某调角信号为，其最大频偏为（ ）。http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/40edb3ddac0a4e85a273eb618f034b56.png
举一反三
- 某单音调频信号，则调频指数为（ ）。http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/919bd25db19b4bb1a21ef51d53da20bb.png
- 直径为d的圆截面钢杆受轴向拉力作用，已知其纵向线应变为<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/767e7380667c4d688dc6c10aaf9ef9ca.png" />，弹性模量为E，给出杆轴力的四种答案，问哪一种是正确的？ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/8f37f5bc2dc94791b84f000092e493b3.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/073a4958352c4951b6171383bc4ca238.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/85f164582f934227b4bbb5ee0a7267dc.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/95e66fa0756f4ffd8c0ae368c0c88564.png" />
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/7fd9024d3a004d5990381d58527fa633.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/c12b9cef296b443ca06cd2980c89d3f7.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201801/1290f16d3bff44ee8c99d548a838f423.png