周期性方波信号如下图所示,则下列叙述正确的是http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/f6e3744eb62c46678fbb8c123d71d22f.png
举一反三
- 周期信号f(t)如下图所示，其直流分量为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/bb02e5afe3fa474093913374442813ab.png
- 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
- 下图所示序列f(k)闭合表示式为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e3088842d7014311aa5241014415b8f3.bmp
- 信号f1(t)和f2(t)如下图所示，f(t)=f1(t)*f2(t)，则f(-1)等于http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/0749958f4da44655959aea343dbe4d9c.bmp
- 下列尺寸标注正确的是（ ） A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/79ed6f04ee2f415c917c9f280eccf07e.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/4677ac7155c849bebe9d2ffd7458f4c4.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/489ad68ff6294831bc43fa08990b59b7.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e829c514224942f1926c1823be08d3e7.png">