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1
BRUSCHI, P., A. NANNINI, D. NAVARRINI, and M. PIOTTO. "FLICKER NOISE IN HETEROCYCLIC CONDUCTING POLYMER THIN FILM RESISTORS." Fluctuation and Noise Letters 02, no. 01 (March 2002): R1—R11. http://dx.doi.org/10.1142/s0219477502000555.
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The power spectral density of low frequency resistance fluctuation in heterocyclic conducting polymer thin film resistors was measured at various temperatures and bias current values. An accurate calculation of the background noise was performed in order to correct the measured power spectral densities. A parameter obtained normalizing the voltage power density to the sample volume and d.c. bias is used to compare the tested conducting polymers with various materials used for resistors fabrication.
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Sikula, J., J. Hlavka, J. Pavelka, V. Sedlakova, L. Grmela, M. Tacano, and S. Hashiguchi. "Low Frequency Noise of Tantalum Capacitors." Active and Passive Electronic Components 25, no. 2 (2002): 161–67. http://dx.doi.org/10.1080/08827510212341.
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A low frequency noise and charge carriers transport mechanism analysis was performed on tantalum capacitors in order to characterise their quality and reliability. The model ofTa−Ta2O5−MnO2MIS structure was used to give physical interpretation of VA characteristic both in normal and reverse modes. The self-healing process based on the high temperatureMnO2−Mn2O3transformation was studied and its kinetic determined on the basis of noise spectral density changes. The correlation between leakage current and noise spectral density was evaluated and noise reliability indicator was suggested. In normal mode the noise spectral density at rated voltage increases with second power of current and it varies within two decades for given leakage current value. In reverse mode there is only weak correlation and for given applied voltage, the leakage current for all ensemble varies only by one order, whereas the noise spectral density of the same samples spread in five orders.
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DANNEVILLE, F., B. TAMEN, A. CAPPY, J.-B. JURAVER, O. LLOPIS, and J. GRAFFEUIL. "LOW FREQUENCY NOISE CONVERSION IN FETS UNDER NONLINEAR OPERATION." Fluctuation and Noise Letters 01, no. 03 (September 2001): L189—L195. http://dx.doi.org/10.1142/s021947750100041x.
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The conversion mechanisms of microscopic low frequency noise sources (e.g. generation-recombination noise sources) located in the channel of a FET (Field Effect Transistor), in the presence of a large RF signal, are investigated. It is shown that the base-band (low frequency) input gate noise voltage spectral density is strongly dependent on the magnitude of the input RF power applied to the FET. Moreover, the microscopic generation-recombination noise sources distributed along the channel are also responsible of up-converted input gate noise voltage spectral density around the RF frequency.
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Patel, Dhara P., and Shruti Oza-Rahurkar. "CMOS Active Inductor/Resonator Based Voltage Controlled Oscillator." Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 12, no. 6 (November 22, 2019): 500–506. http://dx.doi.org/10.2174/2352096511666181105111852.
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Background: A tunable CMOS active inductor/resonator based Voltage Controlled Oscillator (VCO) has been presented. In the design of LC-VCO, LC resonator (tank) circuit has been substituted with gyrator based CMOS active inductor/resonator. The purity of VCO output signal is defined by the phase noise parameter. Methods: For good spectral purity of VCO output signal, the phase noise should be minimum. Moreover, the quality factor of LC resonator is inversely proportional to the phase noise of VCO output signal. In the presented work, a high-quality active inductor/resonator circuit has been used to design VCO which minimizes the phase noise and chip area as well. Further, other VCO characterization factors are measured. Results: The designed circuit has been implemented in 0.18µm CMOS technology. Conclusion: The design of the proposed AI based voltage controlled oscillator shows better phase noise, less chip area and high output power. The high output power is achieved at the cost of limited tuning range of 1.14 GHz ~ 2.1 GHz. The presented active inductor based voltage controlled oscillator can be used for RF applications from 1.14GHz ~ 2.1GHz.
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Zhong, Kai, Yuan Liu, Shu-Ting Cai, and Xiao-Ming Xiong. "Temperature dependence of conduction and low frequency noise characteristics in hydrogenated amorphous silicon thin film transistors." Modern Physics Letters B 33, no. 02 (January 20, 2019): 1950009. http://dx.doi.org/10.1142/s021798491950009x.
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The transfer and low frequency noise characteristics of hydrogenated amorphous silicon thin film transistors (a-Si:H TFTs) were measured in the temperature range of 230–430 K. The variation of threshold voltage, field effect mobility and sub-threshold swing with increasing temperatures were then extracted and analyzed. Moreover, the shifts of low frequency noise in the a-Si:H TFT under various temperatures are reported for the first time. The variation of flatband voltage noise power spectral density with temperature is also calculated and discussed.
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Ciura, Łukasz, Andrzej Kolek, Waldemar Gawron, Andrzej Kowalewski, and Dariusz Stanaszek. "Measurements of Low Frequency Noise of Infrared Photo-Detectors with Transimpedance Detection System." Metrology and Measurement Systems 21, no. 3 (August 21, 2014): 461–72. http://dx.doi.org/10.2478/mms-2014-0039.
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Abstract The paper presents the method and results of low-frequency noise measurements of modern mid-wavelength infrared photodetectors. A type-II InAs/GaSb superlattice based detector with nBn barrier architecture is compared with a high operating temperature (HOT) heterojunction HgCdTe detector. All experiments were made in the range 1 Hz - 10 kHz at various temperatures by using a transimpedance detection system, which is examined in detail. The power spectral density of the nBn’s dark current noise includes Lorentzians with different time constants while the HgCdTe photodiode has more uniform 1/f - shaped spectra. For small bias, the low-frequency noise power spectra of both devices were found to scale linearly with bias voltage squared and were connected with the fluctuations of the leakage resistance. Leakage resistance noise defines the lower noise limit of a photodetector. Other dark current components give raise to the increase of low-frequency noise above this limit. For the same voltage biasing devices, the absolute noise power densities at 1 Hz in nBn are 1 to 2 orders of magnitude lower than in a MCT HgCdTe detector. In spite of this, low-frequency performance of the HgCdTe detector at ~ 230K is still better than that of InAs/GaSb superlattice nBn detector.
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Chan, Hua Khee, Rupert C. Stevens, Jonathan P. Goss, Nicholas G. Wright, and Alton B. Horsfall. "Reliability Evaluation of 4H-SiC JFETs Using I-V Characteristics and Low Frequency Noise." Materials Science Forum 740-742 (January 2013): 934–37. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.934.
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Two sets of 4H-SiC signal-lateral JFETs were thermally aged at 400°C and 500°C in furnaces open to air for 1000 hours. I"-" V and low frequency noise measurements were performed on these devices and the results were compared against the as-fabricated sample. The data from I"-" V characterisation demonstrates that the linear and saturated drain-source current decreases monotonically with stress temperature. In addition, the linear characteristics of the JFETs have shifted approximately 1.5V along the drain-source voltage axis. Whilst the devices thermally aged at 400°C show no degradation in magnitude and behaviour in Noise Power Spectral Density (NPSD), the NPSD of 500°C stressed devices has increase approximately 30dB and it shows a full frequency spectrum of 1/ƒ dependency up to 100 kHz. A further investigation of the noise origin reveals that the Normalised Noise Power Spectral Density (NNPSD) of the aged sample is directly proportional to RDSwhich is similar to the as-fabricated sample. Thus we hypothesize that the existing noise sources have intensified possibly due to the evolution of defects.
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Savelyev, S. V., and L. A. Morozova. "HIGH POWER CHAOTIC OSCILLATOR." Electronic engineering Series 2 Semiconductor devices 259, no. 4 (2020): 31–36. http://dx.doi.org/10.36845/2073-8250-2020-259-4-31-36.
