Notch Filtering Functions Research Articles

High-Efficiency High-Order CL-LLC DC/DC Converter With Wide Input Voltage Range

A novel multiresonant dc-dc converter is presented in this article, which owns a wide input voltage range and better voltage gain characteristics. Due to the addition of an antiresonant tank with a notch filter function, the converter introduces third harmonics in the power transmission, which can reduce the circulating energy in the resonant tank and reduce the loss of rectifier diode, thus improving the efficiency. The CL-LLC converter can realize soft switching in the full-load range. This article introduces the operating principle of the converter and the method of the parameters design. Finally, a 350-500 V input and 24 V/400-W prototype is designed to verify the correctness of the theory.

A Novel Multiresonant DC–DC Converter With Wide Output-Voltage Range

A novel multiresonant dc–dc converter with notch filter function is proposed in this article. The converter can regulate the output voltage over a wide range and has significant advantages in terms of gain. Due to its gain characteristics, the multiresonant converter has better inherent soft startup capability and over-current protection function. In addition, the switches of the converter can realize zero-voltage switching over the entire output-voltage range, and the output rectifier diode can realize zero-current switching. Compared with the traditional LLC converter, the multiresonant converter can use third harmonic to transmit the active power, and the loss caused by the reactive power cycle of the converter is reduced, which improve the efficiency. The converter parameters are optimized from the perspective of gain and efficiency in this article. Finally, a 2.5-kW experimental prototype is designed and the peak efficiency is 97.27%. The correctness of the theoretical analysis and the rationality of the parameter design are proved by the experimental results.

A UHF CMOS Variable Gain LNA with Wideband Input Impedance Matching and GSM Interoperability

A UHF CMOS variable gain low-noise amplifier (LNA) is designed for mobile digital TV tuners. The proposed LNA adopts a feedback topology to cover a wide frequency range from 474 to 868 MHz, and it supports the notch filter function for the interoperability with the GSM terminal. In order to handle harmonic distortion by strong interferers, the gain of the proposed LNA is step-controlled while keeping almost the same input impedance. The proposed LNA is implemented in a 0.11 mm CMOS process and consumes 6 mA at a 1.5 V supply voltage. In the measurement, it shows the power gain of greater than 16 dB, NF of less than 1.7 dB, and IIP3 of greater than -1.7 dBm for the UHF band.

UV-soft Imprinted Tunable Polymer Waveguide Ring Resonator for Microwave Photonic Filtering

A tunable polymer waveguide ring resonator is proposed and demonstrated for microwave photonic filtering. The ring resonator consists of a Mach–Zehnder interferometer (MZI) as the tunable coupler and two micro-heaters as the thermo-optic phase shifters. It was fabricated with inorganic–organic hybrid optical material polysiloxane-liquid series by a novel and simple UV-soft selective imprint technique. The coupling conditions, over-, critical- and under-coupling, were obtained with the micro-heater on the arm of MZI and the maximum notch depth of about 18 dB was achieved. The resonant wavelength was also tuned with the micro-heater on the ring waveguide. The dispersion induced power fading of radio over fiber link was overcome by the tunable ring resonator with its notch filtering function.

The effects of notch filtering on electrically evoked myoelectric signals and associated motor unit index estimates

BackgroundNotch filtering is the most commonly used technique for suppression of power line and harmonic interference that often contaminate surface electromyogram (EMG) signals. Notch filters are routinely included in EMG recording instrumentation, and are used very often during clinical recording sessions. The objective of this study was to quantitatively assess the effects of notch filtering on electrically evoked myoelectric signals and on the related motor unit index measurements.MethodsThe study was primarily based on an experimental comparison of M wave recordings and index estimates of motor unit number and size, with the notch filter function of the EMG machine (Sierra Wave EMG system, Cadwell Lab Inc, Kennewick, WA, USA) turned on and off, respectively. The comparison was implemented in the first dorsal interosseous (FDI) muscle from the dominant hand of 15 neurologically intact subjects and bilaterally in 15 hemiparetic stroke subjects.ResultsOn average, for intact subjects, the maximum M wave amplitude and the motor unit number index (MUNIX) estimate were reduced by approximately 22% and 18%, respectively, with application of the built-in notch filter function in the EMG machine. This trend held true when examining the paretic and contralateral muscles of the stroke subjects. With the notch filter on vs. off, across stroke subjects, we observed a significant decrease in both maximum M wave amplitude and MUNIX values in the paretic muscles, as compared with the contralateral muscles. However, similar reduction ratios were obtained for both maximum M wave amplitude and MUNIX estimate. Across muscles of both intact and stroke subjects, it was observed that notch filtering does not have significant effects on motor unit size index (MUSIX) estimate. No significant difference was found in MUSIX values between the paretic and contralateral muscles of the stroke subjects.ConclusionsThe notch filter function built in the EMG machine may significantly reduce the M wave amplitude and the MUNIX measurement. However, the notch filtering does not jeopardize the evaluation of the reduction ratio in maximum M wave amplitude and MUNIX estimate of the paretic muscles of stroke subjects when compared with the contralateral muscles.

