Design of digital allpass‐based two‐channel quincunx QMF banks

This paper presents a novel structure for constructing two‐channel quincunx quadrature mirror filter (QQMF) banks. The analysis and synthesis filters of the QQMF bank are composed of two‐dimensional (2‐D) recursive digital allpass filters with symmetric half‐plane support regions. Using the 2‐D doubly complementary half‐band property possessed by the analysis and synthesis filters, we facilitate the design of the digital allpass‐based two‐channel QQMF banks. For finding the coefficients of the 2‐D recursive symmetric half‐plane digital allpass filters, the design problem is appropriately formulated to result in an optimization problem that can be solved by using a weighted least‐squares algorithm in the minimax (L_∞) optimal sense. The novelty of the proposed design method is that the designed 2‐D QQMF bank achieves perfect magnitude response and possesses satisfactory phase response without requiring extra phase equalizer. Simulation results are also provided for illustration and comparison. Copyright © 2012 John Wiley & Sons, Ltd.     

基于NCP理论的光滑牛顿法在无功优化中的应用

采用经典的无功优化模型,以系统网损最小为目标函数。依据非线性互补理论,构造NCP函数,将KKT条件中的不等式约束转换为等价的非线性方程,然后用牛顿法求解。用同样的方法来处理离散变量,即构造一个与离散变量的约束条件等价的离散NCP函数,嵌入牛顿法中迭代计算。最后,由经典IEEE系统的计算结果表明：该算法收敛速度与传统方法相当,能有效降低网损,具有大范围收敛性。     

三维热弹性接触问题的互补方程及有限元解法

通过定义接触面滑动屈服函数和流动势函数,得出了热接触边界的互补方程.基于虚功原理和接触单元技术,推导了热应力作用下三维弹性接触问题的有限元方程,在该方程中引入了接触伪荷载,以反映接触状态变化对荷栽项的影响.在遮代求解过程中采取每作两次迭代进行一次加速的策略,显著提高了求解效率.     

Scaling down of organic complementary logic gates for compact logic on foil

In this work, we realize complementary circuits with organic p-type and n-type transistor integrated on polyethylene naphthalate (PEN) foil. We employ evaporated p-type and n-type organic semiconductors spaced side by side in bottom-contact bottom-gate coplanar structures with channel lengths of 5 μm. The area density is 0.08 mm² per complementary logic gate. Both p-type and n-type transistors show mobilities >0.1 cm²/V s with V_on close to zero volt. Small circuits like inverters and 19-stage ring oscillators (RO) are fabricated to study the static and the dynamic performance of the logic inverter gate. The circuits operate at V_dd as low as 2.5 V and the inverter stage delay at V_dd = 10 V is as low as 2 μs. Finally, an 8 bit organic complementary transponder chip with data rate up to 2.7 k bits/s is fabricated on foil by successfully integrating 358 transistors.     

炼油装置吸收稳定系统双塔节能流程开发现状及进展

综述了近年来炼油装置中双塔吸收稳定系统的流程研究和开发现状。对公开发表专利技术和企业技术改造流程进行梳理归纳;对目前吸收稳定系统新型双塔节能流程进行了对比和分析,提出了吸收稳定流程发展面临的趋势和应解决的主要问题。     

基于90nm CMOS工艺的60GHz射频接收前端电路设计

设计了一款用于中国60 GHz标准频段的射频接收前端电路。该射频接收前端采用直接变频结构,将59～64 GHz的微波信号下变频至5～10 GHz的中频信号。射频前端包括一个四级低噪声放大器和电流注入式的吉尔伯特单平衡混频器。LNA设计中考虑了ESD的静电释放路径。后仿真表明,射频接收前端的转换增益为13.5～17.5 dB,双边带噪声因子为6.4～7.8 dB,输入1 dB压缩点为-23 dBm。电路在1.2 V电源电压下功耗仅为38.4 mW。该射频接收前端电路采用IBM 90 nm CMOS工艺设计,芯片面积为0.65 mm2。     

多载频相位编码信号的多普勒处理研究

由于多载频相位编码信号在频谱利用率、模糊函数以及包络峰均比三者之间达到了较好平衡,因而在近年来备受关注。针对这种雷达信号,研究基于子载频分离的脉冲多普勒处理技术,详细推导整个处理过程,分析速度对回波正交性及多普勒处理的影响,提出一种解决速度模糊的新方法。仿真分析表明,该方法能够较好地估计目标真实速度,对噪声具有一定的稳健性。     

提高便携式OTDR动态范围的方法研究及实现

使用格雷互补码脉冲序列作为光时域反射仪（OTDR）探测光脉冲,并结合相关处理,可以在不影响空间分辨率的前提下提高动态范围,增加有效的测量距离。文章将格雷互补码应用于便携式OTDR,对强噪声环境下信噪比改善特性进行了分析和仿真,并通过实验验证了理论的正确性。通过数字平均进行强噪声抑制,再相关处理能获得更好的响应曲线。在编码长度为256时,通过先数字平均,再相关运算,便携式OTDR动态范围可提高9dB。     

基于CDMA技术的FBG传感系统研究

基于码分多址(CDMA)技术,采用格雷互补序列对光源进行调制,使用相关运算对接收信号进行解调.该方法具有传感器间串音小和系统信噪比高等优点.基于该方法搭建了光纤Bragg光栅(FBG)传感实验平台,对其温度传感特性进行了实验研究.结果表明:系统具有温度响应线性度好和串音低的优点.