By introducing orthogonal frequency division multiplexing （OFDM） technology, a visible light communication （VLC） system using a 5~5 white LED array is studied in this paper. The OFDM transmitter and receiver are m...By introducing orthogonal frequency division multiplexing （OFDM） technology, a visible light communication （VLC） system using a 5~5 white LED array is studied in this paper. The OFDM transmitter and receiver are modeled through MATLAB/Simulink tool. The electrical-optical-electrical （EOE） response of the VLC channel, which is also the re- sponse of the detector, is derived based on Lambert＇s lighting model. Then the modeling on the overall OFDM/VLC system is established by combining the above three models together. The effects of the factors which include the digital modulation, Reed-Solomon （RS） coding, pilot form, pilot ratio （PR） and communication distance on the bit error rate （BER） of the system are discussed. The results show that through the use of RS coding, block pilot, quad- rate phase shift keying （QPSK） modulation and a suitable pilot ratio about 1/3, under the communication rate about 550 kbit/s, the BER can be dropped to below 10^-5, and the communication distance can reach 0.9 m.展开更多
为适用CDMA各类收发机的射频本振的应用要求,研制了一种低杂散低相噪高分辨率的P波段频率合成器。利用DDS输出信号具有高分辨率和PLL具有窄带跟踪滤波特性,通过有效的频率规划和参数配置,规避了DDS由于相位截断近端杂散无法消除的缺陷,...为适用CDMA各类收发机的射频本振的应用要求,研制了一种低杂散低相噪高分辨率的P波段频率合成器。利用DDS输出信号具有高分辨率和PLL具有窄带跟踪滤波特性,通过有效的频率规划和参数配置,规避了DDS由于相位截断近端杂散无法消除的缺陷,有效抑制了DDS中DAC非线性和幅度量化误差引起的宽带杂散。通过仿真分析了方案的可行性,设计了样品并进行了测试。结果显示,所设计的频率合成器输出频率范围为755 MHz^765 MHz,频率分辨率为100.5 k Hz,杂散优于-71 d Bc,相位噪声优于-105 d Bc/Hz@1 k Hz。展开更多
卫星相干光通信在国外已经接近工程应用阶段,主流的传输接收方式为BPSK调制/零差探测,接收端用光锁相环(OPLL)进行载波恢复。但即使在今天,光锁相环的实现依然有难度,而且存在捕获时间过长等现象。文中借鉴了现在的研究热点技术——光...卫星相干光通信在国外已经接近工程应用阶段,主流的传输接收方式为BPSK调制/零差探测,接收端用光锁相环(OPLL)进行载波恢复。但即使在今天,光锁相环的实现依然有难度,而且存在捕获时间过长等现象。文中借鉴了现在的研究热点技术——光纤通信中的频偏估计、载波相位恢复技术,针对星间激光通信中存在GHz量级大多普勒频移的工程背景,提出了一种基于DSP的频偏开环补偿算法。从理论上分析了该算法的原理,重点研究了激光器噪声和接收机噪声对频偏估计精度带来的影响,并通过仿真进行了验证。本振光功率为10 d Bm时,当接收功率高于-47 d Bm,误码率优于10-4;将接收功率提高10 d B后,频偏估计标准差小于370 k Hz。展开更多
The influence of the nonlinear propagation effect on three 400 Gb/s/ch （400G） optical fiber communication systems with typical modulation formats, dual-carrier 16-quadrature amplitude modulation （16QAM）, single-ca...The influence of the nonlinear propagation effect on three 400 Gb/s/ch （400G） optical fiber communication systems with typical modulation formats, dual-carrier 16-quadrature amplitude modulation （16QAM）, single-carrier 16QAM （single-16QAM）, and four-carrier quadrature phase-shift keying, are investigated. The received optical signal-to-noise ratio （OSNR）, affected by the nonlinear interference noise together with the amplified spontaneous emission noise, are compared with three 400G systems and a standard 100 Gb/s/ch system by numerical simulations. Both single channel and multichannel cases are considered. Single-16QAM is found to have the best OSNR among those modulation formats.展开更多
基金supported by the Innovation Fund for Technology Based Firms of Changchun of China (No.10ZC04)
文摘By introducing orthogonal frequency division multiplexing （OFDM） technology, a visible light communication （VLC） system using a 5~5 white LED array is studied in this paper. The OFDM transmitter and receiver are modeled through MATLAB/Simulink tool. The electrical-optical-electrical （EOE） response of the VLC channel, which is also the re- sponse of the detector, is derived based on Lambert＇s lighting model. Then the modeling on the overall OFDM/VLC system is established by combining the above three models together. The effects of the factors which include the digital modulation, Reed-Solomon （RS） coding, pilot form, pilot ratio （PR） and communication distance on the bit error rate （BER） of the system are discussed. The results show that through the use of RS coding, block pilot, quad- rate phase shift keying （QPSK） modulation and a suitable pilot ratio about 1/3, under the communication rate about 550 kbit/s, the BER can be dropped to below 10^-5, and the communication distance can reach 0.9 m.
文摘为适用CDMA各类收发机的射频本振的应用要求,研制了一种低杂散低相噪高分辨率的P波段频率合成器。利用DDS输出信号具有高分辨率和PLL具有窄带跟踪滤波特性,通过有效的频率规划和参数配置,规避了DDS由于相位截断近端杂散无法消除的缺陷,有效抑制了DDS中DAC非线性和幅度量化误差引起的宽带杂散。通过仿真分析了方案的可行性,设计了样品并进行了测试。结果显示,所设计的频率合成器输出频率范围为755 MHz^765 MHz,频率分辨率为100.5 k Hz,杂散优于-71 d Bc,相位噪声优于-105 d Bc/Hz@1 k Hz。
文摘卫星相干光通信在国外已经接近工程应用阶段,主流的传输接收方式为BPSK调制/零差探测,接收端用光锁相环(OPLL)进行载波恢复。但即使在今天,光锁相环的实现依然有难度,而且存在捕获时间过长等现象。文中借鉴了现在的研究热点技术——光纤通信中的频偏估计、载波相位恢复技术,针对星间激光通信中存在GHz量级大多普勒频移的工程背景,提出了一种基于DSP的频偏开环补偿算法。从理论上分析了该算法的原理,重点研究了激光器噪声和接收机噪声对频偏估计精度带来的影响,并通过仿真进行了验证。本振光功率为10 d Bm时,当接收功率高于-47 d Bm,误码率优于10-4;将接收功率提高10 d B后,频偏估计标准差小于370 k Hz。
基金supported by the National Key Scientific Instrument and Equipment Development Project of China under Grant No.2014YQ510403
文摘The influence of the nonlinear propagation effect on three 400 Gb/s/ch （400G） optical fiber communication systems with typical modulation formats, dual-carrier 16-quadrature amplitude modulation （16QAM）, single-carrier 16QAM （single-16QAM）, and four-carrier quadrature phase-shift keying, are investigated. The received optical signal-to-noise ratio （OSNR）, affected by the nonlinear interference noise together with the amplified spontaneous emission noise, are compared with three 400G systems and a standard 100 Gb/s/ch system by numerical simulations. Both single channel and multichannel cases are considered. Single-16QAM is found to have the best OSNR among those modulation formats.
