First-order SC filter section with interpolating output

A first-order switched-capacitor filter section with linear interpolation in the output signal is presented. The circuit, which is insensitive to parasitic capacitances, can be useful as a cascaded section in a filter, but may also be included as an output stage in, for example, leapfrog filters.     

一种使用滤波器实现射频功放输出口ESD防护的方法

文章分析人体模型电压波形的基波频谱范围,使用射频滤波器对人体模型电压波形的基波滤除,以实现对射频功放器件输出口的ESD防护。     

A recursive digital filter with maximally flat linear phase at an arbitrary specified frequency

An available recursive digital low-pass filter with constant group delay cannot be spectral transformed to give, for example, a bandpass filter which also has constant group delay. This correspondence describes a technique, using Gauss-Jordan elimination, to design a recursive digital filter with maximally flat linear phase at an arbitrary specified frequency.     

感应式频率域磁场传感器设计

为解决长期制约我国电磁法勘探技术发展的感应式频率域磁传感器研制问题,以法拉第电磁感应定律为基础,通过对磁芯材料研制、感应线圈绕制、输出信号的开环补偿以及电场干扰信号的梳状屏蔽技术的研究,总结出传感器研制调试方法,并成功研制感应式频率域磁传感器。测试与试验结果表明,该传感器具有在3～10 000 Hz的工作频带内幅频特性曲线平坦的特点,实测结果与进口传感器相当。满足物探电磁法测量需要。     

基于FPGA的高效可调频率滤波器

为了有效地改善滤波器的不可调频率系统性能,降低FPGA滤波器资源的消耗,提出基于FPGA的高效可调频率滤波器。该方法首先对可调频率滤波器进行硬件平台设计,硬件平台由单片机模块、FPGA波形模块、幅度模块、数字模型转换模块、低通滤波转换模块以及输入键盘模块和液晶显示屏模块构成。核心模块由MCU提供可调频率控制,以DDS技术产生的波形信号为依据,确定滤波器的信号强度,最后采用分布算法完成滤波器软件设计。实验证明,所提方法能够有效提高可调频率滤波器的准确度。     

SC filter circuit with decimation of sampling frequency

Realisation of a switched-capacitor filter circuit with decimation of the input sampling frequency is proposed. The circuit, which is compensated for the influence of parasitic capacitances, is useful as an input stage of an SC filter. It can also be used for the realisation of an integrator, based on Simpson's rule.     

Broadcast-and-select photonic ATM switch with frequency divisionmultiplexed output buffers

A photonic ATM switch has been developed with frequency division multiplexed (FDM) output buffers. The switch has a broadcast-and-select network architecture using fixed-frequency-channel transmitters and a passive star configuration. Although it has a simple structure, it can provide either broadcast or multicast switching. The output buffers, which resolve cell contentions, are comprised of fiber delay lines that can easily handle signal speed of over 10 Gb/s. Experimental switching of two-multiplexed 10 Gb/s cells with a 2.8-dB power penalty demonstrated high-speed switching     

A ripple control buck regulator with fixed output frequency

This paper presents a ripple control buck regulator for stepping down high-voltage adaptor or battery supplies to low-voltage CPU core supply in notebook computers. Methods and circuits are proposed to achieve fixed switching frequency operation. The control loop adjusts delay of the controller and thus controls the output frequency. This is done by using a phase-frequency detector (PFD) to lock the frequency of switching signal with the input clock. The delay value is determined automatically according to operating conditions. Simulation results showed fast load and line transient responses and fixed frequency operations in steady states. In addition, stability of the regulator is shown under a very low output-to-input voltage ratio condition that is difficult for conventional PWM controllers.     

Simple frequency/voltage convertor with low output ripple

A frequency/voltage convertor with theoretically zero output ripple is presented. It has a simpler structure and four times faster response than an earlier system. Moreover, it may easily be modified to a switched-capacitor version, if so desired.<>     

高输出阻抗多功能电流模式双二阶滤波器

提出了一种基于多输出端差动差分电流传送器的多功能电流模式滤波器电路结构。该电路用三个多输出端差动差分电流传送器，五个或四个接地电阻和两个接地电容，同时实现了反相和，或同相带通和低通或带通和高通滤波响应特性。分析并模拟了所提出的滤波器的传递特性，PSPICE仿真结果表明，所提出的电路方案正确有效。电路具有灵敏度低，输出阻抗高，滤波器固有频率ωo和品质因数Q相互独立可调，多功能的优点，适于实现全集成连续时间滤波器。     

能扩展微机输出端口的RC低通滤波器

几乎是摩尔定律的必然结果: 明年,微机将具有更多功能,软件开发团队也会有更宏大的构想.可惜,输出针脚的数量并未增加.找到一个多余输出端口用于诊断、测试或标准I/O都是很困难的.图1中的单一针脚"总线"以简单的附加硬件可提供无数的并行输出.带有RC低通滤波器的微机输出,控制串/并转换器HC164.     

