Signal Conditioning Research Articles

Variable gain DNA nanostructure charge amplifiers for biosensing.

Electronic measurements of engineered nanostructures comprised solely of DNA (DNA origami) enable new signal conditioning modalities for use in biosensing. DNA origami, designed to take on arbitrary shapes and allow programmable motion triggered by conjugated biomolecules, have sufficient mass and charge to generate a large electrochemical signal. Here, we demonstrate the ability to electrostatically control the DNA origami conformation, and thereby the resulting signal amplification, when the structure binds a nucleic acid analyte. Critically, unlike previous studies that employ DNA origami to amplify an electrical signal, we show that the conformation changes under an applied field are reversible. This applied field also simultaneously accelerates structural transitions above the rate determined by thermal motion. We tuned this property of the structures to achieve a response that was ≈2 × 104 times greater (i.e., a gain or amplification) than the value from DNA hybridization under similar conditions. Because this signal amplification is independent of DNA origami-analyte interactions, our approach is agnostic of the end application. Furthermore, since large signal changes are only triggered in response to desirable interactions, we minimize the deleterious effects of non-specific binding. The above benefits of self-assembled DNA origami make them ideally suited for multiplexed biosensing when paired with highly parallel electronic readout.

Markov Modeling of Signal Condition Transitions for Bearing Diagnostics Under External Interference Conditions

Markov Modeling of Signal Condition Transitions for Bearing Diagnostics Under External Interference Conditions

A Fingertip-Mimicking 12×16 200μm-Resolution e-skin Taxel Readout Chip with per-Taxel Spiking Readout and Embedded Receptive Field Processing.

This paper presents an electronic skin (e-skin) taxel array readout chip in 0.18μm CMOS technology, achieving the highest reported spatial resolution of 200μm, comparable to human fingertips. A key innovation is the integration on chip of a 12×16 polyvinylidene fluoride (PVDF)-based piezoelectric sensor array with per-taxel signal conditioning frontend and spiking readout combined with local embedded neuromorphic first-order processing through Complex Receptive Fields (CRFs). Experimental results show that Spiking Neural Network (SNN)-based classification of the chip's spatiotemporal spiking output for input tactile stimuli such as texture and flutter frequency achieves excellent accuracies up to 97.1% and 99.2%, respectively. SNN-based classification of the indentation period applied to the on-chip PVDF sensors achieved 95.5% classification accuracy, despite using only a small 256-neuron SNN classifier, a low equivalent spike encoding resolution of 3-5 bits, and a sub-Nyquist 2.2kevent/s population spiking rate, a state-of-the-art power consumption of 12.33nW per-taxel, and 75μW-5mW for the entire chip is obtained. Finally, a comparison of the texture classification accuracies between two on-chip spike encoder outputs shows that the proposed neuromorphic level-crossing sampling (NLCS) architecture with a decaying threshold outperforms the conventional bipolar level-crossing sampling (LCS) architecture with fixed threshold.

Low Noise Operational Amplifier using Current Driving Bulk by CMOS Technology

A reverse substrate bias operational amplifier using existing driver technology has been designed and implemented using 0.25μm CMOS process to achieve high noise performance. Op amps are efficient and versatile devices. Its applications include signal conditioning, custom conversion, analog equipment, competitive simulation, and various electronic industries meeting custom design requirements. As the trend of low voltage devices continues, designing high-performance analog circuits becomes increasingly difficult. The main module of analog circuits is the work amplifier. In large electronic devices, there is a trade-off between speed, power, and gain, among other drawbacks. Additionally, in order to reduce costs and integrate analog and digital circuits on a single die, analog designers must face the challenges of using the CMOS process. Design and implementation are done in 0.25μm technology using TSMC libraries and with the help of Tanner tools.