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The article presents a novel design of a microwave chaotic oscillator. The oscillator contains an inertial converter for the nonlinear amplifier output signal that modulates the supply voltage of the transistor. When the inertia of the converter becomes less than 0.06, the oscillator demonstrates chaotic behavior. We present an experimental model of a chaotic oscillator based on a high power transistor 2T982A-2. The inertial converter circuit contains a diode that perform half-wave conversion of a part of the output signal and a RC circuit with a time constant equal to 0.05 of the duration of an oscillation at the central frequency of the oscillator. The output signal of the inertial converter has been applied to the emitter power supply circuit of the transistor. Modulation of the supply voltage caused the output signal of the oscillator to become a sequence of non-repeating oscillation trains with a random duration and initial phase. The frequency band of the generated chaos with an uneven power spectrum of 4 dB was in a range from 3.1 to 3.3 GHz with an integrated power of 1.2 W. The averaged spectral density of noise oscillations was 6 10-3 W / MHz. Efficiency of the oscillator was 15%.
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Bulatov, Yuri, Andrey Kryukov, and Nguyen Van Huan. "Flicker control in mains with distributed generation plants." E3S Web of Conferences 209 (2020): 07001. http://dx.doi.org/10.1051/e3sconf/202020907001.
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The use of distributed generation (DG) plants in power supply systems is a rapid development line. However, the impact of DG on power quality is multivalued. On the one hand, the presence of DG allows to reduce voltage losses. On the other hand, a phenomenon called flicker and associated with rapid voltage fluctuations is possible. This effect is usually manifested at an abrupt voltage drop in the DG generator connection unit. The processes taking place in the network when flicker occurs in networks with DG have not been sufficiently studied. The article presents results of the flicker modeling in a network equipped with DG plants, implemented on the basis of synchronous generators. The results obtained indicated that with sharp disturbances caused by switching on and off an additional load, flicker is observed in networks with unregulated generators, accompanied by voltage and frequency fluctuations. Based on the wavelet transformation and spectral analysis methods, it was found that the power spectral density of the generated flicker-noise is inversely proportional to the frequency. The use of look-ahead control algorithms to control the excitation and rotors rotational speed of the DG plants generators, as well as concordant adjustment of their controllers, increases stability and removes flicker completely.
10
Liu, Yuan, Yun-Fei En, and Wen-Xiao Fang. "Analysis of low frequency noise characteristics in p-type polycrystalline silicon thin film transistors." Modern Physics Letters B 31, no. 19-21 (July 27, 2017): 1740020. http://dx.doi.org/10.1142/s0217984917400206.
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Low frequency noises in the p-type polycrystalline silicon thin film transistors are investigated. It shows a pure 1/f[Formula: see text] (with [Formula: see text] near one) noise behavior which can be explained by emission and trapping processes of carriers between trapping states. Subsequently, the gate voltage-dependent drain current noise power spectral densities closely follow the mobility fluctuation model, and the average Hooge’s parameter is then extracted. By considering traditional tunneling processes, the flat-band voltage spectral density is extracted and the concentration of traps in the grain boundary is calculated to be [Formula: see text]. By converting the frequency to tunneling depth of carriers in the gate oxide, the spatial distribution of gate oxide trapped charges are obtained. Finally, the distribution of localized states in the energy band is extracted. The experimental results show an exponential deep states and tail states distribution in the band gap while [Formula: see text] is about [Formula: see text], [Formula: see text] is [Formula: see text][Formula: see text]617 K, [Formula: see text] is [Formula: see text] and [Formula: see text] is [Formula: see text][Formula: see text]265 K.
11
M. A. Eid, Mahmoud, Ashraf S. Seliem, Ahmed Nabih Zaki Rashed, Abd El-Naser A. Mohammed, Mohamed Yassin Ali, and Shaimaa S. Abaza. "Duobinary modulation/predistortion techniques effects on high bit rate radio over fiber systems." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (February 1, 2021): 978. http://dx.doi.org/10.11591/ijeecs.v21.i2.pp978-986.
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<span>The work has presented duobinary modulation and predistortion techniques for the radio over fiber system enhancement for achieving security level. Duobinary modulation technique has more compact modulated spectral linewidth with standard non return to zero modulation code. Different NRZ/RZ rectangle shape employed that are namely exponential rectangle shape (ERS), and Gaussian rectangle shape (GRS) for different transmission bit rates. Switching bias voltage, and switching RF voltage based LiNbO<sub>3</sub> modulator are changed to measure the performance parameters of the radio over fiber (RoF) system. Predistortion technique improves the linearity of transmitter amplifiers and it is considered as a power efficiency technique. The optimum values of the Q-factor, data error rate (BER), electrical power, signal gain, noise figure, and light signal/noise ratio are achieved with 8 Volt for both switching biases/switching RF signal at 100 GHz. Signal quality/BER and electrical power after the receiver enhancement ratio by using this technique at different RF signal frequencies. </span>
12
Hainsworth, A. H., R. A. Levis, and R. S. Eisenberg. "Origins of open-channel noise in the large potassium channel of sarcoplasmic reticulum." Journal of General Physiology 104, no. 5 (November 1, 1994): 857–83. http://dx.doi.org/10.1085/jgp.104.5.857.
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Open-channel noise was studied in the large potassium channel of the sarcoplasmic reticulum (SR). Inside-out patches were excised directly from the SR of split skeletal muscle fibers of lobster, with lobster relaxing ringer (LRR) in bath and pipette. The power spectrum of open-channel noise is very low and approximately flat in the 100 Hz-10 kHz frequency range. At 20 degrees C, with an applied voltage of 50 mV, the mean single-channel current (i) is 9 pA (mean single-channel conductance = 180 pS) and the mean power spectral density 1.1 x 10(-29) A2/Hz. The latter increases nonlinearly with (i), showing a progressively steeper dependence as (i) increases. At 20 mV, the mean power spectral density is almost independent of (i) and approximately 1.4 times that of the Johnson noise calculated for the equivalent ideal resistor with zero net current; at 70 mV it increases approximately in proportion to (i)2. The mean power spectral density has a weak temperature dependence, very similar to that of (i), and both are well described by a Q10 of 1.3 throughout the range 3-40 degrees C. Discrete ion transport events are thought to account for a significant fraction of the measured open-channel noise, probably approximately 30-50% at 50 mV. Brief interruptions of the single-channel current, due either to blockage of the open channel by an extrinsic aqueous species, or to intrinsic conformational changes in the channel molecule itself, were a possible additional source of open-channel noise. Experiments in modified bathing solutions indicate, however, that open-channel noise is not affected by any of the identified aqueous species present in LRR. In particular, magnesium ions, the species thought most likely to cause brief blockages, and calcium and hydrogen ions, have no detectable effect. This channel's openings exhibit many brief closings and substrates, due to intrinsic gating of the channel. Unresolved brief full closings are calculated to make a negligible contribution (< 1%) to the measured power spectral density. The only significant source of noise due to band width-limited missed events is brief, frequent 80% substrates (mean duration 20 microseconds, mean frequency 1,000 s-1) which account for a small part of the measured power spectral density (approximately 14%, at 50 mV, 20 degrees C). We conclude that a large fraction of the measured open-channel noise results from intrinsic conductance fluctuations, with a corner frequency higher than the resolution of our recordings, in the range 10(4)-10(7) Hz.(ABSTRACT TRUNCATED AT 400 WORDS)
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Ardila Rey, Jorge Alfredo, Ricardo Albarracín Sánchez, and Guillermo Robles. "A new monitoring and characterization system of partial discharges based on the analysis of the spectral power." Ingeniería e Investigación 35, no. 1Sup (November 18, 2015): 13–20. http://dx.doi.org/10.15446/ing.investig.v35n1sup.53584.
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<p>Partial Discharges (PD) are one of the possible causes for unexpected faults in power systems equipment, so that its measure is an essential tool for high-voltage electrical equipment maintenance. In order to characterize the PD activity, some statistic magnitudes are necessary. For this reason, the acquisition and processing of PD is very important when making critical decisions regarding disconnection or repairing assets in power systems. On the other hand, the measurement environments often present multiple sources of electrical noise, thus the proper interpretation of PD patterns is a challenge in the identification of sources of different nature. In this paper, the development of a PD monitoring system capable of displaying in real time the classic PD parameters, the PD waveform, its frequency spectrum and calculating statistical parameters of the acquisition, are presented. On the whole, a new method of identifying sources of PD and electrical noise, developed by the authors, which is based on measuring the relative spectral power of PD pulses, is shown. This method has proven effective in characterizing PD and electrical noise; a series of experiments conducted in several test objects are presented in order to validate the performance of the proposed system</p><p><span><br /><br class="Apple-interchange-newline" /></span></p>
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Zucker, Robert M., and Owen T. Price. "Optimization and the Evaluation of Confocal System Performance to Quantify Fluorescence." Microscopy and Microanalysis 5, S2 (August 1999): 464–65. http://dx.doi.org/10.1017/s1431927600015646.
