若连续非周期信号
的频谱函数为
，则两者具有一一对应关系。（ ）
的频谱函数为，则两者具有一一对应关系。（ ）
举一反三
- 已知 f (t)，为求<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/1fb776d0006a4eb2b93e07afcad58896.png" />则下列运算正确的是（其中<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/ada31d4207fe47d4908574b0a478486b.png" />， a 为正数）（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/fb0a09472a6b4408b3e833c2568308db.png" />左移<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/ada31d4207fe47d4908574b0a478486b.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/fb0a09472a6b4408b3e833c2568308db.png" />右移 C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/06dbb96ce1044280b13167a33033e4c6.png" />左移<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/ada31d4207fe47d4908574b0a478486b.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/06dbb96ce1044280b13167a33033e4c6.png" />右移
- 已知信号<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/dd73dc4df2f24b0780af6a97fdf8a562.png" />的奈奎斯特角频率为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/a43212a9536a46ac8a20c6dc7d78906d.png" />，则信号<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/1821f6e23ad74b4ca7d8fb212ee4dada.png" />的奈奎斯特角频率为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/9eb48130d0e24c1c8234e1de4c730c0f.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/db0c7b373ae04e0599630a5086233c04.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/353ea3d067db4076977d456717aa82d2.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/6d550ebc083244648d78d5b2c334dfce.png" />
- 已知信号<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/4ec9ab73e5b14287a9d5d05ffec6c92f.png" />的最高频率分量为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/cfd4341db5d343b8bccc69ec8104cdeb.png" /> Hz，若抽样频率<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/6e1e4607f8c5465bb3fffcba402cb876.png" />，则抽样后信号的频谱一定混叠。（ ）
- 已知<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/0b6bd03a30394de5866eb04046000d07.png" />，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/aced01bc1bc24d49a068c754294b44e3.png" />，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/8872a86bb2a9457dace1176d21809909.png" />，用拉普拉斯变换法解微分方程<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/8ae2532227474de1bbdb5326fb2a05ec.png" />的零输入响应和零状态响应为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/5dac342ceb7141799376d81642c7bd17.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/c6491375b34b48ea9e1aa1e3cfda2c51.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/12c8d30af4244ab89d52eb7203d6d3a7.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/72758b4605f24d69a235afc727a0b877.png" />
- 下列分布函数性质的叙述中错误的是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/aa7be662728549808e1e31a941f40586.png" />是右连续函数，即<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/3d2dd341bbb34bc49c6c16a0648e73a0.png" />; B: 对任意一个实数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/6af90c1b0d1a4a2e9f52db02fba49eb3.png" />，都有<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/76a52406d5984c29b26b56770cd45589.png" />. C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/700eb5d94c754071b3fabc46105a97e5.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/15b2abeddbab4e798304b38ed7d0a073.png" />; D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/25cc87b8d99c4475861371e994a4a857.png" />是<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/b62c2e7b67af45a28d3b1d079dd4ffd0.png" />单调非减函数;