滤波器频率响应的测量

至于测量要求频率响应的任何器件或网络,这一过程要采用扫频信号发生器和检波器或扫频接收机。为了测量大的衰减值,需要采用信号电平很高或很灵敏的检波器—接收机,或者是二者折中的器件,以便产生良好的结果。如果     

形成单输出滤波器的PC配置RLC谐振器

本期"设计实例"栏目介绍的一种低功耗仪器用的通用滤波器电路,你可以使用并行端口通过PC对它进行编程.这种滤波器电路不用数字式电位器而使用模拟开关和锁存器来进行数字控制(图1和图2).只要在PC上运行简单的软件代码,你就可以配置出一种可靠的设计,用作低通滤波器、高通滤波器或带通滤波器,并且还可以选择所需的中心频率ω0(表1).与类似的可控制设计(参考文献1)不同的是,这一设计是一种每次只有一个输出的滤波器.很多对功耗敏感的系统并不需要同时滤波功能.     

X波段发卡式带通滤波器设计

采用引入传输零点的方法设计了一款发卡式带通滤波器。该滤波器由5个发卡单元构成,中心频率为8.6GHz.。通过在第2和第4个发卡谐振器上并联微带开路线的方法引入传输零点,来实现更好的边带抑制。通过调节并联微带线的长度来控制传输零点的位置,实现对边带抑制效果的有效控制。     

A low-noise widely tunable Gm-C filter with frequency calibration

A fourth-order Gm-C Chebyshev low-pass filter is presented as channel selection filter for reconfigurable multi-mode wireless receivers. Low-noise technologies are proposed in optimizing the noise characteristics of both the Gm cells and the filter topology. A frequency tuning strategy is used by tuning both the transconductance of the Gm cells and the capacitance of the capacitor banks. To achieve accurate cut-off frequencies, an on-chip calibration circuit is presented to compensate for the frequency inaccuracy introduced by process variation. The filter is fabricated in a 0.13 μm CMOS process. It exhibits a wide programmable bandwidth from 322.5 kHz to 20 MHz. Measured results show that the filter has low input referred noise of 5.9 nV/√Hz and high out-of-band ⅡP3 of 16.2 dBm. It consumes 4.2 and 9.5 mW from a 1 V power supply at its lowest and highest cut-off frequencies respectively.     

FDM-channel selection filter using arrayed-waveguide gratingmultiplexer with input and output switches

A novel configuration is reported for a tunable channel-selection filter that employs an arrayed-waveguide grating (AWG) multiplexer and optical switches. The filter requires only 2(√N-1) 1×2 switch elements to select one of N frequency-division-multiplexed (FDM) channels. A filter for 100 GHz-spaced 16 FDM channels is demonstrated with an AWG 16×16 multiplexer and six 1×2 switches     

Deadbeat control of a three-phase inverter with an output LC filter

The discrete-time control of a three-phase inverter with an output LC filter is described based on space vectors. The mathematical model of the inverter-filter system is first obtained by using space vectors to represent three-phase quantities. Deadbeat control laws are derived for no-load and resistive-load cases. Then, a deadbeat control law is obtained for the case when the load draws current of any waveshape from the inverter-filter. It is shown that deadbeat control of output voltage can be achieved in two control steps. The manipulated variable, which is the voltage vector demanded from the inverter, is implemented using the space vector modulation technique. Simulation results for various operating conditions are presented     

Universal capacitor-grounded voltage-mode filter with three inputs and a single output

For the first time, a universal voltage-mode filter with three inputs and a single output has been realized by employing two 'grounded' capacitors in addition to two active current conveyors and two resistors. The proposed circuit offers the following advantageous features: simultaneous realization of voltage-mode low-pass, band-pass, high-pass, notch and all-pass filter responses from the same configuration; no requirement of critical component matching conditions; no requirement of inverting-type voltage input signal; employment of two grounded capacitors ideal for integration; and low active and passive sensitivity performance. H-SPICE simulation results confirm the theoretical analysis.     

实时扰动频率控制的自适应陷波器研究

针对工频干扰范围在49Hz~51Hz区间波动时,传统自适应陷波器存在滤除精度不高的问题。本研究采用快速傅立叶变换实时提取工频干扰频率值,并设计补零法在保证精度的前提下提高系统实时性。在FPGA上采用下降沿检测获得快速傅立叶变换结果的极值,通过排序法拟合出干扰频率。设计基于实时扰动频率控制的自适应陷波器,在线改变自适应陷波器的陷波频率,实时补偿干扰频率变化。研究结果表明,实时扰动频率控制的自适应陷波器,能够更好滤除49Hz~51Hz范围工频干扰,提高滤波性能。     

Metallic E-plane filter with cavities of different cutoff frequency

A planar integrated circuit filter with multiple all-metal inserts and multiple abrupt waveguide step-wall discontinuities is introduced which achieves broadband high attenuation in the second stopband. The design is based on field expansion into suitably normalised eigenmodes which yield directly the modal S-matrix. This theory allows the immediate inclusion of both the higher-order mode interaction at all discontinuities and the finite thickness of the inserts. Computer-optimised design data for a five-resonator Ka-band prototype filter at 27 GHz midband frequency provide a minimum stopband attenuation of 50 dB between 27.5 and 44.5 GHz.