Designing tools for assessing the reliability of electric motor torque measurements by using identifiers of anomalous deviations in a noisy signal system

The problem of the reliability of measurements of rotational parameters of electric motors was solved, which was focused on the development of an algorithm for evaluating measurements under conditions of additional noise. An analysis of methodological approaches and mathematical tools used to process and interpret the uncertainty of measurement results was carried out. Cases where they may not be effective due to high noise levels were considered. To detect anomalies in the signal, an algorithm for assessing the reliability of measurements using fuzzy logic was proposed. A structural diagram of the model for measuring the torque of an electric motor under the conditions of a noisy signal was developed, where transfer functions were used to model the angular velocity and torque parameters. A method for detecting anomalies in noisy signals is presented, which identifies the amplitude and time characteristics of spiking pulses. The method includes the application of a wide range of analytical tools for deep analysis of signals and is particularly effective for detecting anomalies that may be hidden in background noise. A prototype of a measuring bench was developed, which uses neural networks to detect anomalies when measuring the rotational parameters of electric motors, which made it possible to obtain a training sample using a sample electric motor and apply it to evaluate the parameters of another electric motor. In a practical aspect, the developed methods and technological solutions for improving the reliability of measurements of rotational parameters of electric motors could be used to make corrections in existing systems. In particular, they could be used in industry, electric transport, as well as in the aerospace and military sectors where the reliability of measuring systems is important

Design of a Novel Magnetic Induction Switch with a Permalloy Film and a Trans-Impedance Amplifier Circuit

At present, magnetic induction switches are widely used in industrial automation control and biological sensing systems. A core module composed of a magnetic sensing device and a signal conditioning circuit is designed and analyzed in this paper. Utilizing a permalloy film with the anisotropic magneto-resistance (AMR) effect, the novel magnetic induction switch shows its ability to correctly detect the direction of magnetic fields. Furthermore, an interfacial circuit based on a trans-impedance amplifier (TIA) is designed to measure and regulate the output signal of the sensing device. Accurate simulation results show the gain of the TIA reaches up to 51.36 dB with a bandwidth of 1.3 GHz and a power consumption of 3.65 mW. The outstanding performance of the proposed module demonstrates the possibility of solving the problems induced by high input impedance, high frequency, and parasitic effects in magnetic induction switches.

The Design of a Location Monitoring System for a Fleet of Electric Scooters

The development of geolocation systems( geostationary satellite networks), as well as devices capable of receiving signals and processing the data coming from them, makes possible the implementation of location monitoring systems for various purposes. Whether it's about security or optimizing travel times or routes, these systems are based on information in the form of global coordinates (latitude and longitude) from satellite systems or cell towers. The design of such a system is presented in this paper, being a good guide in the design and implementation of such a system, regardless of the application. Both, the hardware part (the designed equipment) and the software part (the backend component running on a virtual private server, as well as a mobile application) are presented in this paper. In the development of the system, was used only location provided by information from satellites, without using GSM cell signals. The entire system has been successfully tested in different GSM signal conditions as well as various locations to see the influence of environmental parameters on performance. The system described in the paper can be the starting point for the development of other systems for a variety of applications that require the management of the location of some devices.

Development of a low-cost, compact, wireless, 16 - channel biopotential data acquisition, signal conditioning and arbitrary waveform stimulator.

The health and fitness of the human body rely heavily on physiological parameters. These parameters can be measured using various tools such as ECG, EMG, EEG, EOG, among others, to obtain real-time physiological data. Analysing the bio-signals obtained from these measurements can provide valuable information that can be used to improve health-care in terms of observation, diagnosis, and treatment. In bio-signal pattern recognition applications, more channels provide multiple information simultaneously. Different biosignal acquisition devices are available in the market, most of which are designed for specific signals like ECG, EMG, EEG etc The gain of the amplifiers and frequency of the filters are designed as per the targeted signals; due to which one device cannot be used for other signals. Also, most of the systems are wired system which is not comfortable for animal studies. In this paper, a low-cost, compact, wireless, 16 channel biopotential data acquisition system with integrated electrical stimulator is designed and implemented. There are several novel and flexible design approaches were incorporated in the proposed design like (1) It has user selectable digital filter in each channel based on the signal frequencies like ECG, EMG, EEG, EOG. The same system will be used to acquire different signals simultaneously. (2) It has variable gain with a configurable analog bandpass filter. (3) It can acquire signals from 4 patients simultaneously. (4) The system is capable to acquire signal from both two-electrode as well as three-electrode configurations. (5) It has integrated stimulator with trapezoidal, charge-balanced, biphasic stimulus output with near zero DC level and user selectable pulse duration or frequency of the stimulus. The developed system has the ability to acquire and transmit data wirelessly in real-time at a high transfer rate. To validate the performance of the system, tests were conducted on the acquired signals using a simulator.

