1长春理工大学光电工程学院, 吉林 长春 130022
2长春理工大学空地激光通信技术国防重点学科实验室, 吉林 长春 130022
为了研究矩形脉冲激光在大气中的传输特性,建立了脉冲信号在大气中传输的数学模型,并提出了一种信道补偿算法。在相距6.2 km的两栋高楼之间开展了100 MHz的矩形脉冲传输实验,并在FPGA编译软件上对信道补偿算法进行了验证。结果表明:脉冲信号经过大气信道后发生了畸变,大气信道在频域上表现为一个低通系统,抑制了大于430 MHz的高频信号。运用信道补偿算法后,脉冲畸变得到有效抑制,系统带宽得到拓宽,信号的信噪比提高了5倍左右;当光信噪比为10 dB时,误码率降低为10 -6。
In order to investigate the propagation characteristics of rectangular pulse laser in atmosphere,a mathematical model of pulse signal propagation in atmosphere is established and a compensation algorithm for channel is proposed. A propagation experiment of 100 MHz rectangular pulse is carried out between two buildings with a distance of 6.2 km, and the compensation algorithm for channel is verified by FPGA compliling software. The experimental results indicate that the pulse signal is distorted after passing through the atmospheric channel. The performance of atmospheric channel can be considered as a low-pass system in the frequency domain and signals with high frequency larger than 430 MHz are suppressed. With the channel compensation algorithm, the distortion of rectangular optical pulse is suppressed effectively, the system bandwidth is improved, and the signal noise ratio is increased by 5 times. The bit error rate decreases to about 10 -6 when the optical signal noise ratio is 10 dB.