【摘要】 根据七芯铠装测井电缆的模型,利用时域有限差分法计算以模式7传输时信道的衰减特性。建立正交频分复用(OFDM)通信仿真系统模型,该系统可以有效地克服信道时延扩展和频率选择性衰落对数据传输的影响,现已广泛应用到测井设备的高速通信中。针对测井电缆信道的频率特性,在发送端引入一个预均衡器,适当地调整发射端各个子载波的发射功率,提高了接收端的信噪比,减小了误码率。用Matlab进行仿真,并验证了该结论。该预均衡器实现方便,应用前景广阔。更多还原

【Abstract】 According to seven-core armored logging cable model,the transmission characteristics of the manner 7 channel are calculated in time domain using finite difference method.The simulation model of the orthogonal frequency division multiplexing(OFDM)communication system is established.The OFDM communication system can effectively eliminate the impacts of the channel delay spread and frequency selective fading on the data transmission,and therefore it is widely applied in the high-speed communication of logging devices.According to the frequency characteristics of the logging cable channel,a pre-equalizer is added at the sender,and it can properly adjust the power of each subcarrier to improve the SNR of the receiving end and to reduce the BER.The conclusion is verified by simulation.This pre-equalizer can easily be implemented and therefore it has broad application prospects.更多还原