Design of Voltage Transducer for Digital Signal Processing Development Kit in Implementation of a High Step-up DC-DC Converter

High step-up DC-DC converters are used in many industrial applications Especially, renewable energy systems that have a low output voltage and high output current need DC-DC converters with high voltage gain to meet the requirements of the grid-connected systems for a high output voltage. This study is aimed to design an implementation of hardware of the high step-up DC-DC converter’s measurement board prototype for digital signal processing (DSP) TMS320F28335 development kits. The vital parameter to detect for high step-up application systems is a sampling output voltage. This sample of output voltage is produced by using the voltage transducer (LV 25-P) with hall effect sensor in this research. A signal conditioning circuit includes an operational amplifier featuring unity gain buffer for the protection ADC of the DSP and a low pass filter circuit. Therefore, the requirements of the ADC of EZDSP TMS320F28335 development kit can be met by using this voltage transducer sensor and the signal conditioning circuit.

Tight GNSS/INS integration

GNSS/INS tight integration algorithm has been studied in this paper. The main idea is to get the user’s position by considering the solution of a restricted version of the GNSS optimization problem, in which the classical tripartite is limited to INS measurements. It leads to a linearly bounded least squares problem, which may be solved in the worst case in polynomial time. The efficiency of the algorithm is confirmed by simulations in complex scenarios (multipath and weak signal conditions) and shows improved performance compared to autonomous GNSS AND GNSS/INS Kalman in the same conditions.

Experimental comparison of operational amplifier and voltage sensor-based zero-crossing detector circuits for power electronic converters

Abstract Zero-crossing detection (ZCD) circuits are widely utilized to synchronize power electronics converters with the grid and measure frequency and phase angle. They are usually designed using an operational amplifier (op-amp) or a voltage sensor accompanied by a processing device. The performance profile of these circuits alters depending on many factors, including the input voltage level. An experimental comparison between the two ZCD circuits across various input voltage levels does not appear to be presented in the literature. This work experimentally compares the performance of an op-amp and an isolated voltage sensor-based ZCD circuits, considering their rise/fall latency and precision in detecting the zero-crossing points (ZCPs). The design process and the experimental results demonstrated that the op-amp-based ZCD circuit is susceptible to false and multiple detections of ZCPs and is best suited for relatively low-voltage applications. On the other hand, the voltage sensor-based ZCD circuit allows signal conditioning and is best suited for relatively high voltage applications.

Testing a computational model for aural detection of aircraft in ambient noise.

Computational models are used to predict the performance of human listeners for carefully specified signal and noise conditions. However, there may be substantial discrepancies between the conditions under which listeners are tested and those used for model predictions. Thus, models may predict better performance than exhibited by the listeners, or they may "fail" to capture the ability of the listener to respond to subtle stimulus conditions. This study tested a computational model devised to predict a listener's ability to detect an aircraft in various soundscapes. The model and listeners processed the same sound recordings under carefully specified testing conditions. Details of signal and masker calibration were carefully matched, and the model was tested using the same adaptive tracking paradigm. Perhaps most importantly, the behavioral results were not available to the modeler before the model predictions were presented. Recordings from three different aircraft were used as the target signals. Maskers were derived from recordings obtained at nine locations ranging from very quiet rural environments to suburban and urban settings. Overall, with a few exceptions, model predictions matched the performance of the listeners very well. Discussion focuses on those differences and possible reasons for their occurrence.

