Active High-pass Filter Research Articles

On an Active High-Pass Network with Equal Capacitors

This short article fills up a gap in a previous publication on the design of an active Butterworth high-pass filter employing equal capacitors.

Design and Simulation of Low Dropout, Low Power Capless Linear Voltage Regulator

This paper demonstrates a low power, frequency compensated with on-chip capacitor, low dropout linear voltage regulator. The proposed low dropout regulator (LDO) delivers a constant output voltage of 2.4[Formula: see text]V for an input range of 2.5–6.8[Formula: see text]V. A minimal drop of 2[Formula: see text]mV and 20[Formula: see text]mV was observed at no load and full load output current of 0 A to 100[Formula: see text]mA, respectively. LDO is realized by a high-gain two-stage error amplifier, internally compensated by passive a high-pass filter to achieve stability over a load current range of 0–100[Formula: see text]mA without occupying as much area as an active high-pass filter. The LDO presented requires a bias current of 10[Formula: see text]mA with a reference voltage of 1.5[Formula: see text]V and is designed in 180-nm technology.

Active Integral High Pass Filters

Active Integral High Pass Filters

Numerical Analysis of Filtering Circuit for Partial Discharges

Partial Discharge (PD) is a small electrical spark that happens within the insulation of medium and high voltage electrical assets. It is important to note that the discharge will erode the insulation and eventually result in disastrous insulation failure. Thus, PD detection is a crucial issue in high voltage insulation area. However, the on-site field PD tests, the high frequency PD signals detected by sensors, are vulnerable to interferences and background noises. This has a negative effect on high voltage apparatus fault diagnosis and localization accuracy. For that reason, noise suppression has become an urgent and vital issue for field high frequency PD signal testing. Thus, this research aims to model a filtering circuit to suppress the noise along with PD in high frequency measurement. A filtering circuit was analysed by using Proteus software to filter out the noise along with PD with decent accuracy and efficiency. Then, performance investigation of active high pass and passive high pass was conducted and studies to filter out PD noise suppression in high frequency were successfully developed. The active filter was focusing on the first order stage until fourth order stage. The passive filter only concentrated on two types of order stage; first order stage and second order stage. The result demonstrated that active high pass filter presented the best performance with low decibel frequency response (-20 dB), and was suitable for this research purpose compared to passive high pass filter. Besides, 700 Vrms has been selected to check the response at high voltages and the frequency values set at 50 Hz for low frequency and 8 kHz for high frequency. This specification design values have been selected because it is suitable for situations in high-tension power line. This type of filtering circuit is suitable to be used for academic and lab experimentation.

Memristor Modeling Using the Modified Nodal Analysis Approach

The memristor has long been presented as the fourth fundamental circuit element alongside the resistor, the capacitor, and the inductor. As the future of computing heads toward neuromorphic circuits, there has been a renewed interest in the modeling and simulation of memristors which have emerged as promising key components in the design of these systems. Despite such critical applications, very few models have been presented in the literature that allow for the automated and flexible integration of memristors in different simulators. In this article, three different models of the memristor are presented using the modified nodal analysis (MNA) formulation technique. Each stamp is tested and compared with a theoretical model of the memristor. Simulations are also performed on a memristor-based active high-pass filter circuit to demonstrate the accuracy of the model.

Design of Active Vibration Reduction System for Intelligent Ship Mechanical Equipment

Li, B. and, Yang, H., 2020. Design of active vibration reduction system for intelligent ship mechanical equipment. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 235-237. Coconut Creek (Florida), ISSN 0749-0208.An intelligent shock absorber with active-passive compound and integrated sensing action is developed for engineering needs. It's based on the traditional passive isolation structure, the active actuator, power amplifier, high and low pass filter, acceleration error sensor and subsequent amplifier and filter circuits are integrated. An active damping system for ship machinery equipment is constructed with an active controller running offline. Based on the system, a demonstration platform for active vibration reduction of diesel generator set is established. The entire bench is mounted on an elastic steel plate simulating the hull structure through four intelligent shock absorbers, the vibration performance of the active vibration reduction system is evaluated by measuring the vibration of the elastic steel plate. The demonstration bench test results show that The total vibration level of the intelligent shock absorber within 800 Hz has a passive vibration reduction effect of more than 33 dB, Based on this, active control has a good control effect on multiple lines within 200 Hz, A maximum active attenuation of 30.8 dB, The active attenuation of total vibration level within 200Hz reaches 20 dB.. Synthesizing the effects of active and passive vibration reduction, the intelligent shock absorber can attenuate the total vibration level of the diesel generator set of the demonstration bench O∼ more than 47.2 dB in the range of 800 Hz.

