双极点滤波器在港口交通管制雷达中的应用

双极点滤波器是一种递归型的反馈积累检测器。它实现多分层的积累，既能减少信息损失，提高检测性能，又能节省设备，不失为一种优良的检测器。详细介绍了双极点滤波器的基本原理及其在天津港港口交通管制雷达中的具体应用。     

插值FIR视频积累器

扫描雷达的最优视频积累器因运算量大而难以实时实现.本文提出了一种新的FIR视频积累器——插值FIR积累器.与最优积累器相比,新积累器运算效率高,舍入噪声小.而且,它与最优积累器具有几乎相同的性能.因而新积累器具有较好的实用性.     

高频脉冲相参积累滤波器

提出一个具有能在未知多卜勒频移情况下不需分路的相参积累器,它比一般分路方案可以简单得多。因此在从噪声中发现微弱信号的角度来看,优于其他曾提出过的任何积累方案。文中分析了这种积累器的作用原理,提出了利用这种积累器组成的积累滤波器如何能对脉冲串高频信号获得最佳信噪比,并用模糊度函数的概念说明了这种积累滤波器的实质,指出它比脉冲串匹配滤波器更优越和具有较大的实现可能性。最后还讨论了利用这种设备进行雷达站设计的要点和某些工作参数的选择与考虑。     

两通道低延迟滤波器组的设计

本文提出了一种用有效的迭代拉格朗日乘子法设计精确重构的两通道低延迟滤波器组.该方法具有较高的计算效率,既能设计不同长度也能设计相同长度的滤波器组.文中给出了设计例子并与其它方法进行了比较.结果表明,用该方法设计的两通道低延迟滤波器组具有更高的阻带衰减.     

模块法设计FIR数字陷波器的一种新方法

在模块法设计ＦＩＲ数字滤波器的基础上，提出一种设计ＦＩＲ数字陷波器的新方法。该方法将数字陷波器等效成为一个全通滤波器减去一个由基本频率单元构成的点通滤波器，进而推导出计算数字陷波器冲激响应的数学公式。该方法具有公式简单、物理概念清晰，陷波点频率不受模块数取整的约束，便于连续控制陷波点频率的优点。与窗口法设计相比，在同等凹口宽度下具有阶数减半的优点。同时，该方法可以推广至带阻滤波器的设计。     

用表面波综合器实现快速跳频

引言各种含有扩频数据通信线路的军用和商用系统,需要高频谱纯度、低噪声、精确、快速跳频的信号源或综合器。跳频速度小于1μs的不能采用锁相环。直接综合是用开关矩阵来选择连续工作的信源,然后混合产生输出频率,其跳频速度几乎和开关本身的速度一样快。因而,直接综合器可以容易地在零点几微秒范围内改变频率。低成本的、结构紧凑的直接综合器,要求带有相同特性的滤波器组(Banks)。声表面波(SAW)滤波器是一种合乎逻辑的选择。具有表面波滤波器组的直接综合器示于图1。图中说明了     

自适应幅值加权的理论分析与实现

本文提出用一种自适应幅值加权方法,对开环自适应速度补偿二次对消器级联8点FFT窄带滤波器组构成的MTD系统函数进行自适应幅值修正,使滤波器组中各滤波器的最高响应能在自适应速度补偿过程中保持不变,同时还推导出最简8点FFT运算公式,最后给出电路实现框图。     

用于回波对消器的数字横向滤波器积累误差的计算

本文针对用于回波对消器的数字横向滤波器,介绍了一种按二项式分布计算积累误差的大小和概率的方法,其结果以归一化形式作了图形描述,它可以用来确定横向滤波器的算法结构。现已表明,只有当系数的数目较多或超越概率值较大时,才能明显地减小由误差统计造成的积累误差。     

调制混合滤波器组的宽带模拟信号采样研究

对于超宽带模拟信号,很难用单个模拟数字转换器（ADC）直接进行采样。该文提出了一种新的并行调制混合滤波器组结构用于实现超宽带模拟信号的采样,首先,将每一路宽带模拟输入信号进行余弦调制,并用相同的低通模拟滤波器均匀分割输入信号的带宽;然后,采用相同的ADC将子带信号数字化;各路子带信号通过上采样器后用数字综合滤波器综合得到原宽带模拟输入信号的数字重构。综合滤波器采用总体最小二乘准则下的特征值滤波器设计方法得到。本文所提出的系统结构不需要使用高速的采样保持电路,降低了系统实现的难度,并且设计的系统具有与其它混合滤波器组相近的重构性能。仿真结果表明了本方法的有效性。      

