已知Z变换Z<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/94487389db974f98b2d38b947ec20d83.png" >，收敛域<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/56b4868c286b4b48a8cec67f9f766670.png" >，则逆变换x（n）为()。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/547656863c8b459da97c366d9321ef13.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/d3572493bf964e2d92fde49d59b632af.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c4aacba69e0445b0ad4db797b3c86d53.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/b9af7d9dccb3446595a3a587492eb92a.png" >

理想不失真传输系统的传输函数H（jω）是()。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c53311dbea924826a56276a9472741b1.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4f089e5988004320950aab7179fb9c28.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/2245b8eb25204e8e966be03821487380.png" >（<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/14618be7a9474fa09351a25e922eb774.png" >为常数） D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/9cba3ab48faa4d8980c79f62bb1f3da4.png" ><img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/64f67bce595243aaa13ded6089b431b1.png" >

下列系统中线性时不变系统是（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4b45f35cbb8b49eea328e0f1af3a3101.png" >（<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/3f1f37fe4ba54c4fb69d1be115a88f2d.png" >为常数） B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/481b4d4b98e24b94a2eaa9ec011e0186.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/f0f925fadec648b4b7c35161be6f3a3d.png" >（<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c10b602726304747bf5fe38a760da1ae.png" >为常数） D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/62c5dee47e9045cca90a53856dc04845.png" >

已知信号<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/82c317e53c6941b59567bc236a6ec9ba.png" >，则奈奎斯特取样频率fs为()。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/7f3cd88d635b4fe0871233447ea5494b.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/53752d34e4c64504bc111e280262e228.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/50d5151b1d3f406185372b2ac9f19f93.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/ad47ea06d5aa4270a8e0089425f0bf6d.png" >

假定<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/71458e4f29a24928a4ad4d36e72ec6b9.png" >，以下关于z变换的性质描述，正确的是：（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/545e8d644963417494a94eec7ae1bf50.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/04445d84fa3443968231a11a580079e2.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/5599b26833e546dfa3ab9c1c656c6581.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/fcc7d5135a714189b801863712e6b7f5.png" >