不变系统的是（ ）。
A.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff7934397_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
B.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff793bdc7_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
C.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff79450e0_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
D.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff794e34c_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
13.[单选题] 关于稳定性的描述，下列叙述中错误的是（ ）。
A.稳定的充要条件是有界输入产生有界输出，简称BIBO
B.线性时不变系统的稳定性理论上与输入信号无关
C.稳定性指的是系统克服扰动恢复到平衡态的能力
D.冲激响应可以表征系统的稳定性
14.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff78a74b3_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff78be193_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
B.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff78c554a_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
C.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff78cde54_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
D.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff78d59ea_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
15.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff786db80_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.2
B.4
C.-2
D.-4
16.[单选题] 关于信号的分解，下列叙述正确的是（ ）
A.傅里叶级数是一致性意义下的正交分解
B.任意普通信号可分解为冲激函数的叠加，可用卷积形式来描述
C.信号能分解为实分量和虚部分量，故可对信号进行滤波
D.由于信号的可分解性，故在时域中可用冲激响应来表征系统
17.[单选题] 关于三个变换之间的关系，下列叙述错误的是（ ）。
A.若原信号收敛，虚轴上的拉氏变换就是傅里叶变换
B.s域的左半平面映射到z域的单位圆内部
C.从s域到z域的映射是单值映射
D.s域的右半平面映射到z域的单位圆外部
18.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77c8205_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77da1ae_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
B.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77edcbe_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
C.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77f63d0_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
D.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77fe1f9_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
19.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=00quiLk3cf58b9c_14ff777c79c_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff777df5f_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
B.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff7797a42_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
C.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77a2b34_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
D.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff77adf50_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2'/>
20.[单选题] 下列系统中，不属于线性系统的是（ ）。
A.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff560854f_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT'/>
B.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff561240d_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT'/>
C.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff561a3d5_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT'/>
D.<img src='http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff5621e1d_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT'/>
21.[单选题] 下列叙述正确的是（ ）。
A.各种离散信号都是数字信号
B.数字信号的幅度只能取0或1
C.将模拟信号采样直接可得数字信号
D.采样信号经保持、滤波后可得模拟信号
22.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff5150b13_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT"/>
A.0
B.1
C.无穷大
D.不存在
23.[单选题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff5123220_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT"/>
A.LP
B.HP
C.BP
D.BS
24.[单选题] 设系统输入输出关系为y(t)=x(t)cos(t) ，则系统为（ ）。