Compact RF transmission unit for nuclear quadrupole resonance spectroscopy

Nuclear quadrupole resonance (NQR) spectroscopy is a non-destructive measurement technique that enables to detect materials of interest very accurately. This technique works by sending high power electromagnetic waves with radio frequency (RF) very specific to the molecular structure to excite the sample and detecting the respond signal with the same frequency. Portable NQR detectors can be potentially developed to detect explosives with non-metallic containers in the fields. However, commercial RF high power amplifiers are large and heavy, so they are not practical for field usage. In this work, we demonstrate a compact NQR transmission part which composed of an active input signal conditioner, a class-D amplifier, and an NQR coil. The active input signal conditioner circuit will convert a single rf pulse with low amplitude (<0.5Vp) to two pulses (with 180° phase difference) and they are subsequently amplified to TTL level. In the class-D amplifier, the pre-amplified pulses are further amplified by a high voltage gate driver IC to 24V amplitude. These high voltage pulses are converted to a single 24V pulse by MOSFETs connected in a half bridge configuration. Finally, the amplified pulse is fed to the NQR coil, i.e., a low impedance LC series resonance circuit. The voltage across the coil at resonance frequency is about 1kVpp.

Power Quality Improvement and Signal Conditioning of PV Array and Grid Interfaced Off-Board Charger for Electric Vehicles with V2G and G2V Capabilities

Power Quality Improvement and Signal Conditioning of PV Array and Grid Interfaced Off-Board Charger for Electric Vehicles with V2G and G2V Capabilities

Research on Low Noise Chopping Amplifier Circuit Based on Feedback Regulation

In order to overcome the limitation of 1/f noise on long-period magnetotelluric sensors, it is necessary to use low-noise chopping technology for signal conditioning. However, the static operating point drift of Junction Field-Effect Transistor (JFET) is difficult to achieve stable amplification with the chopper technology. This paper proposes a low noise amplifier (LNA) with chopper technology based on feedback adjustment. The LNA reduces the turning frequency of the circuit, and maintains the JFET static point. At 375mHz, its noise is 2.55nV/Hz .

Glass Devices for Next-Generation Packaging and RF Signal Conditioning

The push for higher communications frequencies, greater system integration, and smaller space imparts many unique challenges on RF and packaging engineers in the development of next generation cellular products for 5G, WiFi 6, Military, and other applications. Traditional materials, such as LTCC, organic laminates, and silicon face major limitations to dramatically improve system size, weight, and performance (SWAP). Photosensitive Glass-Ceramics (PSG) have gained a lot of attention as a next generation RF and RF packaging substrate for their ability to simultaneously solve these two important challenges. In this paper the authors will present on our work using PSG for RF and RF packaging solutions. We will share (1) the advantages of using PSG for advanced RF packages, and (2) our work demonstrating glass as an RF substrate integrating discrete components and embedded die for passive RF filters, and (3) our work towards building vertically stacked glass packages for advanced RF systems-in-package (SiP). The described work presents a manufacturing platform for the production of vertically stacked glass substrates with integrated high Quality Factor passive devices, such as inductors and capacitors, and heterogeneously integrated surface mount devices for advanced RF systems-in-package. The presented material demonstrates a production and assembly process for the manufacturing of advanced systems. In this paper, we present design, production, assembly considerations that impact size, weight, and performance (SWAP) metrics for a variety of product definitions and multiple simulation vs. product testing to demonstrate a reliable design to product flow.

Primacy of mouth over eyes to perceive audiovisual Mandarin lexical tones.

