信号 如图所示，求其频谱。http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/e7cf021b113341e4bb5ee98d7d12e0f2.png
举一反三
- 信号波形如图所示，求其三角形式傅里叶级数。http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/762886bac78f4048a5f95e16046ee6ac.png
- <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/2205d9f03e724a04b34f2f1045309079.png" />的幅频响应是，幅频响应是。 A: 1，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/760d7fcc2f264ed1b10fb836cb48f565.png" /> B: -1，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/21f685d2962e4b6993bfcaa513bdbf68.png" /> C: 2，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/57267e995f86426899ce3cc0177a2343.png" /> D: 1，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/ea8ba62853a94a15a5620c5165e3594a.png" />
- 某离散时间系统的系统框图如图所示，其中x表示输入信号，Y表示输出信号，系统的差分方程可以表示为？<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/f17b1754961a482eb540b5229ed1d3b7.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/0769d057673d4151b1f0b41af2ffe512.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/3538ab9355d34bdb854faaddbd64abd6.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/62652baf39794e328f736a5e1dc4a701.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201904/90ff953c2cb044b8a0662afaf143d417.png" />
- LTI离散系统的差分方程为<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/eb2e05fecafa414e98c3ffaf0b435e82.png" />，当激励<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/f6bdc410c9fd42b8b8dd675197919ceb.png" />时，求零状态响应<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/12bfebbed6b14e298e09c4cb1940677b.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/69fc6db7834143a292ce24d4829a06e6.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/f7af4326d64c44669cd0f0d4c7b23eb1.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/f929cab698bd4309a4649201e7f5604c.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/81108c43b5f2457291e3723cc96280e1.png" />
- 已知，求其逆变换为：？http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/ae9f3d1643584e7e93c28c20a1a66ed8.png