Signal Data Acquisition Research Articles

A Practical Study to Enhance Pressure Signal Quality in Mechanical Ventilators Using Moving Average Filtration: A Comparative Study

Undesirable noise and interference present a substantial obstacle in the process of obtaining biomedical signals for analysis and diagnosis. It is necessary to reduce the noise and enhance signal quality for many designs of medical devices such as Mechanical Ventilators (MV), patient monitors and overall biosignal processing. To contribute for addressing this problem, and for medical applications such as MV which are used for critical diseases such as pneumonia, COVID 19 etc. This paper, conducted comparative study to evaluate the performance of a 3-point Moving Average Filter (MAF) and a 5-point MAF in order to reducing noise and improving signal quality in MVs which are used in medical applications. MATLAB was utilized to perform filter approximation, realization and analysis. LabVIEW was employed for pressure signal data acquisition, implementation, and Signal-to-Noise Ratio (SNR) calculation. Experimental data, which needed for filters implementation, were obtained by running a MV connected to an artificial lung and a reference device which is used to measure pressure signal. In general, 3 point presented better SNR against 5 points MAF for pressure signal required in MVs. This approach can potentially enhance healthcare quality by providing better quality of biomedical signals which are used in medical devices.

Measuring the frequency response of an optical microphone system with a fiber based setup

Abstract This paper presents a measurement method for characterizing the frequency response of an optical microphone system using a purely optical approach. The use of optical methods allows to precisely determine the frequency response of the device from infra-sound up to 100 kHz in a single measurement, without the need of a reference microphone. The presented method relies on the inherently flat frequency characteristics of an optical cavity, allowing the assignment of any frequency-dependent behavior to secondary sources, such as the signal conditioning and data acquisition unit. The frequency characteristic was found to be strongly dependent on the settings of the internal amplifiers and high-pass filters, indicating the necessity of a calibration procedure if a flat frequency response is required.

Separation of overlapping non-stationary signals and compressive sensing-based reconstruction using instantaneous frequency estimation

Compressive sensing uses an incomplete sample set to consider signal reconstruction with sparse basis representations over a specific transform domain. This work examines the difficulties encountered in various signal processing applications, such as data overlap with the target signal in time and frequency domains. The conventional filtering and windowing processes fail to promote better results in recovering the desired signal. The non-stationary signal with time-frequency representations is highly significant for certain valuable applications. An efficient signal separation and reconstruction method based on instantaneous frequency estimate is proposed to improve the non-stationary signal outcome. The proposed research includes speech signal data acquisition, signal component decomposition, instantaneous frequency estimation, overlapped signal separation, and reconstruction. Two datasets, Dacon Overlapped Speech and LJ Speech Dataset, are utilized to generate a new overlapped signal dataset. Initially, the generated speech signals are collected and decomposed into several monocomponents using Synchrosqueezing Wavelet Transform (SynWav), Renyi's quadratic entropy (RQuad), Narrow bandpass filtering (NBand) and single frequency filtering (SFreq). The instantaneous frequencies are estimated using the Hilbert-Huang transform (HilHuT) to generate a time-frequency representation of multi-component signals. The overlapped signals are separated and reconstructed to a desired signal using a Compressive sensing-based Discrete Cosine transform with amended intrinsic chirp separation (CDcT_AIChirS). The proposed model is simulated using PYTHON to examine the performances. In comparison, the mean square error is calculated to be 2.71, the root mean square error is calculated to be 1.64, and the signal to noise ratio is calculated to be 32dB.

Design of a multichannel vacuum ultraviolet spectroscopy system for SPARC.

