为了解决宽带航空数据链频率资源匮乏的问题,L频段数字航空通信系统(L-DACS,L-band digital aerona-utical communications system)将以内嵌的方式部署在航空无线电导航L频段测距仪(DME,distance measure equipment)波道间,因此,不可避免产生测距仪信号干扰L-DACS系统接收机的问题.为了定量描述DME/N(distance measure equipment/normal)与DME/P(distance measure equipment/precision)信号带外泄露对L-DACS系统接收机的影响,首先建立了DME/N与DME/P信号数学模型,然后理论推导出DME/N与DME/P信号的功率谱密度表达式,以此为基础研究了DME/N与DME/P信号带外泄露对邻道部署的L-DACS系统接收机的影响,最后通过计算机仿真验证了理论分析结果的正确性.研究表明:DME信号带外泄露对L-DACS系统的影响主要表现在第一邻道,DME/P信号在第一邻道内泄露功率比DME/N信号泄露功率高约10 dB.
To solve the problem of spectrum resource scarcity in aeronautical data link,L-band digital aeronautical communi-cations system(L-DACS)will be deployed as an inlay system in the spectral gaps between channels of the distance measuring equipment(DME).Therefore,it's unavoidable that the DME signal has a severe influence on the perfor-mance of L-DACS system receiver.To analyze the influence of out-of-band leakage of DME/N(distance measure equipment/normal)and DME/P(distance measure equipment/precision)signal on L-DACS system receiver,the mathematical models of DME/N and DME/P signal are established,firstly.Then,the expressions of power spectral density of DME/N and DME/P signal are theoretically derived.Based on these expressions,the effect of out-of-band leakage of DME/N and DME/P signal on L-DACS receiver,which is deployed in adjacent channel,are researched.Finally,the correctness of the theoretical analysis results is verified through computer simulation.The results show that the impact of out-of-band leakage of DME signal on L-DACS system is mainly manifested in the first adjacent channel,and the leakage power of DME/P signal in the first adjacent channel is 10 dB higher than that of DME/N signal.