Wyniki wyszukiwania - BazTech

1

Implementation of low-output-impedance sinusoidal oscillator and Its modification for use in filters

Pawasarn Sanee, Charoenmee Angkana, Janda Thitiporn, Fungdetch Suttipong, Patimaprakorn Khunpan, Jantakun Adirek

Przegląd Elektrotechniczny

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2021

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R. 97, nr 8

96--103

EN

In this paper, we propose a voltage-mode sinusoidal oscillator and its modification for use in filters. The circuit comprises two commercially available ICs: LT1228, a single resistor, and only two grounded capacitors. The sinusoidal signals of the proposed circuit are generated with a 90° shift at low-output-impedance ports. The condition and frequency of the oscillation can be freely controlled by setting the transconductance gains. Furthermore, the frequency and amplitude of the signals can be directly controlled by adding external resistors to adjust the voltage amplifier. In addition, our proposed sinusoidal oscillator can be slightly modified for operation with low-pass, band-pass, and high-pass filters. The quality factor can be easily and independently set by adjusting the resistor values. The implementation is used to improve the theoretical analysis. All results are in accordance with the theoretical analysis.

PL

W pracy proponujemy napięciowy generator sinusoidalny i jego modyfikację do zastosowania w filtrach. Obwód składa się z dwóch dostępnych na rynku układów scalonych: LT1228, pojedynczego rezystora i tylko dwóch uziemionych kondensatorów. Sygnały sinusoidalne proponowanego układu są generowane z przesunięciem o 90° na portach o niskiej impedancji wyjściowej. Stan i częstotliwość oscylacji można dowolnie kontrolować, ustawiając wzmocnienia transkonduktancji. Ponadto częstotliwość i amplitudę sygnałów można bezpośrednio kontrolować poprzez dodanie zewnętrznych rezystorów do regulacji wzmacniacza napięcia. Proponowany przez nas generator sinusoidalny można nieznacznie zmodyfikować do pracy z filtrami dolnoprzepustowymi, pasmowoprzepustowymi i górnoprzepustowymi. Współczynnik jakości można łatwo i niezależnie ustawić, dostosowując wartości rezystorów. Implementacja służy do usprawnienia analizy teoretycznej. Wszystkie wyniki są zgodne z analizą teoretyczną.

2

Noise reduction for desert seismic data using spectral kurtosis adaptive bandpass filter

Ma Haitao, Qian Zebin, Li Yue, Lin Hongbo, Shao Dan, Yang Baojun

Acta Geophysica

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2019

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Vol. 67, no. 1

123--131

EN

In view of the heterogeneity and week similarity of random noise in the desert seismic exploration, and lots of random noise focused on low frequency, the traditional bandpass filter and wavelet transform are used to separate the signal and noise. Although there are some denoising effects, the noise cannot be suppressed well, and effective signal is damaged to some extent. Because of the above shortcomings, we propose a bandpass filter denoising method based on spectral kurtosis in this paper. This method is based on the signal and the random noise’s energy distribution characteristics in the frequency domain. First, through short-time Fourier transform (STFT), the spectral kurtosis of noisy signals is obtained. Second, we design a new threshold by the obtained spectral kurtosis, the value of spectral kurtosis greater than the threshold is preserved, and the spectral kurtosis less than the threshold is set to 0. So, the method realises the adaptive choice of the filter passband, getting an adaptive bandpass filter. At the same time, the noise can be suppressed to a greater extent while the effective signal is retained very well. The noise removal results of synthetic data and actual data show that the proposed method has very good denoising performance and amplitude preserving capability.

3

Design and Optimization of Rectangular Waveguide Filter based on Direct Coupled Resonators

Damou M., Nouri K., Feham M., Chetioui M.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 4

375--380

EN

The waveguide filter structure is treated by two softwares (HFSS (High Frequency Structure Simulator) and CST (Computer Simulation Technology)). Numerical example is given in this article to demonstrate, step by step, the application of the approach to the design of resonator, direct coupled waveguide and microstrip filters based on electromagnetic (EM) simulations. For this design procedure, the filter structure is simulated by successively adding one resonator at a time. To continue the work illustrates how to design a fourth order coupled resonator based rectangular waveguide circuit in the traditional way. With a large number of variables, such tuning work consumes a lot of time and the convergence of the final result is not guaranteed. A fourth order X-band bandpass filter with a center frequency of 11 GHz and a fractional bandwidth FBW = 0,0273 is designed using this procedure and presented here as an example. The simulated results by CST are presented and compared withthe results simulated by a high-frequency structure simulator. Good agreement between the simulated HFSSand simulated results by CST is observed.