电流传输器椭圆低通滤波器的一种综合方法

根据基本电流传输器电路及其特性,构造了同相电流积分器和反相电流积分器及多输出电流跟随器电路。并应用相互互易网络原理,提出了一种由LC滤波器原型电路到有源RC滤波器电路,再到基于电流传输器的电流模滤波器的综合方法,它们具有相同的传递函数和相同的元件灵敏度。综合方法简单易行,这对于电流模模拟信号处理是十分有用的。     

适宜集成的KHN滤波器设计

为了获得高精度的电压模KHN滤波器,以Deboo积分器为原型,先给出一种高精度、易集成的变形Deboo积分器,再借助Meson公式,用变形Deboo积分器设计出极点频率为31.8 kHz、品质因素为1、通带增益为2的通用电压模KHN滤波器.该电路不仅可同时实现高通、带通和低通输出,且极点频率与品质因素能实现正交、精确调节,电路的参数取决于电阻比,两积分电容接地,因而适合单片集成技术.计算机仿真结果与理论分析一致.     

A feedforward excess-phase cancellation technique for integrators

Integrators are useful analogue function blocks. A representative application of integrators is a continuous-time filter on an integrated circuit. Excess phase shift of integrators is one of the most severe problems, because excess phase shift at the unity gain frequency degrades the frequency characteristics of the filters. This paper describes a feedforward excess-phase cancellation technique. The proposed technique is applied to integrators which have feedback with an amplifier. The proposed idea is verified by experiment. It is shown that the excess-phase shift due to the gain-bandwidth product of operational amplifiers is cancelled. The proposed technique is useful for realization of integrated continuous-time filters using integrators because extra capacitors are unnecessary. An integrator with the excess-phase cancellation and a third-order leapfrog filter using the integrator are designed and demonstrated by HSPICE simulation. The integrator has a parasitic pole whose frequency is proportional to the unity gain frequency. The simulation results show that the phase characteristics are improved by the proposed technique over the wide range of the unity gain frequency.     

切比雪夫Ⅱ型模拟高通滤波器的设计及实现

提出了一种基于反相积分器的信号流图来实现切比雪夫Ⅱ型模拟高通滤波器的方法。首先,基于归一化切比雪夫Ⅱ型模拟低通滤波器极点分布的特点,推导出归一化切比雪夫Ⅱ型模拟低通滤波器零极点和转移函数的公式,得到归一化切比雪夫Ⅱ型模拟低通滤波器设计的步骤;然后,基于频率变换与逆变换,提出一种利用归一化切比雪夫Ⅱ型模拟低通滤波器来设计切比雪夫Ⅱ型模拟高通滤波器的方法;最后,给出了利用归一化切比雪夫Ⅱ型模拟低通滤波器来设计切比雪夫Ⅱ型模拟高通滤波器的实例及其实现电路。     

用AOA Deboo积分器设计通用二阶电流模滤波器

为了获得高精度的通用二阶电流模滤波器,根据伴随网络的概念,以基于VFA电压模Deboo积分器为原型,先给出了AOA电流模Deboo积分器,再给出AOA电流模多路输出比例电路,最后设计出了极点频率为31.8kHz,品质因素为1,通带增益为4的通用二阶电流模滤波器.该电路的参数取决于电阻比,两积分电容接地,因而适合VLSI单片集成技术.计算机仿真与理论分析一致.     