A.因果稳定
B.非因果稳定
C.因果不稳定
D.非因果不稳定
25.[单选题] 已知序列<img width="107" height="45" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/>，则<img width="53" height="24" src="data:image/png;base64,R0lGODlhNQAYAHcAMSH+GlNvZnR3YXJlOiBNaWNyb3NvZnQgT2ZmaWNlACH5BAEAAAAALAIAAwAxABEAhAAAAAAAAAAAHQAAFx0AHQAAMwAcSAAzWh1GbCgZADMAADIAMjIyADMzWzNbgEgcAEgdHUceM1ozAEhuf11/f2xGHX9/XX9uSG6AbmaIiIBbM4iIZgECAwECAwECAwECAwWdICCOQCCIDqmubOuSjRggb23feK5XQT/2g0TPIHoQVUYRL3DUaQSTkWJ0kDJViiupqXuMIiMvqcJVcsm6LQCiqqpX5XLOhHSbV+h3GjBd2UVyAHEqPYU+KwsMfwBiI3ljZ4E1CwAVBX4qgYM6lCIEdZB4myIShoV2lyQ0JIuamThZMyKxJ0UktLc9tZWSeyKLOL17D8A3wntDc1o1IQA7" v:shapes="_x0000_i1026"/>（ ）
A.12
B.9
C.3
D.6
26.[单选题] 设<img width="25" height="23" src="data:image/png;base64,R0lGODlhGQAXAHcAMSH+GlNvZnR3YXJlOiBNaWNyb3NvZnQgT2ZmaWNlACH5BAEAAAAALAIABAAVAA4AhQAAAAAAAB0AHQAdMh0AMgAAMwAcSB0dSAAzWh0zWh1GbDIAHTMAACwAMjIAMjNdXTNbgEgcAEgdHVozHVozAFtIHUhIW0huW0huf11/f2xGHX9ZSH9uSH9/XWaIiIBbM4iIZgECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwECAwZgQIBwSAQgiJOiUvhZRpbFA3QBHUKKV+FRGDAIGYMGkREIZAlECcABaFYBT2Jh6CUqiJG7kDPUFClFcUMCdERseFkAV1cPRUcYQ2wUAXoBR4BCGpZvRWhQkG91nFAJWENBADs=" v:shapes="_x0000_i1025"/>是带限信号，<img width="43" height="24" src="data:image/png;base64,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" v:shapes="_x0000_i1026"/> rad/s，则对<img width="44" height="30" src="data:image/png;base64,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" v:shapes="_x0000_i1027"/>进行均匀采样的最大间隔为 ( )
A.0.2s
B.0.5s
C.0.1s
D.0.3s
27.[单选题] <img width="68" height="21" src="data:image/png;base64,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" v:shapes="_x0000_i1025"/> ( )
A.D.x(t)
B.-x(t)
C.x(0)
D.-x(0)
28.[判断题] 当周期趋于无穷大时，周期信号的频谱就由离散谱变为了连续谱。
A.正确
B.错误
29.[判断题] 离散因果LTI系统稳定的充要条件是所有极点的模值小于1。
A.正确
B.错误
30.[判断题] 竖式乘法可用来求有限长序列的卷积和。
A.正确
B.错误
31.[判断题] 正弦信号是功率信号。
A.正确
B.错误
32.[判断题] 数字域中，带限信号的意思是指最高频率小于等于2π。
A.正确
B.错误
33.[判断题] 若群延迟为常数，则数字滤滤器具有线性相位。
A.正确
B.错误
34.[判断题] 周期信号的单边谱与双边谱中，直流分量的幅值相同。
A.正确
B.错误
35.[判断题] 一个共轭对称的实信号，必为偶函数。
A.正确
B.错误
36.[判断题] 信号间断点处的微分，存在有冲激函数。
A.正确
B.错误
37.[判断题] 离散因果LTI系统，特征根模值小于1时，响应分量收敛。
A.正确
B.错误
38.[判断题] 可选择频谱包络线第一次的过零点作为信号的带宽。
A.正确
B.错误
39.[判断题] 利用几何作图的方法，可以由零极点的分布绘制频率响应曲线。
A.正确
B.错误
40.[判断题] 原信号收敛时，虚轴上的拉氏变换就是信号的傅里叶变换。
A.正确
B.错误
41.[判断题] 对于DFS，时域与频域的周期都是N。
A.正确
B.错误
42.[判断题] 周期信号谐波分量的频率，都是基频的整数倍。
A.正确
B.错误
43.[判断题] 冲激信号是偶函数。
A.正确
B.错误
44.[判断题] 抽取与内插意味着抽样率的转换。
A.正确
B.错误
45.[判断题] 系统函数可由比值形式定义，故与输入信号的形式有关。
A.正确
B.错误
46.[判断题] 离散系统原点处的零极点，不影响频率特性幅值，只影响相位。
A.正确
B.错误
47.[判断题] 线性相位，指的是系统的相频特性与频率成正比。
A.正确
B.错误
48.[判断题] 系统为因果系统的充要条件是冲激响应是因果的信号。
A.正确
B.错误
49.[判断题] 任意普通信号可分解为冲激函数的叠加，可用卷积形式来描述。
A.正确
B.错误
50.[判断题] 连续时间LTI系统稳定的充要条件是所有极点的实部小于等于零。
A.正确
B.错误
51.[判断题] 冲激响应只适用于LTI系统。
A.正确
B.错误
52.[判断题] 频率响应反映了对输入频谱的加权作用。
A.正确
B.错误
53.[判断题] 非周期序列的频谱，是周期连续的频谱。
A.正确
B.错误
54.[判断题] 实际周期信号的频谱具有离散谐波性与收敛性。
A.正确
B.错误
55.[判断题] 无论连续还是离散的LTI系统，响应都可以分解为零输入与零状态响应之和。
A.正确
B.错误
56.[判断题] 任意序列可看作单位脉冲序列移位加权的和。
A.正确
B.错误
57.[判断题] 因果信号是稳定的信号。
A.正确
B.错误
58.[判断题] 本课程中，信号一般指电信号。
A.正确
B.错误
59.[问答题] 周期信号的单边谱与双边谱的关系是什么？
A.
60.[问答题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLk3cf58b9c_14ff7e18110_OUL&rc=oVdA47x%2B4VctsHYg3UjY2b7YYwf6GaE2"/>
A.
61.[问答题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff57bb7c2_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT"/>
A.
62.[问答题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff537317d_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT"/>
A.
63.[问答题] <img src="http://fs.eduwest.com/filesys/image.jsp?fc=10quiLi3cf58b9c_14ff531227e_OUL&rc=oVdA47x%2B4VctsHYg3UjY2cV%2FVU6vsuPT"/>
A.
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