Voltage Noise Research Articles

Total Ionizing Dose Effects on Solar-Blind Ultraviolet Focal Plane Arrays

The study of the effect of γ-rays on the characteristic parameters of the AlGaN ultraviolet focal plane arrays (UVFPA) was carried out to address the problem of degradation of the characteristic parameters of the solar-blind UVFPA after irradiated by energetic particles in the space environment. The AlGaN UVFPA was irradiated with 60Co γ-rays and annealed at room temperature after irradiation. The dark current, noise voltage, responsivity, detectivity, and other characteristics of the UVFPA were compared before and after irradiation and annealing to summarize the changes of the UVFPA characteristics and to analyze the radiation effect mechanism of AlGaN UVFPA. The experimental results show that as irradiation dose increases, the dark current increases, and the responsivity decreases. After annealing of irradiated sample at room temperature, the degradation of the characteristic parameters caused by irradiation is restored. We believe that the effect of ionizing radiation leads to the increase of leakage current in MOS transistor and threshold voltage drift, resulting in the change of the UVFPA operating point and degradation of the characteristic parameters.

A Proposed On-Die Oscilloscope for Monitoring of Power Noise Waveform Inside IC Due to Transient Stress Events

An on-die oscilloscope circuit is proposed to monitor the power noise waveforms inside IC due to the transient stress events for a more complete analysis of the effects of the transient stress events on the electronic systems. When the transient stress event occurs, the induced noise voltage waveform in the power supply is sampled and converted to digital data in real time. A trigger signal created by the event detector circuit is used to hold the digital data. The stored digital data inside the on-die oscilloscope are reconstructed back to the analog noise waveform based on the sampling process. The operation of each circuit block in the on-die oscilloscope is analyzed and validated by simulation and measurement results. The approximate bandwidth of the proposed on-die oscilloscope is extracted from simulation results. The power noise waveforms due to the transmission line pulse events and electrostatic discharge events are measured with an external oscilloscope instrument using cables and directly sampled and reconstructed by the on-die oscilloscope, and these measured and reconstructed analog noise waveforms are compared with each other.

A broadband detector based on series YBCO grain boundary Josephson junctions.

Modeling of a broadband receiving system based on a meander series of Josephson YBaCuO grain boundary junctions integrated into a log-periodic antenna was carried out. The electromagnetic properties of the system, namely amplitude–frequency characteristic, beam pattern, and fraction of the absorbed power in each Josephson junction were investigated. Based on the obtained results, a numerical simulation of one-dimensional arrays was carried out. The dc characteristics of the detector were calculated, that is, current–voltage characteristic, responsivity, noise, and noise-equivalent power (NEP) for a 250 GHz external signal. The optimal number of junctions to obtain the minimum NEP was found. The use of a series of junctions allows one to increase the responsivity by a factor of 2.5, the NEP value by a factor of 1.5, and the power dynamic range by a factor of 5. For typical YBaCuO Josephson junctions fabricated on a ZrYO bicrystal substrate by magnetron deposition, the following parameters were obtained at a temperature of 77 K: responsivity = 9 kV/W; NEP = 3·10−13 W/Hz(1/2); power dynamic range = 1·106.

Improvement of the detectivity in an Fe–Sn magnetic-field sensor with a large current injection

A ferromagnetic nanocrystalline Fe–Sn is an excellent platform for magnetic-field sensor based on anomalous Hall effect (AHE) owing to simple fabrication and superior thermal stability. For improvement of the magnetic-field sensitivity, doping impurity and increasing injection current are effective approaches. However, in the light of magnetic-field detectivity, the large current may increase the voltage noise. In this study, a maximum allowable current was improved by employing the overlayer electrode configuration on a Ta-doped Fe–Sn AHE sensor. In noise measurements, the 1/f noise becomes significant with increasing the current at low frequency, resulting in saturation of the detectivity to 240 nTHz−1/2 at 120 Hz. At high frequency, the detectivity reaches 48 nTHz−1/2 at 3.1 mA showing ten times improvement of the detectivity compared with the non-doped Fe–Sn AHE sensor. Material design and device structure optimization will accelerate further improvement of the sensing properties of the Fe–Sn-based AHE sensor.

