DPA-260音箱处理器

DPA-260音箱处理器为4声道输入,3分频2声道输出。此音箱分频系统中,每个输出频段可设定参数的项目为:高通滤波器、低通滤波器、延时时间、限幅方式、相位等,所有设置状态可保存在记忆中,有1个工厂预设状态,有9个用户自定义设置状态。通过设定机器,可接到RS485,USB端口,由外部控制来操作本机,同时有一路数字同SPDIF输入。     

低通型阻抗匹配网络的简捷设计

本文研究Ｂｕｔｔｅｒｗｏｒｔｈ响应和Ｃｈｅｂｙｓｈｅｖ响应低通型阻抗匹配网络的简捷设计，给出了设计２阶和４阶阻抗匹配网络旭一元件值显公式和计算高阶阻抗匹配网络元件值的公式，从而把复杂的设计过程简化成简单的数值计算。     

APF中数字低通滤波器的设计及仿真实现

文中介绍了基于瞬时无功功率理论的ip-iq谐波检测方法及对低通滤波器的要求,分析了数字低通滤波器的类型、阶数及截止频率对有源电力滤波器谐波检测效果的影响。利用MATLAB仿真软件设计了二阶巴特沃思（Butter—worth）数字低通滤波器,对ip-iq谐波检测算法进行了仿真研究,仿真结果证明所选择的数字低通滤波器的正确性。     

LTC1569滤波器在信号调理模块中的应用

为实现抗混叠滤波,采用linear公司的滤波器LTC1569设计输出频率为0～2 kHz的信号滤波电路.通过实验验证利用LTC1569搭建的滤波电路对信号具有很好的滤波效果.     

一种新颖的开口环地面缺陷结构低通滤波器

提出了一种新颖的具有陡峭边带和宽阻带的小型化低通滤波器.通过把开口谐振环地面缺陷结构(Split-Ring Resonator Defected Ground Structure,SRR DGS)与阶梯阻抗梳状谐振器结合,提高了滤波器的选择特性,同时获得了宽阻带.对所提出的结构作了加工并进行了实物测量,测试结果表明:滤波器选择特性大于160 dB/GHz,在2.98 GHz到8.2 GHz范围内抑制度大于20 dB,而占用面积仅为20×25 mm~2.     

基于MATLAB用于谐波检测的数字低通滤波器的设计

有源电力滤波器谐波检测中数字低通滤波器的设计是关键,利用Matlab中的FDATool可以快速、方便地设计出符合要求的IIR滤波器,并进一步转化为VHDL语言描述的文件,并通过编译、仿真后可以利用FPGA实现。     

UHF波段六位数字移相器的研究与实现

对应用于相控阵雷达中的六位数字移相器的工作原理进行了深入的研究、并详细地介绍了它的设计方法和测试结果.主要叙述了采用高低通滤波器移相原理实现UHF波段的六位数字移相器,利用ADS软件设计仿真,实现了频带内高移相精度、低插入损耗和低VSWR等较好性能,最后通过矢量网络分析仪HP8753D对实物进行调试和检测.进而验证了设计方案.     

一种用于低电压集成锁相环的省面积的双通道环路滤波器

This paper proposes an area-saving dual-path loop filter（LPF）for low-voltage integrated phase-locked loops（PLLs）.With this LPF,output current of the lowpass-path charge-pump（CP）is B times（B〉1）as great as that of the integration-path CP.By adding voltages across these two paths,the zero-capacitance is magnified B times equivalently.As a result,the chip size is greatly reduced.Based on this LPF,a 1.2 V 3.5 GHz-band PLL is fabricated in SMIC 0.18μm RFCMOS technology.Its zero-capacitance is only 1/30 of that in conventional second-order LPFs. Measured data show that,at a frequency of 3.20 GHz,phase noise is–120.2 dBc/Hz at 1 MHz offset,reference spur is–72 dBc,and power is 24 mW.     

A Miniature Telemetric System for Freely Roaming Animals

Telemetric monitoring and control are the two critical aspects for a robot-rat. Development in this work is a telemetric system to record the electroencephalogram （EEG） from adult freely roaming animals. The system consists of two separated components： the transmit-end system, which consists of the preamplifier, the LPF （low-pass filter） and the transmitter, and the receive-end system, which consists of the receiver, the interface of receive-end and PC. The transmit-end system with light weight （10 g including battery） and small size （20 mm×50 mm） is fettered on the back of the rat. The EEG signal is modulated at the RF frequency of 2.4 GHz by nRF24E1 and transmitted by the antenna. The system can measure the EEG signal of the rat in freely roaming over a wireless transmission distance up to 8 m, and provide a new platform for behavioral and neurophysiological experiments.     

Design of an EEG Preamplifier for Brain-Computer Interface

As a non-invasive neurophysiologieal index for brain-computer interface （BCI）, electroencephalogram （EEG） attracts much attention at present. In order to have a portable BCI, a simple and efficient pre-amplifier is crucial in practice. In this work, a preamplifier based on the characteristics of EEG signals is designed, which consists of a highly symmetrical input stage, low-pass filter, 50 Hz notch filter and a post amplifier. A prototype of this EEG module is fabricated and EEG data are obtained through an actual experiment. The results demonstrate that the EEG preamplifier will be a promising unit for BCI in the future.