Butterworth filter

About: Butterworth filter is a research topic. Over the lifetime, 6187 publications have been published within this topic receiving 69070 citations.

Implementation of a Dynamic Voltage Restorer System Based on Discrete Wavelet Transforms

Abstract: This paper presents an implementation of the discrete wavelet transform (DWT) using passive LC filters for operating a dynamic voltage restorer (DVR) system. The proposed implementation is based on designing Butterworth passive LC filters with cutoff frequencies that are identical to cutoff frequencies of DWT associated digital filters. These passive LC filters can detect abnormal conditions that may disrupt the quality of the power supplied to sensitive loads in a power system. Detecting any abnormal condition is realized through extracting high- and low-frequency components present in system voltages using high-pass and low-pass filters, respectively. The designed Butterworth passive LC passive filters are third-order systems to simplify their practical implementation as well as their integration with the test power system and the DVR. Simulation and experimental test results for transient voltage dip and steady-state harmonic distortion cases show significant performance improvement of the DVR system operated by the designed Butterworth passive LC filters. The proposed DWT-operated DVR system using Butterworth passive LC filters is implemented and tested for improving the power quality under different abnormal conditions.

A New Second-Order All-Pass Filter in 130-nm CMOS

Abstract: This brief presents a novel wide-bandwidth second-order voltage-mode all-pass filter derived from a canonical single transistor bandpass filter. The core of the circuit consists of only one transistor, two resistors, and two energy storage elements. The operation of the proposed filter is validated experimentally. A filter implemented in an IBM 0.13- $\mu\mbox{m}$ CMOS was measured to have a 55-ps group delay across a 6-GHz bandwidth while consuming 18.5 mW from a 1.5-V supply. This work experimentally demonstrates a CMOS all-pass filter that operates at multigigahertz frequencies and achieves the highest delay-bandwidth product compared to previously published CMOS all-pass filters known to the authors.

Synthesis of ultra-wideband bandpass filter employing parallel-coupled stepped-impedance resonators

Abstract: To design an ultra-wideband (UWB) bandpass filter with the fractional bandwidth (FBW) up to 110% (31%106%GHz), a new filter prototype consisting of multi-stage parallel-coupled stepped-impedance resonators (SIRs) is synthesised based on the transmission-line theory rather than the conventional multi-mode property Asymmetrical SIRs are employed instead of the conventional symmetrical/quasi-symmetrical ones, so that an extra degree of freedom is introduced in circuit parameter selection As a result, the minimum dimension of the coupling gaps between the adjacent SIRs is successfully enlarged to be more than 01%mm, which alleviates the requirement on fabrication precision A simple equivalent circuit for this filter prototype is represented in the form of distributed parameters and the corresponding Chebyshev filtering function is derived as well The relation between the number of poles in passband, N p , and the stage of the filter, n , is summarised to be N p =3 n +2 To validate the newly derived synthesis theory, a one-stage UWB filter is first synthesised to compare with the previously published results obtained by the electromagnetic (EM) simulator Furthermore, a two-stage filter is synthesised to successfully meet the Federal Communications Commission (FCC)+s indoor/outdoor spectrum specifications The fabricated UWB filter exhibits a compact size of 2658+mm in total length, low insertion loss (09+dB at 685+GHz), flat group delay (05+01+ns), good stopband characteristics (+S21+++40+dB at 1+2+GHz) and steep skirt property (+28+dB/GHz) as well It should be noted that the proposed filter prototype can be also used to realise aUWB filter with an FBW even greater than 110+

A SU8 Micromachined WR-1.5 Band Waveguide Filter

Abstract: A WR-1.5 band (500-750 GHz) waveguide 3rd order bandpass filter has been designed, fabricated, using SU8 photoresist technology, tested and presented. The filter is composed of three silver-coated SU8 layers, each of the same nominal thickness of 191 μm. This filter structure is based on three offset resonators. This novel structure is ideally suitable for the layered SU8 micromachining process. The filter exhibits a 53.7 GHz 3-dB bandwidth at a central frequency of 671 GHz. The median passband insertion loss is measured to be 0.65 dB and the return loss is better than 11 dB over the whole passband.

Low-Noise Low-Pass Filter for ECG Portable Detection Systems with Digitally Programmable Range

Abstract: This paper presents the design of an operational transconductance amplifier-C (OTA-C) low-pass filter for a portable Electrocardiogram (ECG) detection system. A fifth-order Butterworth filter using ladder topology is utilized to reduce the effect of component tolerance and to provide a maximally flat response. The proposed filter is based on a novel class AB digitally programmable fully differential OTA circuit. Based on this, PSPICE simulation results for the filter using 0.25-μm technology and operating under ±0.8 V voltage supply are also given. The filter provides a third harmonic distortion (HD3) of 53.5 dB for 100 mV p-p @50 Hz sinusoidal input, input referred noise spectral density of , total power consumption of 30 μW, and a bandwidth of 243 Hz. These results demonstrate the ability of the filter to be used for ECG signal filtering that is located within 150 Hz.