Butterworth filter

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

Analysis and optimization of noise in continuous-time OTA-C filters

Abstract: A general procedure is presented for noise analysis and optimization in continuous-time operational transconductance amplifier (OTA)-C filters of arbitrary order and topology. Based on a matrix description of a general OTA-C filter structure, universal expressions are derived that permit computing the filter noise and optimizing the noise performance in any OTA-C filter. The results are not only useful for classical (discrete or integrated) OTA-C designs at medium to high frequencies but also in modern radio-frequency integrated circuits (RFICs) by carefully replacing transistors or electronic subcircuits by OTA (macro) models. The formulas are easy to implement and are readily included in computer-aided analysis and optimization algorithms. The accuracy of the proposed algebraic method is confirmed by a comparison with SPICE-simulation results. Two application examples are given: Finding the minimum-noise a multiple-loop-feedback filter configuration to implement fifth-order Butterworth and Bessel transfer functions, and determining the optimal biquad sequencing and gain distribution in a cascade realization of an eighth-order Butterworth filter.

Analytical Diagnosis and Tuning of Narrowband Multicoupled Resonator Filters

Abstract: A novel analytical filter diagnosis technique based on the partial fraction expansions of admittance matrix is proposed in this paper. The technique is applicable to computer-aided filter tuning of a general Chebyshev filter. The key issue in the proposed technique is the extension of the realizability conditions to the asynchronously tuned filters for removing the phase-loading effect. Using this analytical diagnosis technique, the inherent dispersion effects of the resonators and coupling elements are compensated by removable stray couplings in the diagnosed filter models. The filter topology that can be handled by this technique is only limited by the availability of the exact filter synthesis technique with which the filter to be diagnosed is designed

An Equalized Ultra-Wideband Channel-Select Filter with a Discrete-Time Charge-Domain Band-Pass IIR Filter

Abstract: An ultra-wideband channel-select filter with equalized pass-band characteristics has been implemented with a 0.13 mum CMOS technology. A discrete-time charge-domain IIR band-pass filter is used to compensate degradation of the 3rd-order continuous-time LC-LPF and the sine response of the 1st-order charge-domain LPF, thus significantly equalizing the total filter response through clock signals. Measurements show that the IIR BPF reshapes the pass-band, allowing a 3-dB bandwidth of 500 MHz with a notch at 1 GHz. The total filter, including 3rd-order LC-LPF, 1st-order sine LPF, 1st-order IIR BPF, and clock generator, dissipates 18.8 mW from a 1.2-V supply voltage.

Maximally flat f.i.r. filter with prescribed cutoff frequency

Abstract: Maximally flat f.i.r. digital filter design provides the advantage of giving a closed-form solution, but there still remains a problem of designing such a filter whose magnitude response passes through a prescribed cutoff frequency point. It is described here how to generate a class of transitional maximally flat f.i.r. digital filters to overcome such a difficulty.