单缆实现多星多机接收的系统设计

设计一完整的电路系统解决数字卫星广播接收中的单电缆多用户接收问题,并重点分析电路中信号的频率搬迁和信道复用过程,以及实现过程中解决控制命令冲突的方法.     

CATV宽带IP网络建设的探讨

随着因特网的迅速发展,CATV宽带IP网络的建设变得越来越重要。首先介绍了中国CATV的发展现状及其优势,然后详细讨论了CATV宽带IP网络的建设,最后了CATV宽带网络提供的服务和存在的问题,并对CATV网络的建设提出了一些看法。     

Ni含量对Nd_2Fe_(17)磁粉吸波性能的影响

采用高能球磨和微氧化气氛热处理制备了Nd2(Fe1–xNix)17(x=0,0.05,0.15,0.50)吸波粉体,研究了Ni的含量对NdFeNi粉体的相组成和吸波性能的影响。结果表明:当x=0,0.05,0.15和0.50时,样品的组成相均是Nd2Fe17、α-Fe和Nd2O3相。NdFe样品对电磁波的损耗以介电损耗为主;NdFeNi样品对电磁波的损耗以磁损耗为主。随着Ni含量的增加,样品对微波的吸收峰逐渐向低频移动,且其反射率逐渐升高。     

一种适合3G移动的微支付方案

本方案提出利用改进后3G入网认证机制中密钥和随机数,结合AES算法生成安全性高的一次性签名,且计算量和存储量很少,具有不可否认性,还利用了登录第三方网站后生成的用户临时标识,具有很好的匿名性和不可跟踪性。其中商家受到第三方的监视和管理,防止用户和商家的欺诈,用户收到商品后对商家的信用进行评价,具有公平性。该方案交易灵活、效率高,适合3G用户实行微支付交易。     

5.2 mW 61 dB SNDR 15 MHz Bandwidth CT ΔΣ Modulator Using Single Operational Amplifier and Single Feedback DAC

We propose an architecture that reduces the power consumption and active area of such a modulator through a reduction in the number of active components and a simplification of the topology. The proposed architecture reduces the power consumption and active area by reducing the number of active components and simplifying the modulator topology. A novel second‐order loop filter that uses a single operational amplifier resonator reduces the number of active elements and enhances the controllability of the transfer function. A trapezoidal‐shape half‐delayed return‐to‐zero feedback DAC eliminates the loop‐delay compensation circuitry and improves pulse‐delay sensitivity. These simple features of the modulator allow higher frequency operation and more design flexibility. Implemented in a 130 nm CMOS technology, the prototype modulator occupies an active area of 0.098 mm² and consumes 5.23 mW power from a 1.2 V supply. It achieves a dynamic range of 62 dB and a peak SNDR of 60.95 dB over a 15 MHz signal bandwidth with a sampling frequency of 780 MHz. The figure‐of‐merit of the modulator is 191 fJ/conversion‐step.     

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国外输气干线的增压,都以燃气轮机作压缩机的动力。我国自50年代起生产了一批样机,主要用于发电。本文提出,在国内即将引进生产新型燃气轮机时,应考虑解决适用于干线增压的技术配套等问题。     

EPON技术在有线电视网络宽带接入中的应用

在分析目前国内有线电视网络宽带接入技术的基础上，介绍了EPON（以太网无源光网络）技术。根据有线电视HFC网络结构，探讨了EPON技术在有线电视网络宽带接入中应用的可能性，并且提出了在有线电视宽带网络中应用EPON技术的思路。     

H optimal approximation for causal spline interpolation

In this paper, we give a causal solution to the problem of spline interpolation using H^∞ optimal approximation. Generally speaking, spline interpolation requires filtering the whole sampled data, the past and the future, to reconstruct the inter-sample values. This leads to non-causality of the filter, and this becomes a critical issue for real-time applications.Our objective here is to derive a causal system which approximates spline interpolation by H^∞ optimization for the filter. The advantage of H^∞ optimization is that it can address uncertainty in the input signals to be interpolated in design, and hence the optimized system has robustness property against signal uncertainty.We give a closed-form solution to the H^∞ optimization in the case of the cubic splines. For higher-order splines, the optimal filter can be effectively solved by a numerical computation. We also show that the optimal FIR (finite impulse response) filter can be designed by an LMI (linear matrix inequality), which can also be effectively solved numerically. A design example is presented to illustrate the result.     

应变花的平差计算及其在工程中的应用

根据自由网平差理论，提出了一种处理应变网络数据以确定该点应力状态的方法，推导出更符合实际、适应性更广泛的计算主应力公式结果表明，该方法能够充分利用所有的测试信息，大大地提高了处理实测应变数据的精度，效果良好因此，在验算金属支架强度、高层钢结构网架的可靠度等方面具有一定的应用价值