Butterworth filter

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

A very small MMIC variable filter based on a new active filter design concept

Abstract: A novel MMIC (monolithic microwave IC) active filter is proposed for realizing a small-size variable bandpass filter with high selectivity at microwave frequencies. A second-order bandpass filter based on the proposed design concept occupies a 1.2*1.3 mm/sup 3/ area on the GaAs substrate. It is controllable for both quality factor Q, varying from 20 to 200, and a center frequency wider than 100 MHz at the 1.3 GHz band. A fourth-order bandpass filter was also fabricated by cascading two of the filter chips together. This is expected to be a key device in the future development of frequency-variable equipment. The design concept, fabrication, and measured performance of the filter are described. >

A Novel Log-Domain First-Order Multifunction Filter

Abstract: A new log-domain first-order multifunction filter is proposed in this letter. The proposed filter is systematically derived using the state-space synthesis procedure from a corresponding block diagram. It provides low-pass (LP), high-pass (HP), and all-pass (AP) responses simultaneously for a single input signal. The filter circuit has a very simple structure since it uses only bipolar junction transistors (BJTs) and a grounded capacitor. It can be electronically tuned by changing an external current. The filter has a greater bandwidth due to its inherent current-mode and log-domain operations. PSPICE simulations are given to confirm the theoretical analysis.

Explicit formulas for the synthesis of optimum bandpass Butterworth and Chebyshev impedance-matching networks

Abstract: Explicit formulas for computing the optimum design parameters of the bandpass impedance-matching networks having Butterworth and Chebyshev responses of arbitrary order for a class of most practical RLC load are derived It is shown that using at most a second-order all-pass function for the equalizer back-end reflection coefficient, a bandpass impedance match is possible if and only if the series inductance of the given load does not exceed a certain critical value This is in direct contrast to the low-pass situation where we showed earlier that any given RLC load can be matched using at most the rust-order all-pass function The significance of the present results is that we reduce the design of these practical bandpass impedance-matching networks to simple arithmetic

Design of 2-D Wideband Circularly Symmetric FIR Filters by Multiplierless High-Order Transformation

Abstract: In this paper, we modify the original McClellan transformation to a th-order version, and on the basis of the th-order McClellan transformation, we propose two high-order transformations for designing circularly symmetric wideband two-dimensional (2-D) digital FIR filter. The circularity of the resulting 2-D filters designed by our transformations is comparable to those 2-D filters designed by the other methods; however, the existing methods for circularly symmetric design cannot obtain a 2-D filter by the application of a single transformation on the 1-D filter response. By using the proposed transformations, in a single transformation on the 1-D filter, we can easily obtain the circularly symmetric 2-D digital FIR filter over a wide range of cutoff frequencies. Besides, with our approach, neither optimization procedure nor any computation is needed to obtain the transformation. Furthermore, since the implementations of the transformations are all multiplierless, the resulting 2-D filter has the same number of multipliers with the 1-D prototype filter. In the narrowband case, the 2-D transition width is shown to be narrower by a factor of about (and ) than the transition width of the 1-D prototype filter. This means that the filter length required in the prototype filter is shorter than that using the existing methods.