New resistorless and electronically tunable realization of dual-output VM all-pass filter using VDIBA

In this paper, a new active element called voltage differencing inverting buffered amplifier (VDIBA) is presented. Using single VDIBA and a capacitor, a new resistorless voltage-mode (VM) first-order all-pass filter (APF) is proposed, which provides both inverting and non-inverting outputs at the same configuration simultaneously. The pole frequency of the filter can be electronically controlled by means of bias current of the internal transconductance. No component-matching conditions are required and it has low sensitivity. In addition, the parasitic and loading effects are also investigated. By connecting two newly introduced APFs in open loop a novel second-order APF is proposed. As another application, the proposed VM APF is connected in cascade to a lossy integrator in a closed loop to design a four-phase quadrature oscillator. The theoretical results are verified by SPICE simulations using TSMC 0.18 μm level-7 CMOS process parameters with ±0.9 V supply voltages. Moreover, the behavior of the proposed VM APF was also experimentally measured using commercially available integrated circuit OPA860 by Texas Instruments.     

基于CMOS对数域积分器的小波变换模拟VLSI实现

提出了一种基于CMOS对数域积分器的连续Marr小波变换模拟VLSI实现方法.构造了Marr母小波时域逼近函数模型,用Levenbery-Marquardt非线性最小二乘法求解模型参数最优解,得到母小波逼近函数.设计了以CMOS对数域积分器为积木块的小波变换电路,该电路由冲激响应为母小波逼近函数及其伸缩函数的滤波器组构成,滤波器组采用低灵敏度的IFLF结构进行综合.SPICE仿真结果表明该方法的可行性.     

具有寄生极点的二阶电流模式滤波器的可调性

积分器寄生极点离主极点不是很远时,会引起全集成滤波器参数的偏差。文中分析了积分器有限直流增益和非主极点的影响,给出了二阶滤波器极点频率和品质因数的微变公式,研究了滤波器的可调控性。在此基础上,提出了增益可调型电流模式连续时间积分器,用这种积分器实现的滤波器能实现fp和Q的双调控。     

THEORY AND DESIGN OF UNIFORM FILTER BANKS USING ALL-PASS FILTERS

In this paper,the theory of uniform filter banks using all-pass tilters is furtherdeveloped.A new structure of two stage filter banks using all-pass filter is proposed,The pre-stage is half-band filter with period,the post-stage is two sets of band-pass filter banks.Thepre-stage filter stop-band just controls the don't-care-band of the post-stage filter banks usingall-pass polyphase,so as to realize a continuous stop-band property Moreover,a method ofsynthesizing filter bank is derived,which eliminates aliasing and amplitude distortions of theanalysis/synthesis system Finally,an example is given.     

Theory and design of two-parallelogram filter banks

It is well known that the analysis and synthesis filters of orthonormal DFT filter banks can not have good frequency selectivity. The reason for this is that each of the analysis and synthesis filters have only one passband. Such frequency stacking (or configuration) in general does not allow alias cancellation when the individual filters have good stopband attenuation. A frequency stacking of this nature is called nonpermissible and should be avoided if good filters are desired. In a usual M-channel filter bank with real-coefficient filters, the analysis and synthesis filters have two passbands. It can be shown that the configuration is permissible in this case. Many designs proposed in the past demonstrate that filter banks with such configurations can have perfect reconstruction and be good filters at the same time. We develop the two-parallelogram filter banks, which is the class of 2-D filter banks in which the supports of the analysis and synthesis filters consist of two parallelograms. The two-parallelogram filter banks are analyzed from a pictorial viewpoint by exploiting the concept of permissibility. Based on this analysis, we construct and design a special type of two-parallelogram filter banks, namely, cosine-modulated filter banks (CMFB). In two-parallelogram CMFB, the analysis and synthesis filters are cosine-modulated versions of a prototype that has a parallelogram support. Necessary and sufficient conditions for perfect reconstruction of two-parallelogram CMFB are derived     

A multiplexed switched capacitor filter bank

A technique is introduced which allows several integrator capacitors to be multiplexed onto a single operational amplifier. As a result, the op amp can be shared by several switched capacitor filter channels, drastically reducing the number of op amps required for filter banks. Twenty second-order filters have been implemented in a circuit using only two op amps and 2.5 mm/SUP 2/. The design of this system is presented and its performance is discussed. Some loss of signal energy is shown to occur during the multiplexing operations, which reduces filter Q. Causes of this charge loss are described, and its effects on performance are modeled. The design of the op amp used is presented, which incorporates a new system of input stage biasing and differential to single-ended conversion, as well as other features.