Topic
Butterworth filter
About: Butterworth filter is a research topic. Over the lifetime, 6187 publications have been published within this topic receiving 69070 citations.
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Papers
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TL;DR: Maximum Entropy Spectral Analysis (MESA) has proven itself excellent in all regards and is compared here to other common techniques.
Abstract: There is an array of numerical techniques available to estimate the period of circadian and other biological rhythms. Criteria for choosing a method include accuracy of period measurement, resolution of signal embedded in noise or of multiple periodicities, and sensitivity to the presence of weak rhythms and robustness in the presence of stochastic noise. Maximum Entropy Spectral Analysis (MESA) has proven itself excellent in all regards. The MESA algorithm fits an autoregressive model to the data and extracts the spectrum from its coefficients. Entropy in this context refers to “ignorance” of the data and since this is formally maximized, no unwarranted assumptions are made. Computationally, the coefficients are calculated efficiently by solution of the Yule-Walker equations in an iterative algorithm. MESA is compared here to other common techniques. It is normal to remove high frequency noise from time series using digital filters before analysis. The Butterworth filter is demonstrated here and a danger inherent in multiple filtering passes is discussed.
21 citations
TL;DR: The classical filters were compared with the wavelet shrinkage and Satisfying similarity to reference signal was observed in the case of Butterworth filter, Savitzky-Golay smoothing, ADPF filter, Fourier denoising and soft-thresholded waveletshrinkage with any mother wavelet and middle to high decomposition level.
21 citations
TL;DR: In this article, a resistorless wave active filter using voltage differencing transconductance amplifier is presented, which uses grounded capacitor and also possesses electronic tunability of cut-off frequency via bias current.
Abstract: This paper presents a systematic approach for the realization of resistorless wave active filter using voltage differencing transconductance amplifier. The proposed filter uses grounded capacitor and also possesses electronic tunability of cut-off frequency via bias current. The functionality of the proposed filter is verified for a 4th order low pass filter through PSPICE simulation using 0.18 µm TSMC CMOS technology parameter. Experimental results using commercially available IC LM13700/NS are also included which corroborate the theoretical and simulated results.
21 citations
TL;DR: In this article, a compact ultra wideband band-pass filter with low insertion loss and good rejection using semi complementary split ring resonator is introduced, which can be used as conventional microstrip filters in commercial and military RF boards.
Abstract: In this contribution, a compact ultra wideband band-pass filter with low insertion loss and good rejection using semi complementary split ring resonator is introduced. The 3.0 dB bandwidth is 2.9–8.2 GHz. The minimum and maximum insertion losses in passband are about 0.35 and 1.4 dB at frequencies of 5.4 GHz and 4 GHz respectively in measurement. The bandwidth is tunable via changing the upper 1.0 dB cutoff frequency from 5.0 to 9.0 GHz. The dimensions of this filter (excluding access line for connectors) are about 7.2 × 7.2 mm2. The proposed filter is classified in DGS filters group without their problems such as radiation fields from DGS and requiring specific box. In addition, this filter can be used as conventional microstrip filters in commercial and military RF boards. Low-loss and compact behaviors in most frequency of pass-band are interpreted due to the presence of simultaneously negative eeff and μeff , and then left-handed wave propagation is permitted.
21 citations
01 Jan 2005
TL;DR: In this article, a synthesis theory of bandpass filters with modified Butterworth-Chebyshev (BC) or Chebysheve-Chebychev frequency response is proposed, where composite resonators are employed to produce transmission zeros in order to get sharp attenuations of the filter.
Abstract: A synthesis theory of bandpass filters (BPFs) with modified Butterworth-Chebyshev or Chebyshev-Chebyshev frequency response is proposed. Instead of using cross-couplings between non-adjacent resonators, composite resonators are employed to produce transmission zeros in order to get sharp attenuations of the filter. The filter has as many transmission zeros in both its lower and upper stopbands as the number of resonators it used. The theory is developed based on the well-know lumped-element equivalent circuit of a BPF. Therefore, the classical design equations remain valid provided a few new formulas are supplemented. An easy realization method of the filter using microstrip lines is described, and 2-degree and 3-degree example filters with modified Chebyshev-Chebyshev response are designed. The measured filter characteristics agree excellently with the theoretical predictions.
21 citations