Butterworth filter

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

A 240-MHz Low-Pass Filter With Variable Gain in 65-nm CMOS for a UWB Radio Receiver

Abstract: An integrated fifth-order continuous-time low-pass filter for a WiMedia ultrawideband radio receiver is described in this paper. The prototype filter is realized with a passive pole at the filter input and a fourth-order leapfrog filter in which the gm-C technique with pseudodifferential transconductors is used. The transconductors do not include internal nodes, and they are designed to have a nominal 26-dB dc gain, of which process, voltage, and temperature variations are controlled by means of a negative resistance circuit. The losses of the low-dc-gain filter integrators are already taken into account in the filter synthesis. The passband edge frequency of the implemented filter is 240 MHz in order to receive multiband-orthogonal-frequency-division-multiplexing signals using the direct-conversion topology. The voltage gain of the filter can be controlled from 9 to 43 dB in the 1-dB gain steps. The filter achieves a 7.8-nVradicHz input-referred noise density, a -8-dBV out-of-band third-order intermodulation intercept point, and a +15-dBV out-of-band second-order intermodulation intercept point. The circuit uses a 1.2-V supply and has been fabricated in a modern 65-nm CMOS technology.

Damped input filter design of matrix converter

Abstract: This paper deals with the input filter design of matrix converter Regard the matrix converter as a buck type PWM rectifier in the input side, the transfer function of input current using LC input filter is deduced The parameter selection approach for the capacitor and inductor is presented It has been verified that when LC circuit is adopted in the input filter, the input current will oscillate near the LC resonant frequency in both steady state and start-up process for the very low damping factor, and then the input current waveforms will be distorted An improved input filter topology to increase the damping factor is then presented, and the damping resistance parameter selection method of the input filter is presented based on frequency response approach To avoid the current spike at the start-up process, a start-up circuit is then proposed The improved input filter has been tested on a 55kW matrix converter prototype and good performances are achieved

Effects of reconstruction filters in digital predistortion linearizers for RF power amplifiers

Abstract: The reconstruction filters are a major source of error in digital predistortion linearizers for RF power amplifiers. This paper presents a method that enables these filters to be designed for lowest filter complexity and minimum degradation of the linearizer performance. Furthermore, a method to choose an appropriate sampling rate for the predistorter is presented. Different filter approximations and orders are examined for different amplifier configurations by means of simulation. Of the filters tried, low-ripple Chebyshev and Butterworth filters perform best. It is demonstrated that it is possible to account for reasonable filter misalignment with only a small degradation in performance. It is also shown that the effect on the modulation is small with respect to intersymbol interference. >

Command filtered adaptive fuzzy backstepping control method of uncertain non-linear systems

Abstract: The command filtered adaptive fuzzy backstepping control method has been proposed in this study. By using the command filter, it is not only the states, the actuator constraints, and the problem of ‘explosion of complexity’ in conventional backstepping have been solved, but also the calculation of partial derivatives is unnecessary, so that control law and update law become succinct. Fuzzy logic systems, designed in this study, are utilised in real-time identification of the uncertain non-linear functions. Throughout the process of controller design, the transformed style and Butterworth low-pass filter are applied to solve the problem of unknown control directions. Using the Lyapunov theorem, it has been shown that the approach can guarantee all the signals of the resulting closed-loop system are semi-globally uniformly ultimately bounded. Finally, an application of the method has been made to the controller design of the attack angle of a hypersonic vehicle. The simulation results are given to prove the effectiveness of the method presented in this study.

Insensitive current-mode universal filter using dual output current conveyors

Abstract: A new current-mode universal filter with single input and three outputs employing only three dual output current conveyors and five grounded passive elements is presented. The proposed filter realizes three filter functions simultaneously, all at high impedance outputs. No component matching is required and all the passive and active sensitivities are low. Furthermore, the filter can also realize the notch and all-pass responses. Orthogonal control of the natural angular frequency and the quality factor is achieved.