Butterworth filter

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

Numerical experiments with a new differentiation filter

Abstract: A dynamic programming filter which provides estimates of the first and second derivative of empirical displacement data is investigated numerically. This filter uses a weighted least squares criteria in estimating the derivatives. The filter equations are presented together with several numerical examples. These examples are taken from references that proposed other techniques.

Mixed-mode universal filter using MCCCII

Abstract: A novel mixed-mode biquad filter based on MCCCIIs (multiple outputs current controlled conveyors) is presented The filter structure presented simply contains five MCCCIIs, two grounded capacitors and can realize low-pass, high-pass, band-pass filter functions from the same topology, simultaneously The circuit can be driven by voltage or current and its output can be voltage or current The natural frequency ω 0 and quality factor Q enjoy independent electronic tunability through adjusting the bias currents of MCCCIIs Simulation results using real device parameters of transistors NR100N and PR100N are included to show the practical utility of the proposed circuit

A new miniature Peano fractal-based bandpass filter design with 2nd harmonic suppression

Abstract: A new compact microstrip bandpass filter design is presented in this paper as a candidate for use in modern wireless communication systems. The proposed filter structure is composed of two fractal-based microstrip resonators. The structure of each resonator is in the form of the 3rd iteration Peano fractal curve. The resulting filter structure based on these resonators, shows a considerable size reduction compared with the other microstrip bandpass filters based on other space-filling geometries designed at the same frequency. A second bandpass filter design based on the same resonator but with a tuning stub has been also presented, in an attempt to provide practically useful means to tune the filter to the specified performance with a considerable tuning range. The performance of the resulting filter structures has been evaluated using a method of moments (MoM) based electromagnetic simulator IE3D, from Zeland Software Inc. Results show that the proposed filter structures possess good return loss and transmission responses besides the size reduction gained, making them suitable for use in a wide variety of wireless communication applications. Furthermore, performance responses show that the second filter, based on Peano shaped resonator with stub, has less tendency to support the 2nd harmonic.

Adjustable electronic tunable filter with simulated inductor

Abstract: A stable tunable Q bandpass filter adapted to have its parameters dynamically varied over a wide range of bandwidths and center frequencies. The filter includes a capacitor and a network coupled in parallel across the capacitor. The network includes a plurality of operational amplifiers coupled to simulate an inductor without utilizing coils. A feature of the filter is that it can be readily made adaptive to track an input signal which may randomly vary in frequency. A further feature of the invention is to have one input of each operational amplifier coupled directly to ground to minimize stray capacitance. The performance characteristics of this filter are in part attained by the method of component layout and shielding techniques used, in addition to the method of circuit excitation.

Multi-passband dielectric filter construction having filter portions with dissimilarly-sized resonators

Abstract: A filter duplexer, such as a filter duplexer for a radio transceiver, of minimum dimensions is disclosed. A first filter portion of the duplexer filter includes resonators of a first geometric configuration, and a second filter circuit portion of the duplexer filter comprises resonators of a second geometric configuration. The geometric configuration of the two filter circuit portions are dissimilar such that relative characteristic admittances of the resonators of the respective filter circuit portions are dissimilar. Because the resonators of the two filter circuit portions are of dissimilar electrical characteristics, a desired frequency response of the duplexer filter may be obtained with similar resonator loading capacitances.