The design of a vacuum ultraviolet spectroscopy system has been performed to monitor and provide feedback for impurity control in SPARC. The spectrometer, covering a wavelength range of 10-2000Å through a flat-field configuration with diffraction gratings, incorporates five survey lines of sight. This allows for comprehensive impurity analysis across the core and four divertor regions (inner/outer and upper/lower). Its compact modular design facilitates vertical stacking of each spectrometer unit, significantly reducing space in the tokamak hall, where a dedicated radiation shielding bunker will be built. Safety features include a secondary helium enclosure to mitigate tritium permeation risks during deuterium-tritium (D-T) operations and shielding within the beamlines for enhanced radiation protection. The silicon carbide mirror design for divertor observation ensures its survivability in the in-vessel environment of SPARC, validated by thermal and electromagnetic analysis. Signal modeling and data acquisition testing results show that an exposure time of a few milliseconds is appropriate considering photon flux reaching the detector, demonstrating the system's capability for discharge control that includes disruption avoidance.

Design and development of the magnetic diagnostic systems for the first operational phase of the SMART tokamak.

A set of magnetic diagnostics has been designed, manufactured, and calibrated for the first operational phase of the small aspect ratio tokamak. The sensor suite comprises of Rogowski coils; 2D magnetic probes; and poloidal, saddle, and diamagnetic flux loops. A set of continuous Rogowski coils has been manufactured for the measurement of plasma current and induced eddy currents in conductive elements. A set of flux loops and magnetic probes will be used as input for the reconstruction of the magnetohydrodynamic equilibrium. The quantity and position of these sensors have been verified to be sufficient with synthetic equilibrium reconstructions using the equilibrium fitting code and baseline scenarios computed with the Fiesta code. These sensors will also be used as input for the real-time control system, and magnetic probes will be used for the detection of plasma instabilities. The calibration procedure for the magnetic probes is described, and the results are shown. The signal conditioning and data acquisition systems are described.

Design of a Real-Time Monitoring System for Electroencephalogram and Electromyography Signals in Cerebral Palsy Rehabilitation via Wearable Devices

Cerebral palsy is a disorder of central motor and postural development, resulting in limited mobility. Cerebral palsy is often accompanied by cognitive impairment and abnormal behavior, significantly impacting individuals and society. Time, energy, and economic investment in the rehabilitation process is substantial, yet the rehabilitation outcomes often remain unsatisfactory. Additionally, some patients have limited sensory perception during rehabilitation training, making it challenging to effectively regulate exercise intensity. Traditional evaluation methods are mostly based on recovery performance, lack guidance at the neurophysiological level, and have an unequal distribution of medical rehabilitation resources, which pose great challenges to the rehabilitation of patients. Based on the issues mentioned above, this paper proposes a real-time cerebral signal monitoring system based on wearable devices. This system can monitor and store blood oxygen, heart rate, myoelectric, and EEG signals during cerebral palsy rehabilitation, and it can track and monitor signals during the rehabilitation treatment process. The system includes two parts: hardware design and software design. The hardware design includes a data signal acquisition module, a main control chip (ESP32), a muscle electrical sensor module, a brain electrical sensor module, a blood/heart rate acquisition module, etc. It is primarily for real-time signal data acquisition, processing, and uploading to the cloud server. The software design includes functions such as data receiving, data processing, data storage, network configuration, and remote communication and enables the visual monitoring of data signals. The system can achieve real-time monitoring of electromyography, electroencephalography, and blood oxygen levels, as well as the heart rate of patients with cerebral palsy, and adjust rehabilitation training in real-time during the rehabilitation process. At the same time, based on the real-time storage of the original electromyography and electroencephalography data, it can provide auxiliary guidance for later rehabilitation evaluation and effective data support for the entire rehabilitation treatment process.

Application of high-sensitivity radon monitor on walk-in type radon calibration chamber at KRISS

This paper introduces the KRISS-Rn4, a high-sensitivity radon monitor with four detection cells, installed within a walk-in type radon calibration chamber at KRISS. The KRISS-Rn4 exhibits enhanced energy resolution through channel-by-channel signal processing and data acquisition. Results reveal that it achieves lower statistical fluctuations and faster response times in monitoring test atmospheres compared to commercial devices.

