排序方式: 共有36条查询结果,搜索用时 31 毫秒
1.
This paper gives a brief and systematic presentation of the computer simulation techniques of satellite communications, especially for a mobile satellite channel, based on a summarization of the author's exploration and experience in this area. It includes the equivalent complex baseband notation (ECBN) method, a very convenient mathematical form for software simulation; development of a multi-functional and expandable channel simulation system on a computer from L-band to Ka-band; channel impulse or frequency response estimation in real time by the technique burst-mode link analyser with least-squares algorithm (BMLA/LS), modelling and simulation of the channel fast fading due to multipath and shadowing; acquisition of the equivalent normalized binary signal-to-noise ratio (Eb/N0) data at the channel input; and bit-error rate (BER) evaluation by the directly error-counting approach and the computational approach at the channel output in simulation. 相似文献
2.
3.
本文从卫星上行系统的使用出发,介绍了利用频谱分析仪对接收Eb/N0的测量方法及对该值产生影响的相关因素,说明其对确定上行功率的参考意义。 相似文献
4.
The burst mode link analyser with least squares algorithm (BMLA/LS) is a real-time impulse or frequency response extraction (IRE/FRE) technique of a satellite communication channel, originated and explored by the author. This paper summarizes some key technical points of the BMLA/LS and presents its novel simulation results and applications in a land-mobile DBPSK/DQPSK satellite channel at Ka-band, including the channel additive white Gaussian noise (AWGN) effect on IRE/FRE by BMLA/LS, and the instantaneous IRE/FRE in a Rician channel with multi-path reflection, in a shadowed channel by trees and in a combinational fading channel, and their comparisons and conclusions. 相似文献
5.
刘维倩 《国外电子测量技术》2010,29(5):35-37
Eb/n0是衡量接收机性能的重要指标之一,但难以直接测量。在分析Eb/n0与S/N之间关系的基础上,推导出二者的数学换算式,从而得出可通过测量信号功率S和噪声功率N,再经计算得到Eb/n0的理论依据。详细阐述了实际使用频谱分析仪进行S和N测量的方法和具体操作步骤,对该测量方法进行了实验验证并简要分析了测量不确定度来源。 相似文献
6.
在前人研究的基础上,提出单桩沉降预测的神经网络简化模型,以已测单桩沉降值作为训练网络输出值进行学习,根据训练好的网络来预测区域其他桩的沉降,工程算例模拟结果表明,利用神经网络简化模型预测单桩沉降体现了其处理非线性问题的能力,其预测的结果还是令人满意的。 相似文献
7.
根据<卫星广播电视地球站工程技术验收规定>和<验收测试方案>的技术要求,结合广东卫星地球站的具体情况,讨论数字压缩DVB-S标准的卫星上行系统信源编码后的指标测试,不包括MPEG-2编码器的码流分析、系统视音频指标等项目的测试. 相似文献
8.
分析有线数字电视和有线模拟电视抗干扰能力的差异,指出有线数字电视信号经过载波调制处理以后,它的抗干扰能力大大降低了,因此有必要对有线数字电视抗干扰的性能进行重新评价,提出"当系统网络没有故障时,有线数字电视抗干扰;当系统网络发生故障时,有线数字电视怕干扰;当有线数字电视出现问题时,系统网络必然有故障"的初步结论,并介绍一些有线数字电视发生故障的现象和维修、预防的方法。 相似文献
9.
The electrical and the optical properties of organic light-emitting devices (OLEDs), with and without multiple heterostructures consisting of N, N-bis-(1-naphthyl)-N, N-diphenyl-1,1-biphenyl-4,4-diamine (NPB)/5,6,11,12-tetraphenylnaphthacene (rubrene) acting as a hole transport layer (HTL), were investigated. The OLEDs with 3 periods of NPB/mixed rubrene:NPB multiple heterostructures acting as an HTL showed the highest luminances and efficiencies. While the electroluminescence (EL) peak corresponding to the rubrene layer did not appear for the OLEDs with 3 periods of NPB/mixed rubrene:NPB multiple heterostructures, only the EL peak related to the tris (8-hydroxyquinoline) aluminum layer was observed. The Commission Internationale de l’Eclairage chromaticity coordinates of the OLEDs with 3 periods of NPB/mixed rubrene:NPB multiple heterostructures at 14 V were (0.321, 0.531), indicative of a deep stabilized green color. 相似文献
10.
Inkjet-printed InGaZnO thin film transistor 总被引:2,自引:0,他引:2
Gun Hee Kim 《Thin solid films》2009,517(14):4007-1340
We report inkjet-printed InGaZnO (IGZO) thin film transistors (TFTs). IGZO ink was prepared by dissolving indium nitrate hydrate, gallium nitrate hydrate and zinc acetate dihydrate into 2-methoxyethanol with additional stabilizers. The resulting films were inkjet-printed with a resolution of 300 dots per inch using droplets with a diameter of 40 µm, and a volume of 35 pl. The films exhibited high optical transparency in the visible range and had a polycrystalline phase of InGaO3(ZnO)2 after thermal annealing treatment. The chemical composition of this IGZO sample was also determined, and shown to have high stoichiometric characteristics of low oxygen deficiency. The TFTs with a conventional inverted staggered structure using inkjet-printed IGZO as an active channel layer had a field-effect mobility of ~ 0.03 cm2/Vs in saturation region and an on-to-off current ratio greater than ~ 104. 相似文献