Binary memcapacitor based first-order active filter

Purpose The purpose of this paper is to construct a flux-controlled memcapacitor (MC) emulator without grounded restriction with the binary operation ability. The active first-order low-pass filter (LPF) and high-pass filter (HPF) circuits are constructed by replacing the capacitor with MC. Design/methodology/approach The output saturation of the active device is innovatively adopted to realize the binary operation of MC with two memcapacitance values. By applying the direct current control voltage together with the input signal, the memcapacitance can be controlled, and hence, cut-off frequency of the filters can be adjusted without changing the circuit structure. Findings Experiments and simulation results show that the new filter has good frequency selectivity. Both LPF and HPF can change the cut-off frequency by changing the positive and negative control voltage. The experimental and simulation results are in good agreement with the theoretical analysis, which proves the feasibility and validity of the emulator and the filters. Originality/value These MC emulators are simple and easy to physically fabricate, which have been increasingly used for experiment. It also provide an effective reference for device miniaturization and low power consumption.

Generating Multi-Scroll Chua’s Attractors via Simplified Piecewise-Linear Chua’s Diode

High implementation complexity of multi-scroll circuit is a bottleneck problem in real chaos-based communication. Especially, in multi-scroll Chua's circuit, the simplified implementation of piecewise-linear resistors with multiple segments is difficult due to their intricate irregular breakpoints and slopes. To solve the challenge, this paper presents a systematic scheme for synthesizing a Chua's diode with multi-segment piecewise-linearity, which is achieved by cascading even-numbered passive nonlinear resistors with odd-numbered ones via a negative impedance converter. The traditional voltage mode op-amps are used to implement nonlinear resistors. As no extra DC bias voltage is employed, the scheme can be implemented by much simpler circuits. The voltage-current characteristics of the obtained Chua's diode are analyzed theoretically and verified by numerical simulations. Using the Chua's diode and a second-order active Sallen-Key high-pass filter, a new inductor-free Chua's circuit is then constructed to generate multi-scroll chaotic attractors. Different number of scrolls can be generated by changing the number of passive nonlinear resistor cells or adjusting two coupling parameters. Besides, the system can be scaled by using different power supplies, satisfying the low-voltage low-power requirement of integrated circuit design. The circuit simulations and hardware experiments both confirmed the feasibility of the designed system.

A design of readout IC with capacitively-coupled chopper current-feedback instrumentation amplifier in a 0.18 μm CMOS process

This paper describes a readout IC (ROIC), which consists of a capacitively coupled instrumentation amplifier (CCIA) and a discrete-time delta–sigma modulator. An active high-pass filter is embedded in the ripple reduction loop to suppress the noise ripple amplitude due to chop modulation. To accommodate the input with large electrode offset, dc-servo loop (DSL) and a 6 bit capacitive DAC are employed to suppress large electrode offset, while a positive feedback loop to boost its input impedance. The complete CCIA is implemented in a standard 0.18 μm 1P6M CMOS process. It occupies an area of 0.56 mm2 (including DSL) and consumes 52 μA current from a 3.3 V supply voltage. Measurement results indicate that the input reference noise PSD is 53.8 nV√Hz.

THE MECHANICAL QUANTITIES TRANSDUCERS EVOLUTION WITH THE DOMAIN-DISSIPATIVE PIEZOELECTRIC CELLS IN THE CHARTS OF THE ACTIVE HIGH-PASS FILTER

The article suggested the equivalent circuit of the inverter mechanical values with piezoelement in the scheme of the active high-pass filter with multi-loop feedback. The frequency converters transmission ratio is received. The modeling and study of the frequency response of piezoelectric transducers using computer modeling in MS9 package where performed. This bimorph according to the theory of electromechanical analogies presented by series-parallel oscillating RLC - circuit. The correspondence of computer and mathematical model of the converter real converter, which is confirmed by the coincidence of the frequency and characteristics of the amplitude. The information generated by a computer model of the frequency response transducers match the frequency response, and based on mathematical models. It was established that the non-linearity of frequency and amplitude-frequency error transducers depends on the angle between the polarization vector and the vector of the electric field of the output voltage. For drives on the basis of the modified active filter circuits treble with an increase in the angle between the polarization vector and the vector of the electric field of the output voltage from 0 to 82˚ resonant peak of the converter and the amplitude-frequency error is reduced

A 2- 45-nV/√Hz Readout Front End With Multiple-Chopping Active-High-Pass Ripple Reduction Loop and Pseudofeedback DC Servo Loop

This brief presents an ultra-low-power low-noise chopped capacitively coupled instrumentation amplifier (CCIA) that is suitable for neural recording applications. An active high-pass filter is embedded in the ripple reduction loop (RRL) to suppress the residual noise and relax the capacitor size. Multiple chopping is employed to further reduce the residual output ripple due to the RRL offsets. A dc servo loop (DSL) using a 14-nA pseudofeedback amplifier is proposed to achieve a subhertz high-pass corner while using only a 15-pF on-chip capacitor. The complete CCIA is implemented in a standard 0.18- $\mu\text{m}$ CMOS process. It occupies an area of 0.23 mm2 (including the DSL) and consumes 1.7 $\mu\text{A}$ from a 1.25-V supply, achieving a noise efficiency factor of 2.9 that compares favorably with the state of the art.