Mechanisms of the end-plate potential noise and its implication for the neuromuscular junction anatomy

We construct a compact model to mimic the membrane voltage response to the concentration of acetylcholine ([ACh]) which is mediated by the stochastic gating of acetylcholine (ACh) receptors. The patterns of the voltage depolarization against [ACh] as well as the accompanying voltage noises are presented. The mechanism of the voltage fluctuation that caused by the stochastic gating of receptors is explained. We consider that our results explain the frequently observed “end-plate (potential) noise” in physiology and electromyographic literature. These results, together with the requirements of evolution pressure on the motor units, explain reasonably the anatomical structure of the neuromuscular junction.

A Closed-Form Transient Response of Coupled Transmission Lines

There is a growing interest in analysis of crosstalk noise and delay in coupled transmission lines in various fields. Due to the large number of interconnections and associated compression, this analysis is particularly significant in large integrated circuits. There are various ways to analyze crosstalk noise and delay considering the compromise between accuracy and complexity. This article presents closed-form expressions in the Laplace domain based on transmission line theory to obtain crosstalk noise and delay of identical and nonidentical coupled interconnections. To this end, a simple model is proposed, which encompasses both capacitive and inductive coupling features in coupled interconnections. Moreover, it serves to handle both functional and dynamic crosstalk. The crosstalk noise voltage and propagation delay at the far-end of coupled lines are observed. The transient response of coupled transmission lines is demonstrated for various case studies. The obtained results are compared with Advanced Design System simulations indicating that the proposed model computes crosstalk noise and captures waveform shapes with desired accuracy. Moreover, the derived form is scalable for the analysis of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> coupled multiconductors, opening new horizons to analyze the complex integrated circuit interconnections with decent accuracy and high computation speed.

Statistical Random Number Generator Attack Against the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange Protocol

This paper introduces and demonstrates four new statistical attacks against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange scheme. The attacks utilize compromised random number generators (RNGs) at Alice’s/Bob’s site(s). The case of partial correlations between Alice’s/Bob’s and Eve’s probing noises is explored, that is, Eve’s knowledge of Alice’s and Bob’s noises is limited but not zero. We explore the bilateral situation where Eve has partial knowledge of Alice’s and Bob’s RNGs. It is shown that in this situation Eve can crack the secure key bit by taking the highest cross-correlation between her probing noises and the measured voltage noise in the wire. She can also crack the secure key bit by taking the highest cross-correlation between her noise voltages and her evaluation of Alice’s/Bob’s noise voltages. We then explore the unilateral situation in which Eve has partial knowledge of only Alice’s RNG thus only those noises (of Alice and Eve) are correlated. In this situation, Eve can still crack the secure key bit, but for sufficiently low error probability, she needs to use the whole bit exchange period for the attack. The security of the KLJN key exchange scheme, similarly to other protocols, necessitates that the RNG outputs are truly random for Eve.

A 13.42ps Resolution, Low-Power Time-to-Digital Converter and 0.519fJ Energy-Efficient Novel Voltage-to-Time Converter for High-Speed Time-Based ADC Application

Voltage domain ADC architectures require high gain and high bandwidth opamps to amplify the signal for successive stages. The opamp design gets a bit challenging due to noise, small gain and lower overdrive voltage. Due to these limitations, the inclination shifted towards high-speed converters which don’t require opamps. Time based Analog to Digital Converters (TBADC) is one such category of circuits. TBADCs are constituted from VTC followed by TDC with an encoder in the end. This work is concerned around the design of a high-resolution time to digital converter (TDC) and proposing a novel high-speed, low power consuming voltage to time converter (VTC) circuit. Both the circuits were implemented in Cadence Virtuoso EDA tool version 6.1.7 and Spectre was employed for running the simulations. TDC circuits had resolution of 13.425 ps and consume power of 1.873 μW. Process corner analysis and Monte Carlo analysis were performed on VTC design to determine worst possible deviations in performance. The proposed VTC exhibited delay of 23.79 ps with power consumption of 21.83 μW at 1 Volt. The presented TDC and VTC circuits can be used to design high-speed time-based Analog to Digital Converters.