4

Analysis of Substrate Integrated Waveguide (SIW) Resonator and Design of Miniaturized SIW Bandpass Filter

Rhbanou A., Bri S., Sabbane M.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 3

255--260

EN

In this paper, the substrate integrated waveguide (SIW) resonator is designed to study the influence of dielectric materials on its operating parameters (insertion loss, fractional bandwidth and unloaded Q-factor). The results obtained show that the use of high permittivity substrate in the SIW resonator by increasing its thickness allows reducing the size of resonator by causing the increase in its unloaded Q-factor. A SIW bandpass filter is designed using low temperature co-fired ceramic (LTCC) technology and high permittivity substrate. The filter has a fractional bandwidth of 27 % centered at 14.32 GHz with insertion loss of 0.7 dB.

5

A New Grounded Current Controlled Inductor Based on Simplified Current Conveyors

M'harzi Z., Alami M., Temcamani F.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 2

227--232

EN

In this paper, a new active grounded inductor controlled in current is described. This structure is realized using negative second generation current controlled conveyors and a single grounded capacitor, with no external resistance. The proposed circuit offers many advantages, such as: operation at high frequencies, simple circuit, tuning by the bias current, low power dissipation, etc. Comparison between this topology and those presented in literature is done to highlight the benefits of our structure. As an application, a bandpass filter based on the proposed active inductance is constructed to confirm the usability of the circuit and illustrate these performances. The filter center frequency and quality factor can be tuned independently. Simulation results, given under PSPICE software, present good agreement with the theoretical ones.

6

A 10.7-MHz Fully Balanced, Q-of-267, 103-dB-Dynamic-Range Current-Tunable Gm-C Bandpass Filter

Sa-Ngiamvibool W.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 10

204-209

EN

A 10.7-MHz fully balanced, high-Q, wide-dynamic-range current-tunable Gm-C bandpass filter is presented. The technique is relatively simple based on three fully balanced components, i.e. an adder, a low-Q-based bandpass filter and a differential amplifier. The high-Q factor is possible through a tunable bias current. As a simple example at 10.7 MHz, the paper demonstrates the high-Q factor of 267, the low total output noise of 2.089 Vrms, the 3rd-order intermodulation-free dynamic range (IMFDR3) of 82.59 dB and the wide dynamic range of 103 dB at 1% IM3. The center frequency is current tunable over 3 orders of magnitude. Comparisons to other 10.7-MHz Gm-C approaches are also included.

PL

Zaprezentowano strony prądowo filtr zrównoważony 10.7 MHz pasmowy Gm-C. Technologia bazuje na trzech elementach – sumatorze, filtrze pasmowym i wzmacniaczu różnicowym. Osiągnięto dużą dobroć dzięki strojeniu prądowemu. Przedstawiono przykład filtru i porównano z innymi filtrami.

7

64 channel neural recording amplifier with tunable bandwidth in 180 nm CMOS technology

Gryboś P., Kmon P., Żołądź M., Szczygieł R., Kachel M., Lewandowski M., Błasiak T.

Metrology and Measurement Systems

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2011

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Vol. 18, nr 4

631-643

EN

This paper presents the design and measurements of low-noise multichannel front-end electronics for recording extra-cellular neuronal signals using microelectrode arrays. The integrated circuit contains 64 readout channels and is fabricated in CMOS 180 nm technology. A single readout channel is built of an AC coupling circuit at the input, a low-noise preamplifier, a band-pass filter and a second amplifier. In order to reduce the number of output lines, the 64 analog signals from readout channels are multiplexed to a single output by an analog multiplexer. The chip is optimized for low noise and good matching performance and has the possibility of passband tuning. The low cut-off frequency can be tuned in the 1 Hz - 60 Hz range while the high cut-off frequency can be tuned in the 3.5 kHz - 15 kHz range. For the nominal gain setting at 44 dB and power dissipation per single channel of 220 žW, the equivalent input noise is in the range from 6 žV - 11 žV rms depending on the band-pass filter settings. The chip has good uniformity concerning the spread of its electrical parameters from channel to channel. The spread of the gain calculated as standard deviation to mean value is about 4.4% and the spread of the low cut-off frequency set at 1.6 Hz is only 0.07 Hz. The chip occupies 5×2.3 mm⊃2 of silicon area. To our knowledge, our solution is the first reported multichannel recording system which allows to set in each recording channel the low cut-off frequency within a single Hz with a small spread of this parameter from channel to channel. The first recordings of action potentials from the thalamus of the rat under urethane anesthesia are presented.