Cascadable allpass and notch filters employing single operational transresistance amplifier

A new voltage-mode filter configuration is proposed. The presented topology uses single operational transresistance amplifier (OTRA) and can realize first-order allpass, second-order allpass and notch filtering functions. The proposed circuits are insensitive to parasitic capacitances and resistances due to internally grounded input terminals of OTRA. Low output impedance of the configuration enables the circuits to be cascaded without additional buffers. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA. Experimental work is also carried out. The feasibility of the proposed first-order allpass filter is illustrated on the design of a quadrature oscillator.

Power Line Communication Experiment using Wavelet OFDM in U.S..

Recently, the demand of high speed network in home is increasing, and PLC is expected as one of the solutions. We can see related researches on the high speed PLC system using a frequency band 2 MHz to 30 MHz. In this paper, we propose a wavelet based OFDM as a suitable method for realizing the high speed PLC system. The proposed wavelet OFDM method is composed of the M-band transmultiplexer which consists of the perfect reconstruction cosine-modulated filter bank. And the attenuation of the first side-lobe is above 35dB, which is a characteristic of the proposed method. As a result, we show that the proposed method has the inter-carrier interference characteristic which is superior to FFT-OFDM, and it also provides the flexible notch filter function which can reduce the influence on other communication systems existing in the communication band which the PLC uses. Finally, we describe that the simulation results about the BER characteristic of the proposed method in AWGN were almost the same as the theory, and that transmission rates which were measured by using prototype modems in a field test house in U.S. were above 35Mbps.

High impedance voltage- and current-mode multifunction filters

This paper presents a voltage- and current-mode multifunction filters based on and employing two four-terminal floating nullors (FTFNs) and a single operation transconductance amplifier (OTA). The high-input impedance voltage-mode configuration can simultaneously realize lowpass (LP), bandpass (BP) and notch filtering functions from the same configuration. The circuit employs two grounded capacitors which suits contemporary IC design techniques. The resonance frequency ω 0 and bandwidth ω 0 / Q can be independently tuned while as resonance frequency ω 0 and quality factor Q are orthogonally controllable. The current-mode configuration can simultaneously realize LP and highpass (HP) from which notch filtering signal can also be obtained. The input impedance of the circuit is very low while the output currents are available at very high impedances. The resonance frequency ω 0 and bandwidth ω 0 / Q can be orthogonally tuned. The high impedance of both the topologies in the two modes facilitates easy cascading for higher-order filter construction. Passive sensitivity figures are low. PSPICE simulation results are also included.

Design of biquad filters with a single current follower

Five new configurations of single current–follower–biquad (SCFB) filters are presented. They can synthesise second-order highpass, lowpass, bandpass, allpass, and notch filtering functions using a single current follower connected to four or more passive one-port RC elements. We have calculated the active and passive sensitivities to evaluate the circuit performance. The natural frequencies and the quality factors of most resulting SCFB filters will be insensitive to the current tracking error of the current follower. Experimental results which agree with theoretical analysis are obtained.

New CCII-based current-mode biquadratic filters

New configurations of current-mode biquadratic filters using second generation current conveyors (CCIIs) are presented. They can synthesize second-order high-pass, lowpass, bandpass, allpass, and notch filtering functions using CCIIs connected to four or more passive one-port RC elements. Active and passive sensitivities are calculated to evaluate the circuit performance. Experimental results which agree with the theoretical analysis are obtained.