Solar cell parameter accuracy improvement, via refinement of the Co-Content function. Part 1: theoretical analysis

In this Part 1 of this series of articles, the accuracy on the obtention of the shunt resistance (R sh ), the series resistance (R s ), the ideality factor (n), the light current (I lig ), and the saturation current (I sat ), via the use of the Co-content function (where ) is investigated theoretically, as function of the number of measured points per voltage () and percentage noise (). Reasonable values are obtained for R sh , R s , and I lig , with = 11 measurement points per V if the is 0.1% or less. For a reasonable determination of n at least = 101 measurement points per V are needed. I sat determination requires of 0.01% or lower with at least = 101 measured points per V and should be evaluated at large values of V. The results given in this Part 1 are used in Part 2 to discuss the reported application of the to obtain R sh , R s , n, I lig , and I sat found in the literature.

Thermal noise of hot carriers under natural sunlight

The efficiency of hot carrier solar cells strongly depends on the attainable carrier temperature in the absorber material. Measurements of hot carrier temperature under natural concentrated sunlight were performed at thin films of graphite, bismuth and PbTe, cooled through AlN ceramic substrate. The carrier temperature was assessed by magnitude of thermal noise voltage of charge carriers in the frequency range between 300 and 20,000 Hz according to Nyquist formula. Noise measurement equipment was calibrated in a range of sample impedances by using heated metal film resistors. We found that the carrier temperature in graphite films can exceed 600 °C under up to 15,000× suns and is much higher than the estimated lattice temperature in the film under the given cooling conditions. Secondary electron micrographs illustrate a good mechanical contact between the graphite film and the AlN substrate. We found also distinct heating of charge carriers in PbTe up to about 100 °C. Contrary to that, no measurable carrier heating above the lattice temperature was detected in bismuth films. Johnson noise thermometry demonstrates potential in identification of attractive candidate materials for absorbers in hot carrier solar cells.

Method for onsite measurement of common-mode voltage of conducted noise based on shoe-shaped wearable sensors

This paper proposes a method for the onsite measurement of the common-mode voltage of conducted electromagnetic noise in data transmission cables without direct contact with the reference ground of the noise to be measured. The return path of the noise is a capacitive coupling between an electrode and the floor of the measurement site. The capacitive coupling is evaluated by applying a radio-frequency signal to an electrode facing the floor and measuring the amplitude at another electrode placed adjacent to the former electrode. These electrodes and measurement circuits are installed in the soles of shoe-shaped wearable sensors. Furthermore, instead of attaching a probe to a transmission cable, the maintenance engineer grasps the cable by hand. The noise in the cable passes through the capacitive coupling between the cable and the hand, through the human body, and through the capacitive coupling between the bottom electrode in the shoes and the floor. The noise voltage between the two electrodes in the sensor shoes is measured. The actual noise voltage and the measured voltage at various capacitive coupling levels and frequencies are recorded prior to the actual measurement at the site and their relationship is expressed by empirical formulas. The measurement system was evaluated at three typical office floors that had different floor structures. In all cases, the error between the actual noise voltage in the cable and the estimated voltage obtained by the proposed system was less than 1.33 dB. The results indicate that the proposed method can be used to quantitatively measure the common-mode voltage of conducted noise in a real-world environment.