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The laser scanning confocal microscope (LSCM) has enormous potential in many fields of biology. Quality assurance is essential for the equipment to function correctly and realize its fullest potential. Currently the assessment of a confocal microscope’s performance is subjective primarily by evaluating the system with a specific test slide provided by the user. To achieve better performance, it is necessary to run a series of validation tests. These tests that were applied to measure field illumination, lens, clarity, dichroic functioning, objective spectral alignment, axial resolution, laser power and stability, photomultiplier tube (PMT) functioning, and system noise. Although th?se tests were derived on a Leica TCS-SP system and Leica TCD4D system, they should be applicable to other manufacturers’ systems.For optimal images, it is important to control the variables of laser power, PMT tube voltage, averaging, and bleaching. The relationship between PMT voltage, laser power, and averaging was determined using a Spherotech Rainbow 10 μm diameter test bead. It was demonstrated that the noise (coefficient of variation of bead intensity, CV) in an image greatly increases as the PMT increases. The system variables that affected the precision and accuracy of the confocal system will be discussed.
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Oulmi, K., K. E. Bouhidel, and G. M. Andreadis. "Noise spectra of K+ and NH4+ ions at over-limiting current in an electrochemical system with a cation exchange membrane." Journal of Water Reuse and Desalination 3, no. 3 (March 12, 2013): 291–96. http://dx.doi.org/10.2166/wrd.2013.001.
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The present work investigates the effect of the counter ion nature on the noise of the over-limiting current (Iov). Moreover, the electrochemical methods, current voltage curve (I–V) and the chronopotentiometry (V–t) measurements are applied. The over-limiting current is always accompanied by a neat electrical noise. It is a well accepted experimental phenomenon. The study of this noise may contribute to a better understanding of the Iov and the feasibility of electrodialysis operation at this current in terms of energy consumption. The electrical noise depends directly on the counter ion nature. The power spectral density of the membrane's potential fluctuation was obtained via Fourier analysis of the time series recorded during the transport of counter ions (K+ and NH4+). The spectra are evaluated above the limiting current indicating the differences between the K+ and the NH4+. It is found that the cation NH4+ presents a singular behaviour and the noise is minimal.
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Trabelsi, Mohamed, Nabil Sghaier, Jean Marie Bluet, Noureddine Yacoubi, Gérard Guillot, and Christian Brylinski. "Time Domain and Frequency Analysis of Random Telegraph Signal and the Contributions of G-R Centres to I-V Instabilities in 4H-SiC MESFETs." Materials Science Forum 527-529 (October 2006): 1251–54. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.1251.
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Our work is focused on the identification of defects responsible for current fluctuations at the origin of low frequency noise or random telegraphic signals in 4H-SiC MESFETs on semiinsulating (SI) substrates. We show that devices having instabilities have DC output characteristics with random discrete fluctuations of the drain current. The RTS noise parameters analysis (amplitude, high and low state time durations) as a function of temperature and bias voltage provides the signature of the involved traps (activation energy and cross section both for emission and capture). From the power spectral density of the drain current noise (PSD) we have measured the cut-off frequency of a single trap even at very low frequencies (from 0.1 Hz) and we propose that the noise responsible of RTS fluctuations is a generation-recombination noise. Finally, it is shown that the frequency analysis of the random telegraphic signal is a well-suited tool for the study of single defects in very small devices.
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Lee, Jaehoon, Changyeop Jeon, Taehyeong Jeon, Proloy Das, Yongho Lee, Byeonghwa Lim, and CheolGi Kim. "Bridge Resistance Compensation for Noise Reduction in a Self-Balanced PHMR Sensor." Sensors 21, no. 11 (May 21, 2021): 3585. http://dx.doi.org/10.3390/s21113585.
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Advanced microelectromechanical system (MEMS) magnetic field sensor applications demand ultra-high detectivity down to the low magnetic fields. To enhance the detection limit of the magnetic sensor, a resistance compensator integrated self-balanced bridge type sensor was devised for low-frequency noise reduction in the frequency range of 0.5 Hz to 200 Hz. The self-balanced bridge sensor was a NiFe (10 nm)/IrMn (10 nm) bilayer structure in the framework of planar Hall magnetoresistance (PHMR) technology. The proposed resistance compensator integrated with a self-bridge sensor architecture presented a compact and cheaper alternative to marketable MEMS MR sensors, adjusting the offset voltage compensation at the wafer level, and led to substantial improvement in the sensor noise level. Moreover, the sensor noise components of electronic and magnetic origin were identified by measuring the sensor noise spectral density as a function of temperature and operating power. The lowest achievable noise in this device architecture was estimated at ~3.34 nV/Hz at 100 Hz.
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Yoon, Daseul, Ji-Hoon Kim, and Sung Min Park. "Complementary Metal-Oxide-Semiconductor Symmetric Current-Conveyor Transimpedance Amplifier." Journal of Nanoscience and Nanotechnology 20, no. 8 (August 1, 2020): 4793–98. http://dx.doi.org/10.1166/jnn.2020.17808.
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This paper presents a novel symmetric current-conveyor transimpedance amplifier (SCC-TIA) implemented in a 0.13-μm CMOS technology for the applications of LiDAR systems, where a modifiedcascode configuration is newly proposed for input current buffer to deliver the photo-currents to the following voltage-mode inverter TIA without signal loss. Measured results of the proposed SCC-TIA demonstrate 69-dBΩ transimpedance gain, 410-MHz bandwidth, 13-pA/sqrt (Hz) average noise current spectral density, and 20-mW power dissipation from a single 1.2-V supply. Chip core occupies the area of 280×130 μm2.
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Kolios, Vasilis, Konstantinos Giannakidis, and Grigorios Kalivas. "60 GHz Front-End Components for Broadband Wireless Communication in 130 nm CMOS Technology." Image Processing & Communications 21, no. 1 (March 1, 2016): 67–77. http://dx.doi.org/10.1515/ipc-2016-0006.
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Abstract The over 5 GHz available spectral space allocated worldwide around the 60 GHz band, is very promising for very high data rate wireless short-range communications. In this article we present two key components for the 60 GHz front-end of a transceiver, in 130 nm RF CMOS technology: a single-balanced mixer with high Conversion Gain (CG), reduced Noise Figure (NF) and low power consumption, and an LC cross-coupled Voltage Controlled Oscillator (VCO) with very good linearity, with respect to Vctrl, and very low Phase Noise (PN). In both circuits, custom designed inductors and a balun structure for the mixer are employed, in order to enhance their performance. The VCO’s inductor achieves an inductance of 198 pH and a quality factor (Q) of 30, at 30 GHz. The balun shows less than 1o Phase Imbalance (PI) and less than 0.2 dB Amplitude Imbalance (AI), from 57 to 66 GHz. The mixer shows a CG greater than 15 dB and a NF lower than 12 dB. In addition, the VCO achieves a Phase Noise lower than -106 dBc/Hz at 1 MHz offset, and shows great linearity for the entire band. Both circuits are biased with a 1.2 V supply voltage and the total power consumption is about 10.6 mW for the mixer and 10.92 mW for the VCO.
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JHA, SHRAWAN K., CHANG-FEI ZHU, MANFRED H. PILKUHN, CHARLES SURYA, and HEINZ SCHWEIZER. "DEGRADATION OF LOW-FREQUENCY NOISE IN AlGaN/GaN HEMTS DUE TO HOT-ELECTRON STRESSING." Fluctuation and Noise Letters 07, no. 01 (March 2007): L91—L100. http://dx.doi.org/10.1142/s0219477507003726.
