论文部分内容阅读
在甚高频波段(VHF)和超高频波段(UHF)移动通讯中,下列因素决定两个通讯站间的有效通讯距离。频率频率影响收发天线间的传播损耗、传输线损耗、接收机噪声系数、环境噪声和干扰、移动和失谐效应。提高工作频率,损耗增加,噪声系数变大,移动和失谐效应也更严重,然而却降低环境噪声和干扰。
In Vhf and UHF mobile communications, the following factors determine the effective communication distance between two communication stations. Frequency The frequency affects the propagation loss, transmission line loss, receiver noise figure, ambient noise and interference, movement and detuning effects between transmit and receive antennas. Increase the working frequency, loss increases, the noise figure becomes larger, the movement and detuning effect is more serious, however, it reduces the environmental noise and interference.