Current mode single-input multi-output MOSFET-only filter

In this paper, a very simple topology of a current mode MOSFET-only filter with single-input and multi-output is proposed. It is very important to emphasize that it is possible to obtain five of the filter functions, namely low-pass (LP), band-pass (BP), high-pass (HP), band-stop (BS) and all-pass (AP) using the proposed topology without using external passive elements. The core circuit of the proposed filter employs only four MOS transistors; therefore, it occupies very small chip area. It is also possible to adjust the filter gain with the biasing voltage. In addition, the circuit exhibits a very low input impedance and also high output impedances which make it possible for cascading. The MOSFET capacitances which determine the transfer functions are all grounded, so physical capacitances can be used instead of MOSFET parasitic capacitances to operate the filter at very low frequencies. Moreover, proposed filter structure has low supply voltage as 1 V in order to be applicable to low voltage operations. Detailed simulation results, including noise and Monte Carlo analysis, are provided using 0.18 µm TSMC technology parameters to verify the feasibility of the filter circuit.     

巴特沃斯低通滤波器的仿真设计

设计了一个巴特沃斯低通滤波器,并用电路仿真软件对其进行了仿真,幅频特性和相频特性较好,通带内频率特性平坦,且不存在波浪起伏现象,阻带内的曲线缓缓变化到零,所得指标能满足要求,能达到较好的滤波效果。     

一种Butterworth带通滤波器的设计与实现

提出一种基于MAX260的Butterworth带通滤波器设计方法.介绍了设计Butterworth滤波器的基本原理,以及利用MAX260实现该种滤波方式的具体过程.在实验室环境下举出具体实例实现了四阶Butterworth带通滤波器,并验证了其滤波性能.测试结果表明该方法具有较好的滤波效果.由于该方法中信号滤波由有源程控滤波器芯片完成,可降低微控制器的运算负担,有利于提升系统性能.     

Low-distortion 4th order programmable Butterworth filter

A highly linear 4th order low-pass filter with one decade frequency programmability and 39 dB gain programmability is presented in this paper. Low distortion is achieved through the use of the inherently linear current division principle. The paper provides the basic equations of the Butterworth filter and shows how to achieve programmability. A prototype was fabricated in a 0.35 μm–3.3 V CMOS process and experimental measurements prove the high linearity of the system. A distortion level better than −65 dB for 2 V_p-p output signal is obtained.     

基于分数阶巴特沃斯滤波器的新型超级电容器

超级电容器作为一种新型储能元件在各个领域具有广阔的应用前景。由于超级电容固有特性不是整数阶的,因此建立一个精确且适用范围更广的模型具有重要的研究意义。介绍了超级电容器的基本模型,利用分数阶巴特沃斯低通滤波器的优点,建立了一种新型超级电容器模型并验证了模型的准确性,这可以扩大超级电容器的适用范围,提高稳定性。     

Current mode first order universal filter and multiphase sinusoidal oscillator

In this article a new current mode first order universal filter with single input and multiple outputs is proposed. The realization uses single dual-X multiple output second generation current conveyor (DX-MOCCII) and two passive grounded components. The presented circuit provides high-pass, low-pass and non-inverting and inverting all-pass responses simultaneously, all at different high impedance outputs. The realized circuit does not require any component matching constraint and all the sensitivities are found low. As an application the non-inverting all-pass filter is cascaded in a close loop with the current mode non-inverting integrator to design a current mode multiphase sinusoidal oscillator (MSO) having six phases. Voltage mode six phase sinusoidal oscillator is also achieved by resistively loading the current mode outputs. The analysis such as phase noise, non-ideality, stability and Monte Carlo are presented and discussed. The presented theory and its results are validated using 0.25 µm process parameters of TSMC in PSPICE simulator.     

Third order lowpass Butterworth filter function realisation using CFA

A new realisation scheme for third order lowpass Butterworth filter function (BFF) using two CFA devices and few RC components is presented. The design equations utilise the transadmittance elements of the devices. The maximally flat response at select frequencies in the range 5 MHz ≤ f _o ≤ 30 MHz had been verified with PSPICE macromodel simulation and by hardware circuit implementation using the AD-844 device. The active sensitivities are quite low. The simulation result and the measured responses are included for f _o = 5.1 MHz and 22.2 MHz.     

切比雪夫低通滤波器的仿真设计

设计了一个切比雪夫低通滤波器,切比雪夫滤波器的通带内有纹波,阻带内衰减快,它是以通带内的波纹换取截止频率处的最大衰减。波纹越大,截止频率处的衰减越大。该设计方案能达到较好的滤波效果,并用电路仿真软件对其进行了仿真,仿真结果非常接近于理想滤波器的频率响应曲线。     

Compact microstrip low pass filter with flat group-delay using triangle-shaped resonators

In this paper, a compact microstrip lowpass filter (LPF) using triangle-shaped resonators is presented. The designed LPF includes three symmetric triangle-shaped resonators to provide a suitable passband and sharp response. A suppressing unit composed of several suppressing cells is designed to obtain a wide rejection band and low insertion loss in the passband. The fabricated LPF has been measured and indicts that it has −3 dB cut off frequency at 5.15 GHz. The rejection band has been expended from 5.51 GHz to 43.2 GHz with maximally flat return loss in this region nearby to 0 dB. Also, simulation and experimental results show that the proposed filter has a very flat group delay in the passband, which is the minimum value in comparison with the published works since 2017.     