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We report on the degradation of low-frequency excess noise in recessed gate AlGaN/GaN HEMTs due to hot-electron stressing. The I-V characteristics and the low-frequency noise power spectral densities, SV(f), of the open circuit voltage fluctuations across the drain source terminal were characterized with the stress time. Based on these results, we observed that the overall low-frequency noise degradation process can be identified to occur in two distinct phases. In the first phase, devices initially show fluctuations in the noise properties around a relatively constant average value. Detailed characterizations of the gate-source bias, VGS, dependence of SV(f) at cryogenic temperatures indicate signature-patterns in the variations of SV(f) as a function of VGS. This is shown to arise from the modulation of the percolation paths of the carriers in the two-dimensional electron gas (2DEG). The onset of the second phase of degradation arises from the irreversible generation of interface states at the AlGaN/GaN hetero-interface.
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Li, Xiangyu, Liang Yin, Weiping Chen, Zhiqiang Gao, and Xiaowei Liu. "A high-resolution tunneling magneto-resistance sensor interface circuit." Modern Physics Letters B 31, no. 04 (February 10, 2017): 1750030. http://dx.doi.org/10.1142/s0217984917500300.
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In this paper, a chopper instrumentation amplifier and a high-precision and low-noise CMOS band gap reference in a standard 0.5 [Formula: see text] CMOS technology for a tunneling magneto-resistance (TMR) sensor is presented. The noise characteristic of TMR sensor is an important factor in determining the performance of the sensor. In order to obtain a larger signal to noise ratio (SNR), the analog front-end chip ASIC weak signal readout circuit of the sensor includes the chopper instrumentation amplifier; the high-precision and low-noise CMOS band gap reference. In order to achieve the low noise, the chopping technique is applied in the first stage amplifier. The low-frequency flicker noise is modulated to high-frequency by chopping switch, so that the modulator has a better noise suppression performance at the low frequency. The test results of interface circuit are shown as below: At a single 5 V supply, the power dissipation is 40 mW; the equivalent offset voltage is less than 10 uV; the equivalent input noise spectral density 30 nV/Hz[Formula: see text](@10 Hz), the equivalent input noise density of magnetic is 0.03 nTHz[Formula: see text](@10 Hz); the scale factor temperature coefficient is less than 10 ppm/[Formula: see text]C, the equivalent input offset temperature coefficient is less than 70 nV/[Formula: see text]C; the gain error is less than 0.05%, the common mode rejection ratio is greater than 120 dB, the power supply rejection ratio is greater than 115 dB; the nonlinear is 0.1% FS.
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ABEDIN, M. NURUL, TAMER F. REFAAT, OLEG V. SULIMA, and UPENDRA N. SINGH. "RECENT DEVELOPMENT OF SB-BASED PHOTOTRANSISTORS IN THE 0.9- TO 2.2-μM WAVELENGTH RANGE FOR APPLICATIONS TO LASER REMOTE SENSING." International Journal of High Speed Electronics and Systems 16, no. 02 (June 2006): 567–82. http://dx.doi.org/10.1142/s0129156406003850.
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We have investigated commercially available photodiodes and also recent developed Sb -based phototransistors in order to compare their performances for applications to laser remote sensing. A custom-designed phototransistor in the 0.9- to 2.2-μm wavelength range has been developed at AstroPower and characterized at NASA Langley's Detector Characterization Laboratory. The phototransistor's performance greatly exceeds the previously reported results at this wavelength range in the literature. The detector testing included spectral response, dark current and noise measurements. Spectral response measurements were carried out to determine the responsivity at 2-μm wavelength at different bias voltages with fixed temperature; and different temperatures with fixed bias voltage. Current versus voltage characteristics were also recorded at different temperatures. Results show high responsivity of 2650 AIW corresponding to an internal gain of three orders of magnitude, and high detectivity (D*) of 3.9×1011 cm.Hz 1/2/ W that is equivalent to a noise-equivalent-power of 4.6×10-14 W/Hz 1/2 (-4.0 V @ -20°C) with a light collecting area diameter of 200-μm. It appears that this recently developed 2-μm phototransistor's performances such as responsivity, detectivity, and gain are improved significantly as compared to the previously published APD and SAM APD using similar materials. These detectors are considered as phototransistors based-on their structures and performance characteristics and may have great potential for high sensitivity differential absorption lidar (DIAL) measurements of carbon dioxide and water vapor at 2.05-μm and 1.9-μm, respectively.
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Lee, Sung Hyun, Naoki Sunaguchi, Akie Nagao, Yoshiyuki Hirano, Hiroshi Sakurai, Yosuke Kano, Masami Torikoshi, Tatsuaki Kanai, and Mutsumi Tashiro. "Calculation of Stopping-Power Ratio from Multiple CT Numbers Using Photon-Counting CT System: Two- and Three-Parameter-Fitting Method." Sensors 21, no. 4 (February 9, 2021): 1215. http://dx.doi.org/10.3390/s21041215.
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The two-parameter-fitting method (PFM) is commonly used to calculate the stopping-power ratio (SPR). This study proposes a new formalism: a three-PFM, which can be used in multiple spectral computed tomography (CT). Using a photon-counting CT system, seven rod-shaped samples of aluminium, graphite, and poly(methyl methacrylate) (PMMA), and four types of biological phantom materials were placed in a water-filled sample holder. The X-ray tube voltage and current were set at 150 kV and 40 μμA respectively, and four CT images were obtained at four threshold settings. A semi-empirical correction method that corrects the difference between the CT values from the photon-counting CT images and theoretical values in each spectral region was also introduced. Both the two- and three-PFMs were used to calculate the effective atomic number and electron density from multiple CT numbers. The mean excitation energy was calculated via parameterisation with the effective atomic number, and the SPR was then calculated from the calculated electron density and mean excitation energy. Then, the SPRs from both methods were compared with the theoretical values. To estimate the noise level of the CT numbers obtained from the photon-counting CT, CT numbers, including noise, were simulated to evaluate the robustness of the aforementioned PFMs. For the aluminium and graphite, the maximum relative errors for the SPRs calculated using the two-PFM and three-PFM were 17.1% and 7.1%, respectively. For the PMMA and biological phantom materials, the maximum relative errors for the SPRs calculated using the two-PFM and three-PFM were 5.5% and 2.0%, respectively. It was concluded that the three-PFM, compared with the two-PFM, can yield SPRs that are closer to the theoretical values and is less affected by noise.
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Palenskis, Vilius, Linas Minkevičius, Jonas Matukas, Domas Jokubauskis, Sandra Pralgauskaitė, Dalius Seliuta, Bronislovas Čechavičius, Renata Butkutė, and Gintaras Valušis. "InGaAs Diodes for Terahertz Sensing—Effect of Molecular Beam Epitaxy Growth Conditions." Sensors 18, no. 11 (November 3, 2018): 3760. http://dx.doi.org/10.3390/s18113760.
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InGaAs-based bow-tie diodes for the terahertz (THz) range are found to be well suited for development of compact THz imaging systems. To further optimize design for sensitive and broadband THz detection, one of the major challenges remains: to understand the noise origin, influence of growth conditions and role of defects for device operation. We present a detailed study of photoreflectance, low-frequency noise characteristics and THz sensitivity of InGaAs bow-tie diodes. The diodes are fabricated from InGaAs wafers grown by molecular beam epitaxy (MBE) on semi-insulating InP substrate under different technological conditions. Photoreflectance spectra indicated the presence of strong built-in electric fields reaching up to 49 kV/cm. It was demonstrated that the spectral density of voltage fluctuations at room temperature was found to be proportional to 1/f, while at lower temperatures, 77–200 K, Lorentzian-type spectra dominate due to random telegraph signals caused by individual capture defects. Furthermore, varying bias voltage, we considered optimal conditions for device room temperature operation in the THz range with respect to signal-to-noise ratio. The THz detectors grown with beam equivalent pressure In/Ga ratio equal to 2.04 exhibit the minimal level of the low-frequency noise, while InGaAs layers grown with beam equivalent pressure In/Ga ratio equal to 2.06 are found to be well suited for fabrication of room temperature bow-tie THz detectors enabling sensitivity of 13 V/W and noise equivalent power (NEP) of 200 pW/√Hz at 0.6 THz due to strong built-in electric field effects.
