单选题无线列调机车电台的天线为()天线,在机车顶部安装。A 定向B 全向C 八木...
Monday, December 5, 2022
Tuesday, July 25, 2023
在模拟微波通信系统中,常用的调制方式是调频;在数字微波通信系统中,常用()方式。...
Wednesday, September 14, 2022
一发射机发射功率为10W,天线增益10dB,馈线损耗5dB,则有效辐射功率为()。...
Thursday, September 22, 2022
Thursday, September 22, 2022
Saturday, September 17, 2022
判断题为提高无线列调移动设备的接收效果,所选用的天线是定向天线。A 对B 错...
Friday, August 4, 2023
Thursday, September 22, 2022
Friday, August 4, 2023
Wednesday, November 22, 2023
Thursday, September 22, 2022
填空题无线通信技术中的均衡是指对信道特性的均衡,即接收端的均衡器产生与信道相反的特性,用来抵消信道的时变多径传播特性引起的()干扰。...
Saturday, November 11, 2023
Friday, May 5, 2023
将天线在某一频率上所测得的水平面或垂直面的归一化方向性函数绘制在极坐标或直角坐标上所得的图形分别称为该天线的水平面或垂直...
Wednesday, September 14, 2022
Friday, September 16, 2022
中国移动力推()方案,将移动通信网的漫游功能和无线局域网结合,提高用户无线上网的覆盖范围。...
Monday, August 8, 2022
某雷达载波频率为2900MHz,可以称它为()波段雷达。...
Thursday, September 22, 2022
光纤直放站系统光纤连接拓扑分为()和(),西延线光纤直放站系统的光纤连接拓扑是()。...
Thursday, September 22, 2022
数字微波中继通信对天馈线系统的匹配要求很高,驻波系数应低于()。...
Saturday, September 17, 2022
Thursday, September 22, 2022