Real-time signal processing and data acquisition for the Electric Field Detector (EFD-02) on the CSES-02 satellite

The Electric Field Detector (EFD-02) on board the second China Seismo-Electromagnetic Satellite (CSES-02) will measure the electric field components at a Low Earth Orbit (LEO) over a wide frequency band (DC – 3.5 MHz) and with 1 μV/m sensitivity in the Low Frequency band. EFD-02 will measure the voltage differences between pairs of probes installed at the tips of four booms deployed from the satellite. In this article, we describe the Zynq System on Chip (SoC)-based digital hardware subsystem dedicated to signal processing, and the selected implementation strategy, which successfully complied to the specific requirements of the space mission. Furthermore, we present a comprehensive overview of the assessed instrument performance.

FPGA-based CCD signal acquisition and transmission system design

In order to facilitate the analysis and processing of optical signals, an FPGA-based CCD signal acquisition and data transmission system is designed in this work. The system uses an FPGA as the main control device, the TCD1304DG/AP chip as the optical signal detector, and the CYUSB3KIT-003 development board product by Cypress for data transmission. Verilog and Python languages are employed for modular design and on-board verification. Through the coordination of each module, the system successfully achieves CCD signal data acquisition and transmission.

Compton Camera Arrangement With a Monolithic LaBr3(Ce) Scintillator and Pixelated GAGG Detector for Medical Imaging

The results presented in this manuscript are divided in two main parts. The aim of the presented work is to conduct feasibility tests on a Compton camera setup to be later scaled up and used for PET and triple coincidence γ-PET purposes. The first part is focused on laboratory characterization of a monolithic LaBr3(Ce) scintillator coupled to a 64-channel multi-anode photomultiplier (H8500C PMT from Hamamatsu) in combination with a well-established algorithm allowing to determine the interaction’s position resolution. The second part of the article is dedicated to the evaluation of a Compton camera detector arrangement in which the monolithic scintillator acts as an absorber, while a pixelated GAGG scintillator array, read out by a SiPM multi-pixel photon counter (MPPC), is used as a scatterer component. The accuracy achievable with this system for detecting γ rays from laboratory point sources is investigated. The Compton camera system has been tested with radioactive 137Cs and 60Co point sources. The signal readout and data acquisition system is based on individual spectroscopy electronics modules (NIM and VME), for the absorber and a customized electronics based on Anger logic for the GAGG scatter array. The raw data were analyzed to serve as input for the image reconstruction, performed using the MEGAlib toolkit software. With a spatial resolution of 1 mm for the scatterer and less than 3 mm for the absorber component, respectively, shifts of 2 mm of both radioactive sources (137Cs and 60Co) could be resolved with the whole Compton camera system.

Experimental Study on Axial Stress and Hammer Impacting Energy of Offshore Standard Penetration Test

Standard penetration test (SPT) has been widely used in offshore exploration because of its unique advantages. Unlike onshore exploration, offshore construction areas are characterized by high waves and water depths ranging from several meters to tens of meters. As a result, the reliability of offshore SPT is significantly reduced compared with onshore SPT. Currently, the probe rod length correction of SPT is not involved in geotechnical engineering investigation codes and related research, which greatly limits the application of this method in offshore exploration. Therefore, a series of SPTs were carried out in offshore environments with different water depths, with a maximum rod length of 65 m. The acceleration and axial stress at each test point of the rod were monitored by the dynamic signal data acquisition system, and the hammer impacting energy at each test point was obtained by Force–Velocity (F-V) method. The test results show that the correction of the rod length of the offshore SPT is different from that of the traditional SPT, and it needs to be further corrected for the water depth. In this paper, a modified method of rod length for offshore SPT is proposed, which can provide reference for the application of offshore SPT.

A Multichannel Portable Platform With Embedded Thermal Management for Miniaturized Dielectric Blood Coagulometry.

