中文摘要：

本文提出了一种新颖的超视距条件下信道的宽带信号同步测量技术。首先在发射端和接收端各利用一台基带信号发生器产生相同频率的宽带步进频率信号。然后,通过两台锁定于同一颗卫星的GPS时钟频率参考源,输出极高稳定度的10 MHz信号作为基带信号发生器的外参考源,使得宽带信号的相位保持一致。接下来,利用GPS时钟频率参考源产生的秒脉冲信号作为触发信号,保证基带信号发生器和矢量网络分析仪同步发射和接收信号。通过对宽带信号的频域响应进行逆傅里叶变换,间接获得了信道的时域脉冲响应。实验在相距几十km的海面利用蒸发波导作为传输信道。通过对信道的衰落特性多径时延分布情况的观测与分析,该方法可获得200 MHz带宽信号的频域响应,比相同条件下时域测量的信号带宽提高10倍,等效的时域脉冲宽度达到5 ns,实验结果验证了技术的有效性。

英文摘要：

A novel synchronous method is proposed for measuring wireless channel with the frequency domain response of a wideband signal at non-line-of-sight. Baseband signal generators at the transmission terminal and the reception terminal respectively are used to generate the wideband stepped-frequency signal of the same frequency. The two GPS clock frequency reference sources locked on the same satellite are used to generate the high-stability 10 MHz signal as the external reference source of the baseband signal generator, so that the initial phases of the wideband signals are basically the same. The pulse per second（PPS） signal generated by the GPS clock frequency reference source is used as trigger signal to ensure that the baseband signal generator and the vector network analyzer（VNA） can transmit and receive signals synchronously. To verify the measurement method, evaporation waveguide on the sea surface is used as propagation channel, which is tens of kilometers apart from each other. The delay-spread of the sea surface is measured, and the measurement method can obtain the frequency domain response of the signal whose band is 200 MHz and the equivalent pulse width reaches 5ns, which is improved 10 times compared with the time domain measurement. The experimental results show that the measurement method is effective.