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Manwani, Amit, and Christof Koch. "Detecting and Estimating Signals in Noisy Cable Structures, I: Neuronal Noise Sources." Neural Computation 11, no. 8 (November 1, 1999): 1797–829. http://dx.doi.org/10.1162/089976699300015972.
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In recent theoretical approaches addressing the problem of neural coding, tools from statistical estimation and information theory have been applied to quantify the ability of neurons to transmit information through their spike outputs. These techniques, though fairly general, ignore the specific nature of neuronal processing in terms of its known biophysical properties. However, a systematic study of processing at various stages in a biophysically faithful model of a single neuron can identify the role of each stage in information transfer. Toward this end, we carry out a theoretical analysis of the information loss of a synaptic signal propagating along a linear, one-dimensional, weakly active cable due to neuronal noise sources along the way, using both a signal reconstruction and a signal detection paradigm. Here we begin such an analysis by quantitatively characterizing three sources of membrane noise: (1) thermal noise due to the passive membrane resistance, (2) noise due to stochastic openings and closings of voltage-gated membrane channels (Na+ and K+), and (3) noise due to random, background synaptic activity. Using analytical expressions for the power spectral densities of these noise sources, we compare their magnitudes in the case of a patch of membrane from a cortical pyramidal cell and explore their dependence on different biophysical parameters.
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Omura, Yasuhisa. "Empirical and Theoretical Modeling of Low-Frequency Noise Behavior of Ultrathin Silicon-on-Insulator MOSFETs Aiming at Low-Voltage and Low-Energy Regime." Micromachines 10, no. 1 (December 22, 2018): 5. http://dx.doi.org/10.3390/mi10010005.
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This paper theoretically revisits the low-frequency noise behavior of the inversion-channel silicon-on-insulator metal-oxide-semiconductor field-effect transistor (SOI MOSFET) and the buried-channel SOI MOSFET because the quality of both Si/SiO2 interfaces (top and bottom) should modulate the low-frequency fluctuation characteristics of both devices. It also addresses the low-frequency noise behavior of sub-100-nm channel SOI MOSFETs. We deepen the discussion of the low-frequency noise behavior in the subthreshold bias range in order to elucidate the device’s potential for future low-voltage and low-power applications. As expected, analyses suggest that the weak inversion channel near the top surface of the SOI MOSFET is strongly influenced by interface traps near the top surface of the SOI layer because the traps are not well shielded by low-density surface inversion carriers in the subthreshold bias range. Unexpectedly, we find that the buried channel is primarily influenced by interface traps near the top surface of the SOI layer, not by traps near the bottom surface of the SOI layer. This is not due to the simplified capacitance coupling effect. These interesting characteristics of current fluctuation spectral intensity are explained well by the theoretical models proposed here.
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Cherny, Vladimir V., Ricardo Murphy, Valerij Sokolov, Richard A. Levis, and Thomas E. DeCoursey. "Properties of Single Voltage-gated Proton Channels in Human Eosinophils Estimated by Noise Analysis and by Direct Measurement." Journal of General Physiology 121, no. 6 (May 27, 2003): 615–28. http://dx.doi.org/10.1085/jgp.200308813.
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Voltage-gated proton channels were studied under voltage clamp in excised, inside-out patches of human eosinophils, at various pHi with pHo 7.5 or 6.5 pipette solutions. H+ current fluctuations were observed consistently when the membrane was depolarized to voltages that activated H+ current. At pHi ≤ 5.5 the variance increased nonmonotonically with depolarization to a maximum near the midpoint of the H+ conductance-voltage relationship, gH-V, and then decreased, supporting the idea that the noise is generated by H+ channel gating. Power spectral analysis indicated Lorentzian and 1/f components, both related to H+ currents. Unitary H+ current amplitude was estimated from stationary or quasi-stationary variance, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\sigma}}_{\mathrm{H}}^{\mathrm{2}}\) \end{document}. We analyze \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\sigma}}_{\mathrm{H}}^{\mathrm{2}}\) \end{document} data obtained at various voltages on a linearized plot that provides estimates of both unitary conductance and the number of channels in the patch, without requiring knowledge of open probability. The unitary conductance averaged 38 fS at pHi 6.5, and increased nearly fourfold to 140 fS at pHi 5.5, but was independent of pHo. In contrast, the macroscopic gH was only 1.8-fold larger at pHi 5.5 than at pHi 6.5. The maximum H+ channel open probability during large depolarizations was 0.75 at pHi 6.5 and 0.95 at pHi 5.5. Because the unitary conductance increases at lower pHi more than the macroscopic gH, the number of functional channels must decrease. Single H+ channel currents were too small to record directly at physiological pH, but at pHi ≤ 5.5 near Vthreshold (the voltage at which gH turns on), single channel–like current events were observed with amplitudes 7–16 fA.
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ROMANJEK, KRUNOSLAV, GÉRARD GHIBAUDO, THOMAS ERNST, and JAN A. CHROBOCZEK. "LOW FREQUENCY NOISE IN SUB-0.1μmSiGepMOSFETs, CHARACTERISATION AND MODELING." Fluctuation and Noise Letters 04, no. 02 (June 2004): L309—L318. http://dx.doi.org/10.1142/s0219477504001914.
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Drain current-gate voltage, I d ( V g ) characteristics and the power spectral density, PSD , of I d fluctuations were obtained on SiGe channel pMOSFETs and on their Si homologues, for I d intensities varied from deep sub-threshold to strong inversion values. Devices with 2.2nm thick SiO 2 gates and channel lengths 50 nm <L<10μm were used. In heterostructures, the SiGe layers were 20nm thick and buried under 2nm of Si . The data were simulated, assuming a parallel current flow in the interface and the SiGe channels, with associated noise sources. The transport parameters, extracted from I d ( V g ) characteristics, served for calculating the PSD ( I d ) functions. The latter required adjusting the interface trap density and a parameter α c , accounting for the effect of the interface charge fluctua-tions on the hole mobility fluctuations, significant at high levels of trap filling i.e. high I d . We found that the PSD in the SiGe devices was up to 10 times lower than in the Si controls at sufficiently high I d . The simulation, accounting for the data, required a significant lowering of α c for the SiGe channel. That implies that the LFN reduction in SiGe MOSFETs results from a weaker interaction of the SiGe holes with the interface charges. The sub-0.1μm channel devices show a similar noise lowering, in spite of the hole mobility degradation.
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Chatterjee, Abhijit, Amardeep Jagtap, Naresh Pendyala, and K. S. R. Koteswara Rao. "HgCdTe Quantum Dot Over Interdigitated Electrode for Mid-Wave Infrared Photon Detection and Its Noise Characterization." International Journal of Nanoscience 19, no. 03 (December 20, 2019): 1950020. http://dx.doi.org/10.1142/s0219581x19500200.
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In this paper, we report the development of mid-wave infrared (MWIR) photon sensor using solution-processed mercury cadmium telluride (Hg[Formula: see text]CdxTe) semiconductor colloidal quantum dots (CQDs) coated over interdigitated metallic electrode structure, having significant response in the MWIR spectral band range ([Formula: see text]–5.0[Formula: see text][Formula: see text]m) at room temperature. HgCdTe CQD has been chemically synthesized. We have characterized the optical and [Formula: see text] noise performances of the developed sensor to understand its behaviors at different operating biases as an introductory step toward development of large-format MWIR focal-plane arrays having similar pixel structure. The optimum biasing conditions have been experimentally evaluated at room temperature. We have achieved a noise equivalent power (NEP) of 2.5[Formula: see text]pW at 1.5-V bias voltage which corresponds to detectivity ([Formula: see text]) in the order of 108. This work highlights the development of low-cost colloidal HgCdTe quantum dot photodetectors and their utility in the monolithic infrared focal-plane arrays.
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Azadbakht, Mostafa, Ali Sahafi, and Esmaeil Najafi Aghdam. "A Dual Band Fractional-N Frequency Synthesizer with a Self-Calibrated Charge Pump for WLAN Standards." Journal of Circuits, Systems and Computers 27, no. 08 (April 12, 2018): 1850131. http://dx.doi.org/10.1142/s0218126618501311.
