Low-noise Method Research Articles

Novel near E-Field Topography Sensor for Human-Machine Interfacing in Robotic Applications.

This work investigates a new sensing technology for use in robotic human-machine interface (HMI) applications. The proposed method uses near E-field sensing to measure small changes in the limb surface topography due to muscle actuation over time. The sensors introduced in this work provide a non-contact, low-computational-cost, and low-noise method for sensing muscle activity. By evaluating the key sensor characteristics, such as accuracy, hysteresis, and resolution, the performance of this sensor is validated. Then, to understand the potential performance in intention detection, the unmodified digital output of the sensor is analysed against movements of the hand and fingers. This is done to demonstrate the worst-case scenario and to show that the sensor provides highly targeted and relevant data on muscle activation before any further processing. Finally, a convolutional neural network is used to perform joint angle prediction over nine degrees of freedom, achieving high-level regression performance with an RMSE value of less than six degrees for thumb and wrist movements and 11 degrees for finger movements. This work demonstrates the promising performance of this novel approach to sensing for use in human-machine interfaces.

Feasibility of noise-reduction reconstruction technology based on non-local-mean principle in SiPM-PET/CT

Quantitative values of positron emission tomography (PET) images using non-local-mean in a silicon photomultiplier (SiPM)-PET/computed tomography (CT) system with phantom and clinical images.The evaluation was conducted on a National Electrical Manufacturers Association body phantom with micro-spheres (4, 5, 6, 8, 10, 13 mm) and clinical images using the SiPM-PET/CT system.The signal-to-background ratio of the phantom was set to 4, and all PET image data was obtained and reconstructed using three-dimensional ordered subset expectation maximization, time-of-flight, point-spread function, and a 4-mm Gaussian filter (GF) and clear adaptive low-noise method (CaLM) in mild, standard, and strong intensities.The evaluation included the standardized uptake value (SUV), percent contrast (QH), coefficient of variation of the background area (CVbackground) clinical imaging for SUV of lung nodules, liver signal-to-noise ratio (SNR), and visual evaluation.SUVmax for 8-mm sphere in phantom images at 2 min for GF and CaLM (mild, standard, strong) were 2.11, 2.32, 2.02, and 1.72; the QH, 8 mm was 27.33 %, 27.47 %, 21.81 %, and 16.09 %; and CVbackground was 12.78, 11.35, 7.86, and 4.71, respectively.CaLM demonstrated higher SUVmax in clinical images than GF for all lung nodule sizes. The average SUVmax for nodules with a diameter of ≤ 1 cm were 5.9 ± 2.4, 9.9 ± 4.9, 9.9 ± 5.0, and 9.9 ± 5.0 for GF and CaLM-mild, standard, and strong intensities, respectively.Liver SNRs were higher for CaLM (mild, standard, strong) compared to GF, with increasing CaLM intensity causing higher liver SNR. CaLM-mild and standard demonstrated suitability for diagnosis in visual evaluation.

An improved PVT-Robust floating inverter dynamic amplifier for noise-shaping SAR ADCs

The floating inverter dynamic amplifier (FIDA) is a power-efficient, open-loop, and dynamic amplifier without requiring any output common-mode feedback (CMFB) circuit. It is appropriate for low-power applications. However, its gain is not robust over process, voltage, and temperature (PVT) variations. In this work, a simple, low power, and low noise method is proposed to solve this problem. The proposed method controls the amplification time window of the FIDA to be proportional to its time constant. Based on the FIDA gain formula, this technique stabilizes the gain over PVT changes. The proposed PVT-robust FIDA is designed at the circuit level using 0.18 µm TSMC CMOS technology with Cadence Virtuoso tool. According to the post-layout simulation results of a sample design, the gain of the amplifier is 29.4 with 51.3 µW power consumption from a 1.2 V supply voltage. The maximum gain variation over PVT changes is reduced from 49.6% to 9.8% using the proposed gain calibration technique.

Effective low-noise technologies for the production of pile works in construction

The article describes the environmental features of the production of pile works (noise, vibration), including by driving methods. They are the most unfavorable, the value of which exceeds the maximum permissible norms for noise and vibration by more than 2 times, and they are constantly growing from year to year, and this is the cause of many different diseases of people, including mental and neuralgic ones. In this regard, individual and collective methods of dealing with noise are recommended, as well as silent and low-noise methods of piling work, protected by the a.s.USSR and patents of the Republic of Belarus for inventions and utility models.

Recent advances in stabilization of mode-locked quantum dash lasers at 1.55 µm by dual-loop optical feedback

This paper reports the effectiveness of a variety of single- and dual-loop optical feedback arrangements on stability of self-mode-locked two-section quantum dash lasers emitting at ≈1.55 µm and operating at 21 GHz repetition rate. We describe reduction of RF linewidth and timing jitter using five distinct schemes, including single and dual loops with symmetric and asymmetric lengths, and with balanced and unbalanced feedback ratios. All feedback schemes described are effective in stabilizing the pulse trains from SML QDash lasers, but some require precisely tuned resonance between loop delay and laser cavity. We show balanced asymmetric dual-loop optical feedback is the most robust, cost-effective and low-noise method to stabilize and control pulses from mode-locked lasers and optoelectronic oscillators.