Light-Activated Amplification in Si-C Tandem Devices: A Capacitive Active Filter Model

Characteristics of tunable wavelength pi'n/pin filters based on a-SiC:H multilayered stacked cells are studied both experimentally and theoretically. Results show that the device combines the demultiplexing operation with the simultaneous photodetection and self amplification of the signal. An algorithm to decode the multiplex signal is established. A capacitive active band-pass filter model is presented and supported by an electrical simulation of the state variable filter circuit. Experimental and simulated results show that the device acts as a state variable filter. It combines the properties of active high-pass and low-pass filter sections into a capacitive active band-pass filter using a changing capacitance to control the power delivered to the load.

Self optical gain in multilayered silicon-carbon heterostructures: A capacitive active band-pass filter model

ABSTRACTThis paper reports results on the use of a pi’n/pin a-SiC:H heterostructure as an active band-pass filter transfer function whose operation depends on the wavelength of the trigger light, on the applied voltage and on the wavelength of the additional optical bias.Results show that the device combines the demultiplexing operation with the simultaneous photodetection and self amplification of the signal. Experimental and simulated results show that the output signal has a strong nonlinear dependence on the light absorption profile. The device, modeled by a simple circuit with variable capacitors and interconnected phototransistors through a resistor, is a current-controlled device. It uses a changing capacitance to control the power delivered to the load acting as a state variable filter circuit. It combines the properties of active high-pass and low-pass filter sections into a capacitive active band-pass filter.

Equalization and near-end crosstalk (NEXT) noise cancellation for 20-Gb/s 4-PAM backplane serial I/O interconnections

Limitations in current backplane environments impede high-speed data transmission above 5 Gb/s. A system architecture to extend the transmission capacities of legacy backplanes is proposed. The incentives for using a four-level pulse amplitude modulation (4-PAM) scheme are also presented. The architecture is built from feed-forward equalizer and tunable filter elements for near-end crosstalk noise cancellation. Each of the circuits is implemented in a standard 0.18-/spl mu/m CMOS process. The building blocks of the architecture, which include an LC ladder, a modified Gilbert-cell multiplier with improved headroom, and a tunable active high-pass filter are described in detail. Results of the architecture are shown demonstrating 20-Gb/s 4-PAM signal transmission.

The Determination of a Blood-flow Parameter by the Doppler Method

Skin measurements made using the Doppler method can be used to monitor blood flow and involuntary body movements. The spectra of the Doppler signal indicate that it is dominated by the involuntary body movements and that the blood flow is detectable only at higher frequencies. Some separation of the two signals is therefore possible if an active high-pass filter is used. By this means the blood-flow parameter has been measured during artificial variations of the blood flow and at different parts of the body. A special arrangement of optical fibres allows the scattered light and its mean intensity at the same location to be detected separately. The influence of intensity variations is compensated without using any time constant.

A single-chip CMOS analog front-end for high-speed modems

A single-chip analog front-end for high-speed modems has been developed in 5μ polysilicon CMOS process. The chip contains a 10-bit A/D and an 8-bit D/A converters, a novel 128-step 0.375 dB/step programmable gain stage, 20-step 1dB/step programmable attenuator, switched-capacitor and active RC low-pass and high-pass filters for the receive and transmit directions, and all the associated TTL level compatible control logic. A CMOS band-gap voltage reference is shared between the receiver and transmitter. The chip, housed in 40-pin plastic package, is 223×219 mil2 and dissipates 120 mW using ±5V supplies.

Highpass and bandpass 2nd-order switched-capacitor filters

Highpass and bandpass switched-capacitor filters derived from Sallen and Key, and Bach's RC active highpass filters have been described. The bandpass filters have been shown to be realisable by simple modification of the highpass filters, using Laker's method of obtaining 1st-order lowpass filters from 1st-order highpass filters under certain input conditions. A single amplifier version of a recently described bandpass filter has also been discussed. All the realisations have been compared regarding the capacitor spread required to realise desired pole frequency and pole Q for given sampling frequency and optimised for minimal capacitor spread.

Electronically-Controlled Audio Filters

The use of filters whose cutoff characteristics are controllable by electronic means is often desirable in problems dealing with audio signals. Based on the recent work on fixed RC active filters by J. G. Linvill, variable active low-pass and high-pass filters have been developed using transistor negative-impedance converters. The design theory of such filters is summarized, and measured characteristics and other experimental results are presented. An application, in which the cutoff characteristics are controlled by the incoming audio signal for use in formant tracking, is described, and experimental results are given.