离散时间LTI系统的单位脉冲响应 ，则该系统是 。https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/5aa5b5c9c18049a88e05da3af12a5245.png
举一反三
- 两个单位冲激响应分别为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/b1f29e9ad1e54df9970c1be374e67572.png"/>和<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/4c734b95e1024abfbc0741fb7c5455e2.png"/>的LTI系统并联构成的系统的单位冲激响应是<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/d7c571b4af814da7997bc653b0fbe308.png"/>。
- 下列方程所描述的系统中（ ）是线性时不变系统。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/5740348e23d246eebda0442284882d6d.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/87c5df9c28f54b398bbedc5da45e7a02.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/ece1036e5a3c410e8f8b3de147910c04.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/69fc98a558ce4f3eb743c68be74cf923.png"/>
- 信号通过单位冲激响应为的LTI系统，输出等于（ ） 。https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/f6cb0e4770dd46459497fe9b56a87710.png
- 两个单位冲激响应分别为，的LTI系统级联构成的系统，其总的单位冲激响应是。https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/7b8635bb2e444b109188d0e98b07eda0.png
- x(t)的频谱为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/5bcfe4175fcb4fabbdb5f40d00b5343e.png"/>，则<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/45b1670ebd6245ff99cc376a8048a645.png" />的频谱为（ ） A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/09bc7326832a4a1fba983e74c6d85d35.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/95fca346a74e4a6cbba601cd6d9e26bf.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/6bf6b83111ad45efac7eb9a37a245c68.png"/> D: 其余选项都不对