8

Integrated circuit with tunable bandwidth for neural signal recording

Kmon P.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 11a

90-93

EN

The architecture and preliminary measurements are presented of an ASIC for neural signal recording. The chip consists of 64 analogue channels followed by the analogue multiplexer and it is fabricated in the 180 nm CMOS technology. It consumes 220 ěW per channel from š0.9 V power supply. User is capable to modify frequency bandwidth in the 1 Hz – 60 Hz range for low cut-off frequency and 3.5 kHz – 15 kHz for high cutoff frequency. All measured parameters confirm the designed integrated circuit may be successfully used in neurobiology tests.

PL

Artykuł przedstawia architekturę oraz wstępne pomiary 64-o kanałowego dedykowanego układu scalonego przeznaczonego do pomiaru sygnałow żywych sieci neuronowych. Układ został wykonany w technologii 180nm. Pojedynczy kanał pobiera 220�ĘW mocy przy zasilaniu �[plus/minus]0.9V. Użytkownik ma możliwość regulacji dolnej i górnej częstotliwości granicznej w zakresie odpowiednio 1 Hz-60 Hz oraz 3.5 kHz-15 kHz.

9

The serially coupled multiple ring resonator filters and Vernier effect

Chaichuay C., Yupapin P. P., Saeung P.

Optica Applicata

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2009

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Vol. 39, nr 1

175--194

EN

The general characteristics of serially coupled multiple ring resonator (SMRR) filters are analyzed. In this case, the ring resonators of the SMRR have identical perimeters and the coupling coefficients distribution provides passband characteristics with steeper roll-off, flatter top and greater stopband rejection than a single ring resonator. In addition, we have also designed and simulated a nonsymmetric Vernier type of SMRR filters for improving a wide free spectral range (FSR) with different ring radii. To expand the FSR of the SMRR, Vernier filters are determined by the least common multiple of the FSR of individual ring resonators. The improvement in suppression of interstitial resonances is also investigated. A novel derivation of the optical transfer functions in Z-domain of SMRR filters is expressed employing a graphical approach to ring resonators with unequal perimeters that can be represented in signal flow graph diagrams.

10

Wpływ niedoskonałości elementów na działanie filtru pasmowoprzepustowego z zerem transmitancji na drugiej harmonicznej sygnału

Rudziński A.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 10

100-104

PL

W niniejszym artykule przedstawiono analizę wpływu skończonej dobroci elementów oraz rozrzutów ich wartości na działanie filtru pasmowoprzepustowego z zerem transmitancji. Wyprowadzone zostały przybliżone wyrażenia pozwalające określić wymaganą, dobroć i ograniczenia na rozrzuty wartości elementów składowych filtru.

EN

The aim of this paper is to present an analyzis of influence of finite quality factor and random dispersion of components' values on operation of a bandpass filter with transmission zero. Approximate expressions allowing to determine necessary quality factor and limitations of the dispersion of values have been obtained.

11

Ograniczenia przestrajania filtru pasmowoprzepustowego z zerem transmitancji na drugiej harmonicznej sygnału

Rudziński A.

Elektronika : konstrukcje, technologie, zastosowania

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2008

|

Vol. 49, nr 2

45-47

PL

W niniejszej pracy przedstawiona została analiza ograniczeń przestrajania filtru pasmowoprzepustowego z zerem transmitancji, uwarunkowanych przez zadane parametry filtru. Analize przeprowadzono przy założeniu idealności elementów składowych filtru i pominięciu praktycznych aspektów jego realizacji. Wyniki analizy pozwalają zatem wyznaczyć teoretyczne granice osiągalnego zakresu przestrajania, przy którym filtr zachowuje założone parametry, co umożliwia wstępną ocenę przydatności omawianej architektury filtru dla konkretnego zastosowania.

EN

This paper presents an analyzis of limitations of tuning of a bandpass filter with a transmission zero, fixed by the requirements put on the filter's parameters. The analyzis has been carried out for ideal filter components and without consideration of practical aspects of its realization. Obtained results allow therefore to determine theoretical limits of the possible tuning range, what allows for a preliminary estimation of the discussed filter's suitability for a specific application.