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Showing papers on "Butterworth filter published in 1970"


Journal ArticleDOI
TL;DR: In this paper, an improved underdamped LCR filter with an oscillatory or non-oscillatory response to a step change of the input voltage is presented. And the frequency response and the time response for a unit step of a normalized improved filter for various degrees of damping.
Abstract: The majority of high-current dc power supplies for beam bending magnets have well known LCR low-pass ripple filters. To avoid prohibitive heat losses, the filter damping resistor is in series with the capacitor and not in the dc path. Such filters, when critically damped, attenuate high frequencies by 6 dB/octave. This paper analyzes an improved underdamped LCR filter which attenuates high frequencies by 12 dB/octave. Depending on the application, the improved filter can be designed to have an oscillatory or a non-oscillatory response to a step change of the input voltage. Design curves are given which show the frequency response and the time response to a unit step of a normalized improved filter for various degrees of damping.

39 citations


Patent
26 May 1970
TL;DR: In this paper, an automatic tracking filter for use in conjunction with fluid flowmeters automatically locks onto the largest signal in a given frequency spectrum, which is a narrow band-pass filter having input and output filter circuits (e.g., a low pass and a high pass filter) connected in series.
Abstract: An automatic tracking filter for use in conjunction with fluid flowmeters automatically locks onto the largest signal in a given frequency spectrum. The filter comprises a narrow band-pass filter having input and output filter circuits (e.g., a low-pass and a high-pass filter) connected in series. The output of the input filter circuit is combined in a control circuit with the input signal to generate an error signal which is used to tune each of the filter circuits to the input signal. In one embodiment disclosed the filter sections are two-pole active R-C filters in which a field-effect transistor is used as a voltage variable resistor.

38 citations


Patent
28 May 1970
TL;DR: In this paper, a transversal filter is used to convert a first time function applied to the filter input into a second time function at the filter output, which is then converted into the time domain inpulse response of the filter.
Abstract: A system for utilizing a single pulse having initially known characteristics to set the tap weights of a transversal filter to convert a first time function applied to the filter input into a second time function at the filter output. The pulse as it appears at the system input is converted into a first representation in the frequency domain and is mathematically operated upon, in conjunction with a generated second representation in the frequency domain of the pulse as it is desired that it appear at the output from the filter, to generate the frequency domain transfer function of the transversal filter. This transfer function is then converted into the time domain inpulse response of the filter which may be directly utilized to form the desired set of weighting factors for the transversal filter. When the first time function is a signal received over a transmission media, the system may function as a media equalizer.

21 citations


Journal ArticleDOI
TL;DR: In this paper, the noise bandwidth of Butterworth, Bessel, and Chebyshev filters is tabulated, and it is proven that B N is invariant when a low-pass to bandpass transformation is made.
Abstract: The noise bandwidth B N of Butterworth, Bessel, and Chebyshev filters is tabulated. The Butterworth filter is shown to have the minimum B N to 3-dB bandwidth ratio for any secondorder filter. It is proven that B N is invariant when a low-pass to bandpass transformation is made. An error is corrected in recent tables of Chebyshev filters.

17 citations


Patent
22 Jun 1970
TL;DR: In this article, the authors propose a digital filter multiplier network, in which a set of weighting signal samples to be multiplied in the filter has values which are exactly powers of two such that the filter multiplier networks may be comprised of simple signal routing circuits.
Abstract: Digital filter apparatus in which a set of weighting signal samples to be multiplied in the filter has values which are exactly powers of two such that the filter multiplier network may be comprised of simple signal routing circuits

11 citations



Patent
10 Dec 1970
TL;DR: In this paper, a phase-locked tracking filter is described, in which the input and output voltages of a band-pass filter are compared as to phase and a control voltage produced to vary the characteristics of the filter to force the filtering to ''''track'''' and provide maximum noise rejection of a desired input frequency.
Abstract: A phase-locked tracking filter in which the input and output voltages of a band-pass filter are compared as to phase and a control voltage produced to vary the characteristics of the filter to force the filter to ''''track'''' and provide maximum noise rejection of a desired input frequency. The phase comparison and feedback means includes, in the preferred version of the invention, inverting and non-inverting Schmitt triggers, a monostable multivibrator and a flip-flop phase-sensitive detector to provide a square wave voltage whose mean DC value is related to the phase difference. This voltage is used to control and vary the characteristics of the band-pass filter.

6 citations


Journal ArticleDOI
01 Feb 1970
TL;DR: In this article, an active realization for a low-pass maximally flat linear amplitude filter is presented, which displays a linear amplitude rise, band-limited differentiation, with increasing frequency out to a cutoff frequency at which point the response falls off at a rate determined by the order of the filter.
Abstract: An active realization for a low-pass maximally flat linear amplitude filter is presented. The filter displays a linear amplitude rise, band-limited differentiation, with increasing frequency out to a cutoff frequency at which point the response falls off at a rate determined by the order of the filter.

4 citations


Journal ArticleDOI
Toby Gilsig1
TL;DR: A simple three-phase filter connection that can significantly reduce losses for high-power applications without automatic tuning is presented and it is shown that the fundamental-frequency power losses can, for some cases, be limited to those associated with the filter inductors and capacitors.
Abstract: A simple three-phase filter connection that can significantly reduce losses for high-power applications without automatic tuning is presented. It is shown that the fundamental-frequency power losses can, for some cases, be limited to those associated with the filter inductors and capacitors. Perfornance equations for the filter at the fundamental frequency and at resonance are derived, and an example is given.

3 citations


Journal ArticleDOI
01 Jan 1970
TL;DR: The second order compensator filter is introduced at low rate in order to improve the passband of interest of the overall filter and exhibits a high attenuation in the stopband, as well as a low passband droop.
Abstract: This paper presents efficient modification of the CICcosine decimation filter. The second order compensator filter is introduced at low rate in order to improve the passband of interest of the overall filter. The coefficients of the compensator filter are presented in a canonical signed digits (CSD) form, and can be implemented using only adders and shifts. Consequently, the resulting filter is a multiplierfree filter and exhibits a high attenuation in the stopband, as well as a low passband droop.

2 citations


Journal ArticleDOI
TL;DR: Design procedures, possibilities for filter grouping and experimental results with Linear Phase and Butterworth filters are presented.
Abstract: Linear phase 10.7 MHZ IF amplifier filters can offer many advantages such as lower and improved stereo multiplex performance over tose having a rectangular response characteristic. Design procedures, possibilities for filter grouping and experimental results with Linear Phase and Butterworth filters are presented. Designs are oriented toward using readily available low cost components.


Journal ArticleDOI
01 Jun 1970
TL;DR: In this article, a modified filter system based on Butterworth polynomials is suggested and the transient and frequency response reported, and the combined signal at the output of the combined filter is not identical to the input.
Abstract: The constant input impedance properties of combined high- and low-pass Butterworth filters would make them appear ideal for loudspeaker crossover networks. However, the combined signal at the output of the combined filter is not identical to the input. A modified filter system based on Butterworth polynomials is suggested and the transient and frequency response reported.