This article presents a standalone, multichannel, miniaturized impedance analyzer (MIA) system for dielectric blood coagulometry measurements with a microfluidic sensor termed ClotChip. The system incorporates a front-end interface board for 4-channel impedance measurements at an excitation frequency of 1 MHz, an integrated resistive heater formed by a pair of printed-circuit board (PCB) traces to keep the blood sample near a physiologic temperature of 37 °C, a software-defined instrument module for signal generation and data acquisition, and a Raspberry Pi-based embedded computer with 7-inch touchscreen display for signal processing and user interface. When measuring fixed test impedances across all four channels, the MIA system exhibits an excellent agreement with a benchtop impedance analyzer, with rms errors of ≤0.30% over a capacitance range of 47-330 pF and ≤0.35% over a conductance range of 2.13-10 mS. Using in vitro-modified human whole blood samples, the two ClotChip output parameters, namely, the time to reach a permittivity peak (Tpeak) and maximum change in permittivity after the peak (Δϵr,max) are assessed by the MIA system and benchmarked against the corresponding parameters of a rotational thromboelastometry (ROTEM) assay. Tpeak exhibits a very strong positive correlation (r = 0.98, p < 10-6, n = 20) with the ROTEM clotting time (CT) parameter, while Δϵr,max exhibits a very strong positive correlation (r = 0.92, p < 10-6, n = 20) with the ROTEM maximum clot firmness (MCF) parameter. This work shows the potential of the MIA system as a standalone, multichannel, portable platform for comprehensive assessment of hemostasis at the point-of-care/point-of-injury (POC/POI).

Ocean-Surface Wave Measurements Using Scintillation Theories on Seaborne Software-Defined GPS and SBAS Reflectometry Observations.

In this study, a low-cost, software-defined Global Positioning System (GPS) and Satellite-Based Augmentation System (SBAS) Reflectometry (GPS&SBAS-R) system has been built and proposed to measure ocean-surface wave parameters on board the research vessel New Ocean Researcher 1 (R/V NOR-1) of Taiwan. A power-law, ocean-wave spectrum model has been used and applied with the Small Perturbation Method approach to solve the electromagnetic wave scattering problem from rough ocean surface, and compared with experimental seaborne GPS&SBAS-R observations. Meanwhile, the intensity scintillations of high-sampling GPS&SBAS-R signal acquisition data are thought to be caused by the moving of rough surfaces of the targeted ocean. We found that each derived scintillation power spectrum is a Fresnel-filtering result on ocean-surface elevation fluctuations and depends on the First Fresnel Zone (FFZ) distance and the ocean-surface wave velocity. The determined ocean-surface wave speeds have been compared and validated against nearby buoy measurements.

Charge Couple Device (CCD) Photoelectric Signal Data Acquisition and Its Application in the Machine Vision of Artificial Intelligence

The development of Charge Couple Device (CCD) technology is particularly rapid in the fields of image sensors and non-contact measurement. In this study, a data acquisition device applied to CCD photoelectric detection system is designed. Among them, the design of the Differential Amplification (DA) module, Analog-to-Digital Converter (ADC) module, First In First Out (FIFO) cache module, and Complex Programmable Logic Device (CPLD) module in this device are emphasized. The ADC circuit in the ADC module converts two 4 MHz analog photoelectric signals generated by the CCD sensor at a frequency of 8 MHz, and then outputs 12-bit digital signals. The collected photoelectric signal is used to detect the damage to the surface of ancient buildings with the machine vision technology of artificial intelligence (AI). In the test, the DA circuit can adjust the voltage range of two photoelectric analog signals output by CCD to a predetermined range (1.5 V∼2.0 V). In the ADC circuit test, there is no data in the FIFO when there is no input conversion, and the converted data will be stored in the internal FIFO during the conversion clock period. Based on machine vision technology, surface damage types of ancient buildings are defined, namely spalling, cracks, and disruption, and surface image samples are generated from collected signals. The samples are trained using the convolutional neural network, and the classifier is generated. The test reveals that the designed photoelectric signal acquisition device and AI machine vision technology can accurately classify the surface damage of ancient buildings.