Proposal to Detect Dark Matter using Axionic Topological Antiferromagnets

Antiferromagnetically doped topological insulators (ATI) are among the candidates to host dynamical axion fields and axion polaritons, weakly interacting quasiparticles that are analogous to the dark axion, a long sought after candidate dark matter particle. Here we demonstrate that using the axion quasiparticle antiferromagnetic resonance in ATIs in conjunction with low-noise methods of detecting THz photons presents a viable route to detect axion dark matter with a mass of 0.7 to 3.5meV, a range currently inaccessible to other dark matter detection experiments and proposals. The benefits of this method at high frequency are the tunability of the resonance with applied magnetic field, and the use of ATI samples with volumes much larger than 1 mm^{3}.

Investigations of the electron phase space dynamics in triggered whistler wave emissions using low noise method

The evolution of the electron phase space structures during excitation of a triggered emission is investigated using the nonlinear method. Previous studies suggested that the dynamics of phase space structures due to nonlinear wave particle interactions is critical to the excitation of triggered emissions with frequency chirping. We introduce the use of the nonlinear method to simulate triggered emissions. Compared with full-f particle-in-cell method, the nonlinear method significantly reduces numerical noise, therefore making the phase space structures more identifiable. Specific to the simulation of triggered emissions, the nonlinear method also does not show numerical distortion of the distribution function due to reflecting particle boundary conditions. Using the nonlinear method, we show that during the main portion of the chirping element, the phase space structure roughly maintains a shape so that the resonant island moves a distance in phase space that is on the same order as its width during one phase space bounce period of deeply trapped particles, supporting that the interaction is non-adiabatic. We also demonstrate the disappearance of the phase space structure near the end of the chirping. Our work suggests that the nonlinear method could be very useful for the study of excitation of triggered emissions and to understand the mechanism of frequency chirping.

Using amino-labeled nucleotide probes for simultaneous single molecule RNA-DNA FISH.

Using amino-labeled oligonucleotide probes, we established a simple, robust and low-noise method for simultaneous detection of RNA and DNA by fluorescence in situ hybridization, a highly useful tool to study the large pool of long non-coding RNAs being identified in the current research. With probes either chemically or biologically synthesized, we demonstrate that the method can be applied to study a wide range of RNA and DNA targets at the single-cell and single-molecule level in cellular contexts.

Self-Powered Telemetric Torque Meter

This paper presents a self-powered telemetric torque meter. The idealized instrument uses strain gauge, telemetry, and LABVIEW graphic programming. The electronic transduction signal is transmitted by digital modulation from a remote transduction unit fixed to a rotation shaft to a base station sending signals to a personal computer (PC) by means of a virtual instrument developed in LABVIEW. The signal can also be delivered to other units besides the PC. The ZigBee/IEEE 802.15.4 protocol is the standard protocol for wireless communications and is highly used in industrial monitoring and control applications. A low-noise method for supplying the remote transduction unit components in the rotation shaft—using its rotating movement to generate the demanded energy—has also been developed. After extensive experimentation, the theoretical model seems to confirm the idea proposed. The system presented in this study is robust, precise, cost-effective, and has high-noise immunity even in abrasive and strong vibration environments.

Differential heterodyne detection with diffractive optics for multidimensional transient-grating spectroscopy

Heterodyne detection with a local oscillator generated by a diffractive optic provides good phase stability, but suffers from interfering single-beam-bleach signals. This interference is a problem in four-beam transient gratings, but becomes more severe in higher order transient gratings. A simple and low noise method to eliminate this interference is demonstrated in both a four-wave-mixing, first-order-transient-grating experiment and in a six-wave-mixing, second-order-transient-grating experiment.

High speed engine gas thermometry by Fourier-domain mode-locked laser absorption spectroscopy

We present a novel method for low noise, high-speed, real-time spectroscopy to monitor molecular absorption spectra. The system is based on a rapidly swept, narrowband CW Fourier-domain mode-locked (FDML) laser source for spectral encoding in time and an optically time-multiplexed split-pulse data acquisition system for improved noise performance and sensitivity. An acquisition speed of ~100 kHz, a spectral resolution better than 0.1 nm over a wavelength range of ~1335-1373 nm and a relative noise level of ~5 mOD (~1% minimum detectable base-e absorbance) are achieved. The system is applied for crank-angle-resolved gas thermometry by H(2)O absorption spectroscopy in an engine motoring at 600 and 900 rpm with a precision of ~1%. Influences of various noise sources such as laser phase and intensity noise, trigger and synchronization jitter in the electronic detection system, and the accuracy of available H(2)O absorption databases are discussed.

CAPACITIVELY COUPLED TELEMETRY FOR ROTATING SHAFTS

ABSTRACT, Capacitive coupling was investigated as a low noise method of transmitting electrical signals from a rotating shaft to a stationary receiver. Signals were transmitted across a capacitor in which one plate rotated with a shaft and the other was held stationary. The multiple channel capacitor design is presented. Transmitter and receiver design considerations are presented. Tests of transmission accuracy are discussed for transmission frequencies between 2 and 10 MHz.

Imaging devices using the charge-coupled concept

A unified treatment of the basic electrostatic and dynamic design of charge-coupled devices (CCD's) based on approximate analytical analysis is presented. Clocking methods and tradeoffs are discussed. Driver power dissipation and on-chip power dissipation are analyzed. Properties of noise sources due to charge input and transfer are summarized. Low-noise methods of signal extraction are discussed in detail. The state of the art for linear and area arrays is presented. Tradeoffs in area-array performance from a systems point of view and performance predictions are presented in detail. Time delay and integration (TDI) and the charge-injection device (CID) are discussed. Finally, the uses of the charge-coupled concept in infrared imaging are discussed.