已知信号的波形如下图所示，则的表达式为（）。http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/74c2f63c12344e7eaf6ee42fcc6d1cce.png
举一反三
- 已知信号f(t)的波形如下图所示，则f(6-2t)的波形图为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/414e4bc7b0b44f6e8f660e9dd1189014.bmp
- <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" />
- 设<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/caa2009d65b9414e9eee2f311038ed51.png"/> 为系统输入，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/af57e24c7bb247e29a81996211b39e9d.png"/>为系统输出，则下列关系式中为线性时不变系统的是（ ）。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/6d8d3ed4bbb5472d8ad95cf86ff40033.png"/> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/553b7fd10b744a38859127a91414813b.png"/> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/e59a6933e2c647d4b5c12b2ebb0a0ff6.png"/> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/4835c010dc244facb01784095e9bd080.png"/>
- 已知系统的差分方程为：<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/4d2011df82b5487b90c89c82392b7635.png" />初始状态<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/69fdc69872fc4526b3406d4e545b5423.png" />输入信号为<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/75e7d55edcb246e396b63e810f4b0c5f.png" />求系统的零输入响应。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/f3d4c0dc2e044821ad7f2fa06ae922de.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/5b82c0acece14a83ad58bc9d533a1885.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/06178caff4d54505b3a9dbfcd3f413ea.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/0b7c106121734430927a095f909fe51f.png" />
- 如下图所示，卷积的结果是http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/8e68466fb1f040f59d0906b7e417f5b6.png