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This work presents a fully integrated fractional-[Formula: see text] frequency synthesizer that covers the entire frequency bands specified in the IEEE 802.11 a/b/g/n. In this paper, the effects of charge pump (CP) gain mismatch on spectral purity of local oscillator signal is studied theoretically and a new high precision self-calibrated CP is presented for alleviating the nonidealities. The idea is implemented in a 0.18-[Formula: see text]m standard CMOS technology. According to post layout simulation, the proposed calibration circuit demonstrates an excellent matching in the CP currents in a wide voltage range. By using this technique, the average of close-in phase noise of the designed frequency synthesizer is suppressed by more than 12[Formula: see text]dBc. The active whole chip die area is 0.475[Formula: see text]mm2 and the power dissipation from a 1.8-V DC supply is 17.3–20.6[Formula: see text]mW.
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SOLIMAN, AHMED M. "HISTORY AND PROGRESS OF THE TOW–THOMAS BIQUADRATIC FILTER PART II: OTRA, CCII, AND DVCC REALIZATIONS." Journal of Circuits, Systems and Computers 17, no. 05 (October 2008): 797–826. http://dx.doi.org/10.1142/s0218126608004691.
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The realization of the Tow–Thomas (TT) circuit using the Operational Transresistance Amplifier (OTRA) is reviewed. The circuit employs two OTRA, and all passive elements are floating as the original Tow–Thomas circuit. The Current Conveyor (CCII) TT circuits are reviewed next. The progress in the realization of the TT circuit using CCII is demonstrated clearly by summarizing eight different circuits. One of the circuits has the advantage of very high input impedance using all grounded resistors and capacitors. The Differential Voltage Current Conveyor (DVCC) as the active building block in realizing the TT circuit is also considered. Finally, current mode TT circuits using balanced output CCII are summarized. Top Spice (level 49), simulation results using technology SCN 05 feature size 0.5 μm from MOSIS vendor: AGILENT are included to demonstrate the magnitude and phase frequency response of the TT circuits. Additional simulation results for the total power dissipation, total harmonic distortion, intermodulation IM3, input and output referred noise spectral densities are also included for comparison purposes.
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Stadler, Adam Witold, Andrzej Kolek, Krzysztof Mleczko, Zbigniew Zawiślak, Andrzej Dziedzic, and Wojciech Stęplewski. "Noise sources in polymer thick-film resistors." Soldering & Surface Mount Technology 27, no. 3 (June 1, 2015): 115–19. http://dx.doi.org/10.1108/ssmt-04-2015-0014.
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Purpose – The paper aims to get the knowledge about electrical properties, including noise, of modern polymer thick-film resistors (TFRs) in a wide range of temperature values, i.e. from 77 K up to room temperature. The sample resistors have been made of different combinations of resistive compositions, either ED7100 or MINICO (M2013, M2010), and conducting pastes (for contacts) Cu- or Au-based, deposited on FR-4 laminate. Design/methodology/approach – The paper opted for an experimental study using either current noise index measurement in room temperature for large batch of samples or noise spectra measurement in temperature range 77-300 K for selected samples. Obtained noise maps, i.e. plots of power spectral density of voltage fluctuations vs frequency and temperature, have been used for evaluation of noise describing parameters like material noise intensity C and figure of merit K, for TFRs made of different combinations of resistive/conductive materials. Comparison of the parameters gives the information about the quality of the technology and matching the conductive/resistive materials. Findings – Experiments confirmed that the main noise component is 1/f resistance noise. However, low-frequency noise spectroscopy revealed that also noise components of Lorentzian shape, associated with thermally activated noise sources exist. Their activation energies have been found to be of a few tenths of eV. Research limitations/implications – The noise intensity of polymer TFRs depends on technology process and/or contacts materials. The use of Au contacts leads to better noise properties of the resistors. The results of the studies might be helpful for further improvement of thick-film technology, especially for manufacturing low-noise, stable and reliable TFRs. Practical implications – The paper includes indications for the materials selection for thick-film technology to manufacture low-noise, reliable and stable TFRs. Originality/value – Experimental studies of electrical properties of polymer TFRs by means of noise spectra measurements in wide range of temperature is rare. They give fundamental knowledge about noise sources in the modern passive electronic components as well as practical indications of selection material for thick-film technology, to obtain high performance components and get technological advantage.
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Noskov, M. Yu, M. M. Ginshparg, and N. S. Nesterov. "Results of tests on the indicator of external noise of electric locomotives in the standing time." Vestnik of the Railway Research Institute 76, no. 5 (October 28, 2017): 301–5. http://dx.doi.org/10.21780/2223-9731-2017-76-5-301-305.
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The authors of the Test Loop of the JSC “VNIIZhT” had conducted tests of mainline electric locomotives intended for handling freight trains on sections of the road electrified with alternating current at a voltage of 25 kV (electric locomotives of an alternating current). Tests were conducted in terms of the level of external noise at the standing time. The results of tests of AC electric locomotive, which was in a stationary mode, are presented in terms of the external noise index, and a methodology for performing these tests is described. As a result of the conducted researches, the article establish the main sources of external noise in the operation of AC electric locomotives (fans intended for cooling electrical equipment and traction motors, air compressors, traction transformers, etc.), its actual values, as well as the nature of the sound field around electric locomotives. The analysis of the obtained sound field made it possible to identify the points where the excess of the standard noise values (more than 65 dBA) is observed. It is proposed to bring the technical condition of the equipment, such as traction transformer, converter and cooling module of the traction engine of the power compartment of an electric locomotive in accordance with the normative documentation. The repeated measurements of the external noise level after technical completion did not reveal the excess of its normative values in accordance with the regulatory documentation. In order to provide a normative margin in terms of the external noise of an electric locomotive, it is proposed to use sound-absorbing material in the construction of its body. It is recommended to perform an experimental study of the spectral composition of the noise of the equipment of an electric locomotive operating at the standing time and the resulting external noise at points located outside and around the locomotive in order to calculate the acoustic characteristics of sound-absorbing materials. Sound absorbing material is expedient to be selected depending on the frequency range in which the greatest excess is observed above the maximum permissible values using known empirical and semi-empirical dependences, on the basis of which it is possible to preliminary determine its sound-absorbing properties in the frequency range established by regulatory documents. After equipping the power compartment of the locomotive with soundproof materials, tests on the evaluation of the external noise of an electric locomotive at standing should be repeated.
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Dobrovolsky, V. N. "Generation of the current normal to the surface of antenna by electromagnetic waves and its application in the high responsive receiver." Semiconductor Physics, Quantum Electronics and Optoelectronics 24, no. 1 (March 9, 2021): 76–82. http://dx.doi.org/10.15407/spqeo24.01.076.
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Generation of the initial current normal to the surface of antenna by electromagnetic waves has been considered. It has been shown that the angle of grazing (or sliding) for the wave with the electric vector in the plane normal to the surface varies the radiation resistance over a wide range. This property allows matching the radiation impedances and loads. Here, it has been proposed to use this property to create a highly- sensitive radiation detector. In relation with this task, a model of the radiation detection of the input radiation signal by a direct quadratic detector in the stationary mode with the diode included as the load has been considered. The obtained results prove that a diode with the high differential resistance can effectively operate with the antenna. The rise of the resistance increases the detector response voltage, its responsivity, and decreases the receiver noise equivalent power. Improvement of these characteristics by orders of magnitude is possible. The considered mechanism allows detectors to operate in the infrared spectral range, and the increase in the wavelength, in principle, does not limit its functioning.
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Maheswari, R. V., B. Vigneshwaran, and L. Kalaivani. "Genetic algorithm based automated threshold estimation in translation invariant wavelet transform for denoising PD signal." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, no. 4 (July 6, 2015): 1252–69. http://dx.doi.org/10.1108/compel-12-2014-0332.