Solar cell parameter accuracy improvement, via refinement of the Co-Content function. Part 2: Discussion on the experimental application

In this Part 2 of this series of articles, a discussion of the literature reported obtention of the solar cell parameters (the shunt resistance (R sh ), the series resistance (R s ), the ideality factor (n), the light current (I lig ), and the saturation current (I sat )), via the use of the Co-content function (where ) is given. The results reported in Part 1, namely, the accuracy dependence of the determination of R sh , R s , n, I lig , and I sat , as a function of the number of measured points per voltage () and percentage noise () is used to analyse the reported solar cell parameters. In one case, the application of to solar panels is discussed, revealing that it can also be used in the case of solar panels, and not only for laboratory-made solar cells, in voltage ranges larger than [0 V, 1 V]. In another case, the application of to IV curves showing the roll-over effect is discussed. It is found that the roll-over effect has a pernicious effect in the solar parameter extraction, and then the should be calculated before the roll-over effect takes place. In a third case, the importance of the correct determination of on the correct calculation of is discussed.

System Noise Suppression of Muzzle Voltage in Augmented Electromagnetic Railgun Based on VMD and the Application in Armature–Rail Contact Characteristics

The muzzle voltage is an important characteristic parameter of electromagnetic railgun. The contact resistance between the sliding armature and the copper rail surface during the launching process can be calculated by utilizing it to analyze the armature–rail contact characteristics. However, in the engineering experiments of augmented electromagnetic railgun, the detected muzzle voltage waveform will be disturbed by the system noise because of the existence of augmented rail, firing sequence of pulse forming network (PFN), and friction of armature–rail contact surface. Therefore, it is difficult to calculate the contact resistance accurately. This article presents a new noise suppression method variational mode decomposition (VMD) for suppressing the jagged noise in the muzzle voltage. A method for calculating the contact resistance is presented to analyze the armature–rail contact characteristics. A frame for analyzing the contact characteristics of the electromagnetic railgun is presented. The method can suppress the system noise by utilizing the signal mode decomposition in the time domain based on the frequency characteristics of VMD. Then, in order to analyze the armature–rail contact characteristics, the contact resistance can be calculated according to the formula derived from the theory. The results show that the method can suppress the muzzle voltage system noise effectively. And the calculated contact resistance wave is smooth, which is helpful to analyze the armature–rail contact characteristics. The noise component extracted from muzzle voltage contains pulse signals, and the time and amplitude of these pulse signals are related to PFN’s firing sequence and the changing trend of the armature–rail contact resistance. The method proposed in this article provides a new and reliable reference for monitoring the launching state of electromagnetic railgun in engineering experiments.

Characterization of a Mass-Produced SiPM at Liquid Nitrogen Temperature for CsI Neutrino Coherent Detectors.

Silicon Photomultiplier (SiPM) is a sensor that can detect low-light signals lower than the single-photon level. In order to study the properties of neutrinos at a low detection threshold and low radioactivity experimental background, a low-temperature CsI neutrino coherent scattering detector is designed to be read by the SiPM sensor. Less thermal noise of SiPM and more light yield of CsI crystals can be obtained at the working temperature of liquid nitrogen. The breakdown voltage (Vbd) and dark count rate (DCR) of SiPM at liquid nitrogen temperature are two key parameters for coherent scattering detection. In this paper, a low-temperature test is conducted on the mass-produced ON Semiconductor J-Series SiPM. We design a cryogenic system for cooling SiPM at liquid nitrogen temperature and the changes of operating voltage and dark noise from room to liquid nitrogen temperature are measured in detail. The results show that SiPM works at the liquid nitrogen temperature, and the dark count rate drops by six orders of magnitude from room temperature (120 kHz/mm2) to liquid nitrogen temperature (0.1 Hz/mm2).

Characterization of programmable integrated quantum voltage noise source with variable power spectral density

Characterization of programmable integrated quantum voltage noise source with variable power spectral density

Design and simulation of reference voltage sources circuit in lasers

AbstractFor the design of reference voltage source circuits in lasers, there is a problem of low accuracy using general design approach, this paper proposes an improved high‐precision voltage source circuit design. Firstly, a suitable reference voltage source chip is selected, then the excitation source circuit with better stability is designed, a high‐order filter is designed for filtering, and finally a compensation circuit is designed to improve the accuracy of the lasers voltage source. The effect of the designed voltage source circuit was verified, and the simulation results showed that the designed voltage source circuit was improved in output voltage accuracy, stability, and noise level, achieving a voltage noise level of 0.978 μV/Hz1/2 at 0.1 mHz at an input voltage of 2V. The validity of the voltage source circuit used for the lasers is verified, providing a high reference value for improving the lasers accuracy in laser spectroscopy.