Arduino-Based High-Frequency Signal Data Acquisition for Learning Media on Antenna and Wave Propagation Practices

This paper discusses the research results on the development of learning media and the results of the feasibility test for the learning process. This study aims to: (1) obtain the design and prototype of Arduino-based high-frequency signal data acquisition learning media; (2) find out the level of feasibility of learning media that has been made for the learning process of Antenna Practice and Wave Propagation courses. The research model uses Research and Development with the ADDIE development method. The research stages in the ADDIE method are Analyze, Design, Develop, Implement, and Evaluate. The research began with the development of learning media called Antenna Pattern Radiation Learning Media and the Practicum Module containing a collection of lab sheets for practicum activities using the media. The next step involves assessing the viability of the media. Validation tests gather expert feedback on materials, media, and users. In this study, data was collected using a questionnaire and analyzed quantitatively using descriptive analysis techniques. This research and development effort led to the creation of Antenna Pattern Radiation Learning Media and its practical modules. The test results showed that the material experts gave it a score of 95%, media experts rated it at 85.4%, and users (students) gave it a score of 80.65%. Based on the evaluations of the material experts, media experts, and users, it can be concluded that the Antenna Pattern Radiation learning media falls into the highly feasible category and can be utilized as a learning resource in courses related to Antenna and Wave Propagation.

Small Size and Low‐Cost TENG‐Based Self‐Powered Vibration Measuring and Alerting System

AbstractVibration measurement systems containing sensors, signal conditioning, and data acquisition devices, are important for monitoring motors, gearboxes, turbines, etc. Microelectromechanical and piezoelectric sensors are predominantly used for vibration measurements. However, they are not cost‐effective, flexible in design, and incapable of self‐powering. Recently, triboelectric nano‐generator (TENG)‐based vibration sensors have been considered as a possible alternative to resolve this problem, and tremendous progress has been achieved. Previous work on TENG‐based sensors is limited to optimizing the sensor design, while the signal conditioning and data acquisition of TENG signal still need investigation for actual applications. This work develops a TENG‐based vibration measurement device and self‐powered alerting system that is integrated with the signal condition and data acquisition systems. The experimental results show that the proposed measurement system successfully measures signals within the range of 0–1800 Hz frequency. Meanwhile, the TENG generates a high output, up to 80 V and 0.55 µA from small size TENG area (3.6 cm2). The signal is adequate to harvest energy for self‐powering to drive alerting components (harvest 320 mJ in 36 h, which drives alarming for duration of 1.5 s). The proposed device is cost‐effective (30 $), small (105 cm3), and consumes less power (0.18 W) in comparison to commercial devices.

Hypo- and hyper-perfusion in MCI and AD identified by different ASL MRI sequences.

Arterial spin labeling (ASL) perfusion MRI has been increasingly used in Alzheimer's Disease (AD) research. However, ASL MRI sequences differ greatly in terms of arterial blood signal preparations and data acquisition strategies, both leading to a large difference of signal-to-noise ratio (SNR). It is of great translational importance to compare the several widely used ASL MRI sequences regarding sensitivity of ASL measured cerebral blood flow (CBF) for detecting the between-group difference across the AD continuum. To this end, this study compared three ASL MRI sequences in AD research, including the 2D Pulsed ASL (PASL), 3D Background Suppressed (BS) PASL, and 3D BS Pseudo-Continuous ASL (PCASL). We used data from 100 healthy and cognitively normal elderly control (NC) subjects, 75 patients with mild cognitive impairment (MCI), and 57 Alzheimer's disease (AD) subjects from the AD neuroimaging initiative (ADNI). Both cross-sectional perfusion difference and perfusion versus clinical assessment correlations were examined. The major findings included: 3D PCASL sequence identified stronger patient versus control CBF/rCBF differences than 2D PASL and 3D PASL; MCI showed reduced CBF and CBF redistribution; CBF in orbito-frontal cortex presents a new U-shape change pattern from normal aging to MCI and to AD; 3D PCASL identified a negative rCBF to memory correlation while 2D PASL showed a positive correlation.