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Purpose – The purpose of this paper is to investigate the condition of insulation in high-voltage equipments using partial discharge (PD) measurements. It proposes the methods to eliminate several noises like white noise, random noise and discrete spectral interferences which severely pollutes the PD signals. The study aims to remove these noises from the PD signal effectively by preserving the signal features. Design/methodology/approach – This paper employs fast Fourier transform, discrete wavelet transform and translational invariant wavelet transform (TIWT) for denoising the PD signals. The simulated damped exponential pulse and damped oscillatory pulse with low- and high-level noises and a measured PD signal are considered for this analysis. The conventional wavelet denoising approach is also improved by estimating the automated global optimum threshold value using genetic algorithm (GA). The statistical parameters are evaluated and compared. Among these methods, GA-based TIWT approach provides robustness and reduces computational complexity. Findings – This paper provides effective condition monitoring of power apparatus using GA-based TIWT approach. This method provides the low value of mean square error, pulse amplitude distortion and also high reduction in noise level due to its robustness and reduced computational complexity. It suggests that this approach works well for both signals immersed in noise as well as for noise immersed in signals. Research limitations/implications – Because of the chosen PD signals, the research results may lack for multiple discharges. Therefore, researchers are encouraged to test the proposed propositions further. Practical implications – The paper includes implication for the development of online testing for equipment analysis and diagnostics during normal operating condition. Corrective actions can be planned and implemented, resulting in reduced unscheduled downtime. Social implications – This PD-based analysis often present well in advance of insulation failure, asset managers can monitor it over time and make informed strategic decisions regarding the repair or replacement of the equipment. These predictive diagnostics help society to prioritize investments before an unexpected outage occurs. Originality/value – This paper provides an enhanced study of condition monitoring of HV power apparatus by which life time of insulation can be increased by taking preventive measures.
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Jaquez-Muñoz, Jesus, Citlalli Gaona-Tiburcio, Alejandro Lira-Martinez, Patricia Zambrano-Robledo, Erick Maldonado-Bandala, Oliver Samaniego-Gamez, Demetrio Nieves-Mendoza, Javier Olguin-Coca, Francisco Estupiñan-Lopez, and Facundo Almeraya-Calderon. "Susceptibility to Pitting Corrosion of Ti-CP2, Ti-6Al-2Sn-4Zr-2Mo, and Ti-6Al-4V Alloys for Aeronautical Applications." Metals 11, no. 7 (June 23, 2021): 1002. http://dx.doi.org/10.3390/met11071002.
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Titanium alloys are used in different industries like biomedical, aerospace, aeronautic, chemical, and naval. Those industries have high requirements with few damage tolerances. Therefore, they are necessary to use materials that present fatigue, mechanical, and corrosion resistance. Although Ti-alloys are material with high performance, they are exposed to corrosion in marine and industrial environments. This research shows the corrosion behavior of three titanium alloys, specifically Ti CP2, Ti-6Al-2Sn-4Zr-2Mo, and Ti-6Al-4V. Alloys were exposed on two electrolytes to a 3.5 wt % H2SO4 and NaCl solutions at room temperature using cyclic potentiodynamic polarization (CPP) and electrochemical noise (EN) according to ASTM G61 and ASTM G199 standards. CPP technique was employed to obtain electrochemical parameters as the passivation range (PR), corrosion type, passive layer persistence, corrosion potential (Ecorr), and corrosion rate. EN was analyzed by power spectral density (PSD) in voltage. Results obtained revealed pseudopassivation in CPP and PSD exposed on NaCl for Ti-6Al-2Sn-4Zr-2Mo, indicating instability and corrosion rate lower. However, Ti-6Al-4V presented the highest corrosion rate in both electrolytes. Ti-6Al-2Sn-4Zr-2Mo revealed pseudopassivation in CPP and PSD in NaCl, indicating a passive layer unstable. However, the corrosion rate was lower in both solutions.
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"Noise Power Spectral Density Analysis for Silicon Carbide Substrate MESFET." International Journal of Innovative Technology and Exploring Engineering 8, no. 11 (September 10, 2019): 1409–12. http://dx.doi.org/10.35940/ijitee.j9759.0981119.
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This paper mainly concentrates on the transistors working functions, electrical characteristics and noise analysis at various operating voltages and temperatures. For this improvement authors are developed simulation methods for better results. The high frequency transistors are exposed with bunch of silicon carbide crystalline substances like 3C, 4H and 6H-SiC MESFETs. Because of the good researchers work, now a day’s all are compared the parameter in between of cubic and hexagonal crystalline structure of silicon carbide MESFETs. Silicon carbide material is having wide band gap because of this reason it’s useful for high energy and high frequency applications. The silicon carbide transistors are having large operating voltage in channel region because of this reason in channel region flows large current and also very less noise is produced. In wide band gap semiconductor transistors are produced very less noise compared to the various categories of substrates.
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Chan, Jack, Brian G. Burke, Chong Hu, Joe Campbell, Lloyd Harriott, and Keith A. Williams. "Electron Beam Induced Two-State Noise in Carbon Nanotubes." MRS Proceedings 1204 (2009). http://dx.doi.org/10.1557/proc-1204-k18-10.
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AbstractDiscrete current switching is induced in carbon nanotubes by electron beam irradiation. Switching amplitudes of 3% to 6% are observed at room temperature. Switching is created by electron beam exposure with dosage as low as 1000 pC/cm. Relative switching amplitude remains constant as the bias voltage varies, suggesting that current fluctuation is dominated by mobility fluctuation. Changes in the noise power spectral density following electron beam exposure will be discussed.
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He, Wangling, Baoquan Wan, Yunpeng Liu, Xingfa Liu, Shilong Huang, Yinlu Zhang, and Jiangong Zhang. "Audible noise spectral characteristics of high‐voltage ac bundled conductors at high altitude." IET Generation, Transmission & Distribution, December 30, 2020. http://dx.doi.org/10.1049/gtd2.12103.
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Jha, Shrawan K., Bun H. Leung, Charles C. Surya, Heins Schweizer, and Manfred H. Pilkhuhn. "Low-Frequency Noise Characterization in AlGaN/GaN HEMTs with Varying Gate Recess Depths." MRS Proceedings 831 (2004). http://dx.doi.org/10.1557/proc-831-e8.31.
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ABSTRACTLow-frequency noise measurements were performed on a number of AlGaN/GaN HEMTs with different gate recess depths, which were formed by dry etching. Detailed characterizations of the low-frequency noise properties were performed on the devices as a function of as a function of hot-electron stressing conducted at VD = 10 V and VG = -1.5 V. The room temperature voltage noise power spectral density, SV(ƒ), of the devices were found to show 1/ƒ dependence. A comparison of SV(ƒ) measured from different devices clearly indicate increase in the noise levels for the devices with large recess depths, reflecting the degradation caused by ion-impact induced damage during recess formation. Furthermore, the results of low-frequency noise measurements showed fast degradations for the devices with larger gate recess depths. Our experimental data clearly show that the dry etching process has induced damages in gates.
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Yu, Jianhai, Liang Yin, and Changchun Dong. "A novel 2.5 Gbps pre-transimpedance amplifier with the gain adaptively adjusted." Modern Physics Letters B, April 20, 2021, 2140003. http://dx.doi.org/10.1142/s0217984921400030.
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A 2.5 Gbps transimpedance amplifier (TIA) with the feedback resistance self-adaptively adjusted is designed for the application of optical receivers in passive optical network and implemented in Global Foundries (GF) 0.18 [Formula: see text]m CMOS standard process. The main structure of the circuit consists of an improved three-stage current multiplexing push-pull inverter. With the diode-connected-transistor placed at each end of the inverter, the extra pole will be pulled away in order to increase the stability of the loop system. The feedback resistance of TIA is connected in parallel with the NMOS transistor, and the gate voltage of the tube is adjusted automatically to control the resistance value of this parallel structure in order to overcome the defect of the inverter which will work in the linear region on the condition of excessive optical power. A low-dropout linear regulator (LDO) is adopted from the power supply to the TIA to isolate power supply noise. The measured results demonstrate that the fabricated TIA with a photodetector capacitance of 3.2 pF has a transimpedance gain of 41.64 dB[Formula: see text] with a current signal frequency of 2.5 Gbit/s, and a −3 dB bandwidth of 2.35 GHz. The average input-referred noise current spectral density within the bandwidth is185 pA/Hz[Formula: see text], signal rise time is 195 ps, fall time is 227 ps, eye diagram height is 28 mV, optical sensitivity is −30.6 dBm, and power consumption is only 52 mW at 3.3 V power supply voltage, the chip area is [Formula: see text] mm2.