The visual cues of lexical tones are more implicit and much less investigated than consonants and vowels, and it is still unclear what facial areas contribute to facial tones identification. This study investigated Chinese and English speakers' eye movements when they were asked to identify audiovisual Mandarin lexical tones. The Chinese and English speakers were presented with an audiovisual clip of Mandarin monosyllables (for instance, /ă/, /à/, /ĭ/, /ì/) and were asked to identify whether the syllables were a dipping tone (/ă/, / ĭ/) or a falling tone (/ à/, /ì/). These audiovisual syllables were presented in clear, noisy and silent (absence of audio signal) conditions. An eye-tracker recorded the participants' eye movements. Results showed that the participants gazed more at the mouth than the eyes. In addition, when acoustic conditions became adverse, both the Chinese and English speakers increased their gaze duration at the mouth rather than at the eyes. The findings suggested that the mouth is the primary area that listeners utilise in their perception of audiovisual lexical tones. The similar eye movements between the Chinese and English speakers imply that the mouth acts as a perceptual cue that provides articulatory information, as opposed to social and pragmatic information.

Evaluation of haematological, genotoxic, cytotoxic and ATR-FTIR alterations in blood cells of fish Channa punctatus after acute exposure of aniline

Aniline (C6H5NH2) an important intermediate in the organic and fine chemical industry, is ubiquitously used worldwide. It is one of the important building block for manufacturing of 4,4-methylene diphenyl diisocyanate (MDI), accelerators in rubber processing, dyes, tattoo inks, photographic chemicals, antioxidants, corrosion inhibitors, pharmaceuticals and antiseptics. The current study evaluated 96 h LC50 of aniline and based on this, two sublethal concentrations (4.19 mg/l and 8.39 mg/l) were selected for acute exposure studies in freshwater food fish Channa punctatus. Erythrocytes of fish are nucleated hence they play an important role in physiology, immune system, protein signalling and haemostatic condition along with respiration. Blood samples were collected after 24, 48, 72, and 96 h of exposure to study haematological, cytotoxic and genotoxic effects of sublethal concentrations of aniline in C. punctatus. Symbolic elevation in time and dose dependent DNA damage was observed by comet assay as well as micronuclei assay revealing maximum damage after 96 h of exposure. After aniline exposure, scanning electron microscopy and ATR-FTIR studies showed anomalies in structure and alterations in biomolecules of RBCs of aniline exposed group as compared to control group respectively. Semi prep HPLC studies revealed bioaccumulation potential of aniline in higher concentration exposed group.

The synchronous detection technique for the accurate monitoring of high-energy pulsed X-rays

At high energy, the smaller inelastic nucleon-Carbon cross-section implies that diamond has a radiation hardness an order of magnitude higher than that of silicon. The production of high-quality diamond crystals and films grown using the chemical vapor deposition technique opened the way for the use of synthetic diamonds in the fabrication of detectors for charged particles and high-energy photons. More recently, laser-processing technology for the fabrication of three-dimensional contacts in diamond has been proposed to produce highly efficient detectors, even with ultra-low active volumes. However, buried-contact structures made with laser treatments unavoidably induce structural defects in the volume surrounding the buried columns, thus affecting the detector response due to trap-related charge transport mechanisms. When pulsed radiation is concerned, experimental results reported in this work demonstrate that synchronous signal conditioning can strongly mitigate the trap-mediated contribution, thereby improving the performance of the overall detection system. Significantly, these results pave the way for the application of diamond samples with three-dimensional buried-contacts in the development of detectors for accurate dosimetry.

AM/AM and AM/PM Characterization of a GaN Phase and Amplitude Setting Circuit

This contribution presents the AM/AM and AM/PM characteristics of a 6-bit Phase and Amplitude Setting Circuit realized in Gallium Nitride technology and operating at the Ku band. A test bench, based on three vector receivers and an absolute power reference, has been purposely devised to capture the deviation with respect to the linear behavior (known by the S-parameters) for both the magnitude and the phase of the vector response. The complete 64-state constellation is reported up to a 37 dBm of input power level, at which the effects of the static AM/AM and AM/PM distortion become evident, with about 3 dB of gain compression and 2.7 deg of phase conversion. The key figure of merit of the proposed test bench is the capability of operating with very high driving power levels (potentially up to 41 dBm), with possible applications in phased arrays, AESAs, and other signal conditioning systems.