Nanostructured (Ti,Cu)N Dry Electrodes for Advanced Control of the Neuromuscular Activity

This research reports a novel concept of dry surface electrodes designed to act in a dual-role biofeedback process: monitoring and stimulating the muscle’s electrical activity. A new strategy based on 3-D printed polymeric disk-shaped substrates functionalized with nanostructured (Ti,Cu)N thin films to be integrated into rehabilitation wearables. Five different chemical compositions with different microstructural features were grown by dc magnetron sputtering on polyurethane (PU), polylactide, and cellulose polymers and tested as electrodes. In the first phase, the electromyography (EMG) activity for both resting and muscle contraction of the bicep muscle was assessed using the LabVIEW software coupled to a NI 9234 signal data acquisition system and processed with MATLAB algorithms. The second phase tested the maximum electrical stimulation capable of being delivered without crosstalking between stimulation and sensing processes, using a TENS 7000 commercial unit. The tests highlighted the potential of the flexible PU bases among their counterparts, whereas the dense and soft electrodes of titanium doped with 25.6.% of copper were able to stimulate at a 100-mA full current output without discomfort for the subject exhibiting simultaneously the lowest EMG detection limit. The research conducted enhances the strong potential of using dry electrodes in new technologies and strategies capable of delivering primary and integrated care adapted to foster functional abilities.

Studies and optimization of scintillation light measurements for the development of the 3-gamma medical imaging XEMIS2 liquid xenon Compton camera

We report the studies and optimization of scintillation light measurements in an updated version of the XEMIS1 prototype for the development of the XEMIS2 camera. A novel monolithic liquid xenon Compton camera, named XEMIS2 (XEnon Medical Imaging System), attempts to achieve low-activity small-animal imaging using the 3-gamma imaging technique. This emerging detector relies on the time projection chamber technique: it will be able to perform a simultaneous detection of the three γ -rays emitted by a specific radionuclide, such as scandium-44, and to produce a good quality image with a remarkable diminution of radiopharmaceutical activity at the same time. Vacuum Ultraviolet (VUV) scintillation light and ionization charge carriers generated from the recoiling particles within the detector are detected and used to reconstruct the interaction position and deposited energy. A cost-effective self-triggering scintillation signal read-out and data acquisition (DAQ) system has been developed to achieve a continuous data read-out with negligible electronics dead time. The DAQ prototype has been installed and qualified in an updated version of the XEMIS1 detector. It reaches the performance specifications in scintillation light measurements. Moreover, scintillation signals can also be used for the virtual segmentation of the monolithic detection volume through the matching algorithm of the scintillation and ionization signals based on the light collection map (LCM). This spatial pre-localization of the physical events, called the virtual fiducialization of the active volume, is used to lower the detector occupancy rate when the administered activity is increased to lessen the examination time. The XEMIS1 experimental LCMs indicate that each PMT owns an individual field of view so as to segment the active volume virtually. The preparation work for the XEMIS2 camera operation has been completed in the updated XEMIS1 detector while the XEMIS2 scintillation light measurement system is under commissioning in Nantes Centre Hospitalier Universitaire. • The XEMIS2 camera oriented to the whole-body small animal 3-gamma medical imaging is presented. • The XEMIS2 system is a monolithic liquid xenon Compton camera with a 24 cm axial field of view. • A dedicated cost-effective 16-channel self-triggering scintillation signal front-end read-out electronics called XSRETOT is described. • The experimental light collection maps of an updated version of the XEMIS1 detector have been built, which can be used for the virtual segmentation of the monolithic detection volume to reduce the detector occupancy rate in the context of increasing the administered activity.

Evaluation of experience from long-term ae monitoring

A working group within the Committee on Acoustic Emission Testing of the German Society for Nondestructive Testing (FA-SEP of DGZfP) has collected published data on the long-term behavior of the AE or the Guided Ultrasonic Wave (GUW) measurement chain (sensor, sensor coupling and mounting, signal transmission, data acquisition and storage). Since only scant data is publicly available, the working group drafted a questionnaire for collecting respective information from the committee members. The returned questionnaires indicate that data acquisition and storage likely pose problems more frequently than other parts of the measurement chain. The only exception noted was for one case of integrity monitoring at elevated temperatures. In this case, sensor sensitivity was observed to decrease compared to the performance at room temperature, requiring the mounting of additional sensors for achieving AE source location with the same resolution. Based on the empirical information, recommendations for long-term monitoring with AE and GUW are discussed. These comprise, e.g., periodic checks of sensors and measurement chain, periodic data back-up, and planning of maintenance and repair.