Ensemble GaAsSb/GaAs axial configured nanowire-based separate absorption, charge, and multiplication avalanche near-infrared photodetectors.

In this study, molecular beam epitaxially grown axially configured ensemble GaAsSb/GaAs separate absorption, charge, and multiplication (SACM) region-based nanowire avalanche photodetector device on non-patterned Si substrate is presented. Our device exhibits a low breakdown voltage (VBR) of ∼ −10 ± 2.5 V under dark, photocurrent gain (M) varying from 20 in linear mode to avalanche gain of 700 at VBR at a 1.064 μm wavelength. Positive temperature dependence of breakdown voltage ∼ 12.6 mV K−1 further affirms avalanche breakdown as the gain mechanism in our SACM NW APDs. Capacitance–voltage (C–V) and temperature-dependent noise characteristics also validated punch-through voltage ascertained from I–V measurements, and avalanche being the dominant gain mechanism in the APDs. The ensemble SACM NW APD device demonstrated a broad spectral room temperature response with a cut-off wavelength of ∼1.2 μm with a responsivity of ∼0.17–0.38 A W−1 at −3 V. This work offers a potential pathway toward realizing tunable nanowire-based avalanche photodetectors compatible with traditional Si technology.

Noise Characterization of Low Noise Voltage Reference at Low Frequency Band

Noise Characterization of Low Noise Voltage Reference at Low Frequency Band

Active inductor based low phase noise voltage controlled oscillator

This paper proposed a fully MOS-based voltage-controlled oscillator (VCO) with tuning range and low phase noise, replacing the most often used NMOS-based inductor-capacitor tank arranged in cross-coupled topology with a high-Q active inductor. This study mainly focuses on VCO design using a MOS-based active inductor and is implemented and verified using UMC 180nm CMOS technology. The proposed VCO is resistorless and consists of an active inductor, two MOS capacitors, and the buffer circuits. The fundamental principle of this MOS-based VCO concept is to use MOS based inductor to replace the passive inductor, which is an active inductor that gives less area and low power usage. At 1 MHz frequency offset, the phase noise achieved by this proposed configuration is -102.78dBc/Hz. In the proposed VCO architecture, the frequency tuning range is 0.5GHz to 1.7GHz. This VCO design can accomplish this acceptable tuning range by altering the regulating voltage from 0.7V to 1.8V. This suggested architecture of proposed VCO design has the power consumption of 9mW with a 1.8V supply voltage. The suggested VCO has been shown to be a good fit for low-power RF circuit applications while preserving acceptable performance metrics.

Assessment of Fuel Cells’ State of Health by Low-Frequency Noise Measurements

We proposed applying low-frequency (flicker) noise in proton-exchange membrane fuel cells under selected loads to assess their state of health. The measurement set-up comprised a precise data acquisition board and was able to record the DC voltage and its random component at the output. The set-up estimated the voltage noise power spectral density at frequencies up to a few hundred mHz. We observed the evolution of the electrical parameters of selected cells of different qualities. We confirmed that flicker noise intensity varied the most (more than 10 times) and preceded changes in the impedance or a drop in the output DC voltage (less than 2 times). The data were observed for current loads (from 0.5 to 32 A) far from the permissible load. We deduce that the method can be utilised in industrial conditions to monitor the state of health of the selected cells by noise analysis. The method can be used in real-time when the flicker noise is measured within the range of a few Hz and requires a reasonable amount of averaging time to estimate its power spectral density. The presented method of flicker noise measurement has considerable potential for use in innovative ways of fuel cell quality monitoring.