排序方式: 共有3条查询结果,搜索用时 15 毫秒
1
1.
A communication system based on an ultraviolet(UV) laser at 266 nm is presented to improve the communication distance. The pulse frequency-shift keying(FSK) modulation scheme is studied and improved in order to reduce the bit error rate(BER), and is put into practice on a field programmable gate array(FPGA). The mathematical models of the modulation and demodulation are established. A test platform is set up to measure the energy density and pulse response under different distances and receiver elevation angles. It is shown that the omnibearing communication can be realized, and the bit rate is limited to 12.5 Mbit/s. The BER is estimated to be less than 10-7 at distance of 300 m in line-of-sight(LOS) communication model and to be less than 10-6 at distance of 80 m in non-line-of-sight(NLOS) communication model. 相似文献
2.
3.
为了扩展自由空间光通信的应用领域,设计了一套稳定性好、实用性较强的逆向调制光通信系统。采用一种基于声光调制器、逆向光链路等核心元件的实验方法,利用现场可编程门阵列发出晶体管-晶体管逻辑门电平对声光调制器进行控制,采用二进制频移键控与二进制脉宽调制调制相结合的四进制调制方法,同时使用冗余校验置换、改进的汉明码等加密纠错方式,实现了室内逆向调制激光通信。结果表明,该通信系统的串口通信速率可达115.2kbit/s、高频载波达1MHz、且保密性良好、误比特率低于10-6,同时证明了激光外调制逆向通信系统载波最高可达到5MHz左右。 相似文献
1