TN761 98010488Ge<sub>x</sub>Si<sub>1-x</sub>电光调制器与探测器的集成=Integrationof the Ge<sub>x</sub>Si<sub>1-x</sub>electro-optic modulator anddetector[刊,中]/李国正,高...TN761 98010488Ge<sub>x</sub>Si<sub>1-x</sub>电光调制器与探测器的集成=Integrationof the Ge<sub>x</sub>Si<sub>1-x</sub>electro-optic modulator anddetector[刊,中]/李国正,高勇,刘恩科（西安交通大学.陕西,西安（710049））//固体电子学研究与进展.-1997,17（1）.-87-91在Ge<sub>x</sub>Si<sub>1-x</sub>电光调制器和探测器已经问世的基础上,提出了一种将它们集成起来的结构,通过原理和工艺技术的分析,认为这种光电集成是完全可以实现的。图4参6（李瑞琴）TN761 98010489应用双面电极的PLZT横向电光调制器电场的精确解=Exact analysis of the electric field for transverseelectro-optic modulator using doublesidedelectrodes[刊,中]/叶宇煦,曾庆济,段耀明（上海交通大学光纤技术研究所.上海（200052））//光学学报.-1997,17（5）.展开更多
In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances i...In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances in terms of data channel coding which might result in a signal structure where the symbol duration is shorter than the pseudo code period. This can generate some difficulties in the DSSS signal acquisition due to the polarity inversion caused by the data modulation. To eliminate the influence due to polarity inversion, this paper proposes a novel acquisition algorithm based on the simultaneous search of the code phase, data phase and Doppler frequency. In the proposed algorithm the data phase is predicted and the correlation period for the coherent integration can be set equal to the symbol duration. Then non-coherent accumulation over different symbol is implemented in order to enhance the acquisition algorithm sensitivity; the interval of non-coherent accumulation is the least common multiple between the symbol duration and the pseudo code period. The algorithm proposed can largely minimize the SNR loss caused by data polarity inversion and enhance acquisition performance without a noticeable increase in hardware complexity. Theoretical analysis, simulation and measured results verify the validity of the algorithm.展开更多
文摘TN761 98010488Ge<sub>x</sub>Si<sub>1-x</sub>电光调制器与探测器的集成=Integrationof the Ge<sub>x</sub>Si<sub>1-x</sub>electro-optic modulator anddetector[刊,中]/李国正,高勇,刘恩科（西安交通大学.陕西,西安（710049））//固体电子学研究与进展.-1997,17（1）.-87-91在Ge<sub>x</sub>Si<sub>1-x</sub>电光调制器和探测器已经问世的基础上,提出了一种将它们集成起来的结构,通过原理和工艺技术的分析,认为这种光电集成是完全可以实现的。图4参6（李瑞琴）TN761 98010489应用双面电极的PLZT横向电光调制器电场的精确解=Exact analysis of the electric field for transverseelectro-optic modulator using doublesidedelectrodes[刊,中]/叶宇煦,曾庆济,段耀明（上海交通大学光纤技术研究所.上海（200052））//光学学报.-1997,17（5）.
基金the support of the National High Technology Research and Development Program of China (863) (Grant No. 2012AA1406)
文摘In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances in terms of data channel coding which might result in a signal structure where the symbol duration is shorter than the pseudo code period. This can generate some difficulties in the DSSS signal acquisition due to the polarity inversion caused by the data modulation. To eliminate the influence due to polarity inversion, this paper proposes a novel acquisition algorithm based on the simultaneous search of the code phase, data phase and Doppler frequency. In the proposed algorithm the data phase is predicted and the correlation period for the coherent integration can be set equal to the symbol duration. Then non-coherent accumulation over different symbol is implemented in order to enhance the acquisition algorithm sensitivity; the interval of non-coherent accumulation is the least common multiple between the symbol duration and the pseudo code period. The algorithm proposed can largely minimize the SNR loss caused by data polarity inversion and enhance acquisition performance without a noticeable increase in hardware complexity. Theoretical analysis, simulation and measured results verify the validity of the algorithm.
