Topic
Butterworth filter
About: Butterworth filter is a research topic. Over the lifetime, 6187 publications have been published within this topic receiving 69070 citations.
Papers published on a yearly basis
Papers
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23 Dec 1981TL;DR: In this paper, a 5th order low-pass filter for connection in the voice signal path of a telephone subscriber line is described, where the filter characteristic in the pass band is substantially independent of the actual termination impedances of the filter in use.
Abstract: A filter comprising reactive components which define pass and stop bands has the impedances of the components selected to minimize the sum |Zin-Z2|+|Zout-Z1| in the pass band, where Zin and Zout are respectively the input and output impedances of the filter and Z1 and Z2 are nominal termination impedance at respectively the input and output of the filter. The filter characteristic in the pass band is thereby made substantially independent of the actual termination impedances of the filter in use. The design is exemplified by a 5th order low pass filter for connection in the voice signal path of a telephone subscriber line.
42 citations
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TL;DR: In this article, an explicit solution for the rational function P(z) for two classes of IIR orthogonal two-band wavelet bases, for which the scaling filter is maximally flat, is given.
Abstract: Explicit solutions are given for the rational function P(z) for two classes of IIR orthogonal two-band wavelet bases, for which the scaling filter is maximally flat. P(z) denotes the rational transfer function H(z)H(1/z), where H(z) is the (lowpass) scaling filter. The first is the class of solutions that are intermediate between the Daubechies (1992) and the Butterworth wavelets. It is found that the Daubechies, the Butterworth, and the intermediate solutions are unified by a single formula. The second is the class of scaling filters realizable as a parallel sum of two allpass filters (a particular case of which yields the class of symmetric IIR orthogonal wavelet bases). For this class, a closed-form solution is provided by the solution to an older problem in group delay approximation by digital allpole filters.
42 citations
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TL;DR: The bit-error-rate performance of narrowband digital FM with limiter-discriminator detection is considered for the cases of integrate and dump postdetection filtering with partial-bit integration, and sample-and-hold bit detection at the discriminator output.
Abstract: The bit-error-rate performance of narrowband digital FM with limiter-discriminator detection is considered for the cases of integrate and dump postdetection filtering with partial-bit integration, and sample-and-hold bit detection at the discriminator output. Error rate curves are presented for Gaussian, six-element Butterworth, and two-stage synchronously tuned IF filters. The calculations illustrate just how much more E/sub b//N/sub 0/ is required as the partial-bit integration time goes from 100% down to the limiting case of sample and hold. The results show that it is important to have a well-designed IF filter especially if the entire bit time is not available for detection. >
41 citations
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TL;DR: A new cost-function for an optimization algorithm to achieve a multiple passband filtering function has been introduced and a high-temperature superconductor ten-pole filter with triple-band performance has been designed and fabricated to verify this algorithm.
Abstract: The increasing demand on microwave spectrum for communication systems has been the driving force in the filter industry. Multiple filtering characteristics have become necessary for many filter designs in mobile and satellite applications. In this paper, a new cost-function for an optimization algorithm to achieve a multiple passband filtering function has been introduced. A high-temperature superconductor ten-pole filter with triple-band performance has been designed and fabricated to verify this algorithm. Each of the three passbands has a fractional bandwidth of approximately 0.26%.
41 citations
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TL;DR: In this paper, an improved hairpinline microstrip narrowband bandpass filter with via ground holes is presented, which reduces the size of the filter by 35% as compared to the conventional design.
Abstract: In this paper, we present a novel improved hairpinline microstrip narrowband bandpass filter with via ground holes. The new filter design methodology is derived from conventional hairpinline filter design. This design methodology incorporates use of λ/8 resonators, thereby reducing the size of the filter by 35% as compared to the conventional design. An analysis is presented to show the effects of tap point height and microstrip width on fundamental parameters of filter and subsequent relationships are developed. Through use of via ground holes and a wider microstrip line for resonators, 3 dB Fractional Bandwidth (FBW) less than 2%, Insertion Loss (IL) less than 1.6 dB and Return Loss (RL) better than 40 dB is achieved with midband center frequency 1 GHz. Spurious response suppression is achieved till 3f0. Robustness of this design approach is demonstrated by designing filters on two more substrates having er 2.17 and 9.2. As low as 0.48% FBW was achieved by using different substrates. The design approach is successfully tested for center frequency upto 2 GHz beyond which folding the resonator becomes practically difficult. Finally, a bandpass filter is designed with this design methodology and fabricated using FR4 substrate. S-parameter measurements show a good agreement with the simulated results.
41 citations