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Akinci, Tahir Cetin, and Winston Chung. "Determination of isolator damages in electric power transmission lines with continuous wavelet transform and multitape power spectrum density." World Journal of Science, Technology and Sustainable Development ahead-of-print, ahead-of-print (July 28, 2021). http://dx.doi.org/10.1108/wjstsd-05-2021-0059.
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PurposeDetection of deformation of devices in high voltage electricity transmission line systems is an important issue in terms of economy and reuse. This study is aimed to detect devices that are deformed or thought to have suffered due to environmental and electrical reasons.Design/methodology/approachIn this experimental study, it was ensured that the sound and deformed insulators used in energy transmission lines were determined by the analysis of the sounds obtained by using the impact method. Equal intensity impact was applied to the isolator using the pendulum and the resulting sound noise signal analyses were made using power spectral density (PSD), magnitude scalogram (MS), multitape power spectrum density (MPSD) and continuous wavelet transform (CWT) methods in the study. In the analysis results, the isolators that are not visible to the eye and have certain damage were successfully separated from the intact insulators. Especially, MPSD and CWT analysis results are quite satisfactory.FindingsDamage analysis of insulators used in electricity transmission lines has been made. A total of 40 insulators were examined in two categories in their group, both damaged and not damaged. Data collection system was established. The data obtained from the data collection system were analysed and compared using four analysis methods. PSD, MS, MPSD and CWT analyses were made in the study. All the analyses carried out generally contain features that distinguish damaged and undamaged insulators from each other, the most successful results are MS and CWT results. CWT results are very successful in terms of time and amplitude, and it has been proposed as a method that can be used to separate damaged and undamaged insulators.Originality/valueIt can be suggested as a result of experimental tests that the results of CWT analysis can be used in the pulse noise method in isolators to be tested for reuse in electrical power transmission lines.
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Ke, Lin, Sha Huang, Soo Jin Chua, Szu Cheng Lai, and Bin Dolmanan Surani. "Minority Carrier Lifetime Measurement Based on Low Frequency Fluctuation." MRS Proceedings 1195 (2009). http://dx.doi.org/10.1557/proc-1195-b09-04.
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AbstractWe present a novel, simple, and accurate approach based on low frequency voltage fluctuations to determine the averaged carrier lifetime in semiconductor materials and devices. This technique serves to address the limitations faced by existing techniques that use light as the excitation source for lifetime measurement. In this paper, the minority carrier lifetime is inferred from the 1/f low frequency noise profile exhibited by the device during low current operation. The current dependence of the power spectral density and its relation to minority carrier lifetime is modeled and derived directly giving a current dependent carrier lifetime. This technique is solely based on the electrical noise and no light source is required for excitation. The low frequency noise can be easily acquired without significant distortion via a signal analyzer as long as there is a sufficiently good Ohmic contact between the probe and the device under test, and that the device is sufficiently shielded from the influence of EMI. This technique has lower crosstalk, fewer fitting parameters, is low cost and allows the lifetime to be extracted directly from data collected at lower frequencies. These characteristics make our method useful in encapsulated devices, applicable on wafers and devices in
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Belich, T. J., Z. Shen, C. Blackwell, S. A. Campbell, and J. Kakalios. "Conductance Fluctuations in Amorphous Silicon Nanoparticles." MRS Proceedings 862 (2005). http://dx.doi.org/10.1557/proc-862-a4.1.
Full textAbstract:
AbstractHydrogenated amorphous silicon nanoparticles with an average diameter of 150 nm have been synthesized by high-density plasma chemical vapor deposition. The particles are deposited onto a conducting substrate and are then surrounded by an insulating matrix, electrically isolating the particles. Electrical contact is made to the top of each nanoparticle; the current-voltage characteristics of the nanoparticles indicate that transport is space-charge limited through the a-Si:H. The spectral density of the current fluctuations in the a-Si:H nanoparticles is well described by a 1/f frequency dependence for frequency f. However, the octave separation dependence of the correlation coefficients of the noise power for the nanoparticles are very well described by an ensemble of fluctuators whose amplitudes are independently modulated in parallel, rather than the serial kinetics typically observed in bulk a-Si:H.
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Hong, Hyesook, Wayne A. Anderson, Eunwha Lee, Huicheng Chang, Myunghee Na, and Hong Luo. "Low Temperature Processed Metal-Semiconductor-Metal Phtodetectors on ZnSe/SI-GaAs (100)." MRS Proceedings 487 (1997). http://dx.doi.org/10.1557/proc-487-523.
Full textAbstract:
AbstractLow temperature (LT) processed ZnSe MSM photodetectors can be used for detecting Gamma rays or X-rays using scintillation crystals in many space and medical applications. Metalsemiconductor-metal (MSM) photodetectors were fabricated on undoped ZnSe grown by molecular beam epitaxy (MBE) on semi-insulating (100) GaAs substrates. The MSM photodetectors consist of interdigitated metal fingers with 2 μm, 3 μm, and 4 μm spacing on one chip. Probimide and SiO2 thin films were deposited to aid the LT lift-off process before the pattern generation. An interdigitated structure was achieved by photolithography and reactive ion etching. Pd Schottky metal was deposited at a substrate temperature near 77 K using a lift-off technique. The LT metallization provides an improved interface between metal and semiconductor interface. Continuous wave signal to noise ratio (SNR) of 1.57×104 was obtained for 2 μm interdigitated photodetectors, operated under 180 nW optical power at a wavelength of 400 nm. The detectors showed good DC saturation characteristics indicating a low surface recombination. Saturation current without illumination remained at around less than 1 pA for a ± 10 V biasing. Detectors exhibited linearity with light intensity and DC bias voltage suggesting no gain mechanism involved, and showed a high spectral responsivity (0.6 (A/W)) at a wavelength of 450 nm at 5V applied bias.
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"Properties of membrane ion conductances evoked by hormonal stimulation of guinea-pig and rabbit isolated hepatocytes." Proceedings of the Royal Society of London. B. Biological Sciences 236, no. 1283 (March 22, 1989): 187–201. http://dx.doi.org/10.1098/rspb.1989.0020.
Full textAbstract:
Membrane conductance changes evoked in isolated guinea-pig or rabbit hepatocytes by hormonal stimulation were studied with the whole-cell patch clamp technique. In Cl-containing solutions, noradrenaline (NA), ATP or angiotensin II (All) evoked an increase of conductance to both K ( G K ) and Cl ( G CI ) ions. Activation of G K occurred after a delay of several seconds and was sustained in the presence of hormone. Activation of G CI was transient, lasting several seconds, and arose either at the same time or shortly after the increase in G K . Conductances showed an initial rapid rise and slow oscillatory changes during maintained hormone application. The NA-induced current reversed at –19 mV in Cl solutions, between the equilibrium potentials for chloride ( E CI = 0 mV) and potassium ions ( E K = –85 mV), and at –75 mV, near E K , in Cl-free solution. In both conditions whole-cell current-voltage curves were linear in the range –100 mV to +40 mV. The conductance increase produced by NA to Cl - ions was about 50 nS, that to K + ions was 6 nS. The potassium conductance increase was abolished by the polypeptide toxin apamin (50 nM). An increase in membrane current noise was associated with NA-evoked outward K - current and blocked by apamin. Spectral analysis gave estimates of the elementary K channel conductance of 1.7 pS. Power spectra were fitted by two Lorentzian components, with average half-power frequencies of 2 and 190 Hz. These results are discussed in relation to the single-channel properties and indicate that the open probability of K channels during the NA response is high. In Cl solutions, with apamin to block the K conductance, no increase in current noise was detected during the large Cl conductance evoked by NA. This suggests either that Cl channels are of very low unitary conductance (less than 1 pS) or that Cl transport is due to a membrane carrier. The complex time-course of hormonally evoked conductances is not due to the properties of ion conductances per se but probably to underlying changes of intracellular second-messenger concentration.