PLL low pass filter design considering unified specification constraints

To appropriately configure the low pass filter (LPF) coefficients plays an important role in determining phase locked loop circuit performance. Most phase locked loop (PLL) design methods calculate LPF coefficients based on preselected loop bandwidth, phase margin, and then adjust LPF parameters to meet other specification requirements, i.e. locking time and phase noise. Such design approaches typically involve a number of iterative simulations, which are time consuming and are not very efficient. In this paper, we develop an analytical method to determine the allowable range of LPF coefficient values by considering unified PLL specification constraints. With the range identified, a clear guidance is obtained to facilitate LPF tuning and adaptive PLL design. For model validation, a charge pump PLL is designed and simulated using a 3rd party PLL simulation program—Cppsim.     

巴特沃斯低通滤波器在图像增强中的应用研究

频域图像增强是将图像通过变换函数从空域转换为频域,在频域空间里对图像进行滤波处理实现图像增强,再由逆变换函数转换回空域图像的过程.巴特沃斯滤波是频域滤波图像增强的一种.本文对图像增强知识、巴特沃斯滤波器及巴特沃斯低通滤波器算法的实现进行详细的介绍,通过在matlab中对原图和加噪图进行滤波仿真实验,分析实验结果,得出结...     

一种在时域调谐带通滤波器的新方法

文章介绍了一种基于滤波器S11响应的时域分析的调谐方法。这种方法可以区分谐振器和耦合孔各自产生的时域响应，可以用来指导调节谐振器和耦合系数，得到所需的滤波器响应。通过这种方法还可以观察滤波器内部各元件间是如何相互作用的。     

超短脉冲激光特性的三阶相关测量研究

在飞秒激光放大系统研制以及激光与物质相互作用研究过程中,良好的脉冲对比度是十分重要的一个指标,为了准确地测定激光对比度,我们利用非线性晶体对激光强度变化十分敏感的特性,研制了一台三阶相关仪,并对一台飞秒激光器进行了脉冲对比度的测量研究,所得结果揭示出了二阶相关仪所无法得到的信息,为测量飞秒激光脉冲的对比度提供了一种简便的方法.     

Nth order current mode universal filter using MOCCCIIs

This article presents a new current mode single-input-multiple-output nth order universal filter. The proposed circuit employs (n + 1) number multiple output second generation current conveyors and n number grounded capacitors only. Presented circuits can realize current mode low pass, high pass, band pass, notch and all pass responses simultaneously at different high output impedance terminals. The current mode filter circuit provides low input impedance by selecting the proper value of bias current and also has high output impedance, which is suitable for cascading. The circuit offers some important features such as resistor less realization, no passive component matching constraints, low sensitivity, electronic tunability and active-C realization. The functionality of the proposed filter circuit is tested with the PSPICE simulation, which is found to agree well with the proposed theory.     

Third order voltage mode universal filter using CCCII

This paper brings a multi input single output third order universal filter using second generation current controlled current conveyor (CCCII). The proposed structure consists of three CCCIIs and three capacitors for all filter responses. The universal filter offers all five sections of filter responses, namely: low-pass, high-pass, band-pass, notch filter and all-pass. The topology can provide all filter responses by the proper selection of input. The proposed universal filter offers some important features like no external resistor, minimum number of CCCIIs, no component matching constraint for filter response, electronically adjustable filter response using bias current of CCCIIs and many more. The workability of the proposed structure is well verified with PSPICE in which simulation results follow the theoretical one.     

表面肌电信号有源低通滤波器设计与验证

在运动康复治疗中,需要一种即能够滤除信号中的干扰,又能够放大信号的有源滤波器提取相关肌肉运动产生的表面肌电信号,以评估康复治疗效果。基于多重反馈型滤波器设计一种表面肌电信号的有源低通滤波器,并通过仿真进行验证。     

二阶有源低通滤波器设计与仿真研究

介绍了利用子系统的级联、反馈及电路仿真手段设计有源二阶滤波器简便方法。给出了电路参数选取的技巧。对反馈电路的接入点选择;系统传递函数的计算与验证都给出了详细的分析。仿真实验证明,通过调试可变电阻值,可以得到性能优良的二阶滤波器。     

R-FOG信号检测系统低通滤波器设计

设计了一种低截止频率、低FPGA资源占用率、高采样率的应用于谐振式光学陀螺 （Resonator Fiber Optic Gyro, R-FOG）数字信号检测系统中面向锁相放大器的低通数字滤波器。简化了滤波器的算法并进行了理论仿真和实验测试,结果表明该滤波器最低截止频率达到0.14Hz,采样率为40MHz,FPGA资源占用率降低至3%,阶数及截止频率调节方式操作简便,且幅频特性和相频特性优良。在谐振式光学陀螺信号检测系统中进行了测试,解调曲线零基准点稳定性明显提高。适用于以谐振式光学陀螺输出信号为代表的微弱信号检测系统。     

A low power Gm-C filter with on-chip automatic tuning for a WLAN transceiver

正A sixth-order Butterworth Gm-C low-pass filter(LPF) with a continuous tuning architecture has been implemented for a wireless LAN(WLAN) transceiver in 0.35μm CMOS technology.An interior node scaling technique has been applied directly to the LPF to improve the dynamic range and the structure of the LPF has been optimized to reduce both the die size and the current consumption.Measurement results show that the filter has 77.5 dB dynamic range,16.3 ns group delay variation,better than 3%cutoff frequency accuracy,and 0 dBm passband IIP3.The whole LPF with the tuning circuit dissipates only 1.42 mA(5 MHz cutoff frequency) or 2.81 mA(10 MHz cutoff frequency) from 2.85 V supply voltage,and only occupies 0.175 mm~2 die size.