已知信号
的最高频率分量为
Hz，若抽样频率
，则抽样后信号的频谱一定混叠。（ ）
的最高频率分量为 Hz，若抽样频率，则抽样后信号的频谱一定混叠。（ ）
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<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" />
- 已知某系统的数学模型为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/36eb028cda9447468911e236a321722e.png" />，那么系统的沖激响应<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/2a6ea359e85c408fbece93c2e81f6076.png" />为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/2c5c40b2c9f84205812addf9df60664b.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/d1350a891d364096858a5f83a7415ece.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/e1352972cbd24aacb663ce6ef7fc95fc.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/1c91057ec86848a1b761ccb26b3ed883.png" />
- 求序列<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/5131160157fe4bc7bd53878104ffd1cd.png" />的DTFT为（ ） A: 不存在 B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/e521d6f23d234b38b3ad34622a74b1b2.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/fbec0bedcb3c47a8825ec337b818764f.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202101/5fc107dac73e4c00afcf8f1701f80a47.png" />