Search

Based on the conventional beamforming (CBF), some algorithms for far-field sound source identification have been proposed in the past few decades. Typically, the functional beamforming (FBF) and the deconvolution methods, such as CLEAN, CLEAN with source coherence (CLEAN-SC), CLEAN-SC with compressed grids (CLEAN-SC-CG), CLEAN with cross spectral matrix function (CLEAN-CSM), High-resolution CLEAN-SC (HR-CLEAN-SC), are frequently mentioned and their advantages are widely discussed in the previous literatures. To assess their efficacy and suitability in engineering applications, with a focus on spatial resolution, computational efficiency, and dynamic range, a comparative study by locating two types of sound sources is carried out. The first scenario represents the case where the distance between two sound sources is smaller than the Rayleigh limit, while the second scenario represents the situation involving multiple sound sources, such as four or more complex sound sources. The analysis demonstrates that CBF, CLEAN, and CLEAN-SC cannot surpass the Rayleigh limit. However, FBF, CLEAN-SC-CG, CLEAN-CSM, and HR-CLEAN-SC have the potential to overcome it. In FBF, the grid mismatch results in a compromise between its dynamic range and source strength estimation. Meanwhile, HR-CLEAN-SC requires prior knowledge of the number of sound sources, which is challenging in applications. Because of superiority in the fundamental acoustic image and searching strategy, CLEAN-CSM and CLEAN-SC-CG exhibits superior features compared to the others. By compressing the number of grids, the CLEAN-SC-CG can improve the computational efficiency up to at least 46%. By constructing the cross spectral matrix function related to the real source, CLEAN-CSM uses the power function to simultaneously enhance the spatial resolution, dynamic range and source strength estimation. The conclusions are further validated through sound-source identification experiments involving two loudspeakers and an engine. The findings presented in this paper serve to guide the selection of suitable approaches for multi-sound source identification in engineering applications. [ABSTRACT FROM AUTHOR]

This investigation aimed to optimize gradient positioning for radiochromic film calibration to facilitate a uniform distribution of calibration points. The study investigated the influence of various parameters on gradient dose profiles generated by a physical wedge, assessing their impact on the field's dose dynamic range, a scalar quantity representing the span of absorbed doses. Numerical parameterization of the physical wedge profile was used to visualize and quantify the impact of field size, depth, and energy on the dynamic range of dose gradients. This concept enabled the optimization of the gradient positioning and estimation of the necessary number of exposures for the desired calibration dose range. An optimization algorithm based on histogram bin height minimization was developed and presented. The maximum dynamic range was achieved with a 20 ×$\times$ 20 cm2$\textrm {cm}^{2}$ field size at 5 cm depth. Optimization of wedge gradient positioning yielded the most uniform dose distribution with 7 exposures for the [1,10] Gy range and 8 exposures for the [1,20] Gy range. Film calibration using gradients centered at 1.6, 3, 3.5, and 7 Gy central axis (CAX), obtained through optimized gradient positioning, was showcased. The presented work demonstrates the potential for an improved film calibration process, with efficient material utilization and enhanced dosimetric accuracy for clinical applications. While the method was described for the use of a physical wedge, the methodology can be easily extended to the use of a more convenient dynamic wedge. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Astigmatic defocus sensor is a very simple and easy technique for measuring the amount of defocus (deviation from the focal plane) present in an optical beam. The approach uses a cylindrical lens to introduce astigmatism into the beam and also focus the beam. The measure of the intensity at the focal plane is then used to find out the amount of defocus present in the beam. In this paper, we provide a theoretical discussion on the astigmatic defocus sensor, which is further validated through simulation results. The performance of the astigmatic defocus sensor in terms of sensitivity, crosstalk and dynamic range is studied. Further, the process of optimization of the sensor in terms of the above parameters is also put forward. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shenzhen University Science & Engineering is the property of Editorial Department of Journal of Shenzhen University Science & Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A single-photon avalanche diode (SPAD) is a photon-counting sensor renowned for its exceptional single-photon sensitivity. One significant feature of SPADs is their non-linear response to light, making them ideal for high-dynamic range imaging applications. In SPAD imaging, the photon detection mode, which depends on the quenching method employed, is crucial for optimizing image quality and dynamic range. This paper examines the free-running and gating imaging modes, evaluating their impacts on photon capture and saturation limits. Given that the number of incident photons follows a Poisson distribution, we introduce an innovative imaging-quenching model based on statistical mathematics. We designed and fabricated two SPAD imaging sensors using 180 nm CMOS technology. Image processing and evaluation were conducted using a mapping method. Our results show that in low-light conditions, the gating mode surpasses the free-running mode in the signal-to-noise ratio (SNR). However, the free-running mode exhibits a saturation limit of more than an order of magnitude higher than that of the gating mode, demonstrating its superior capability to handle a broader range of light intensities. This paper provides a thorough analysis of the differences between the two imaging methods, incorporating the theoretical mathematical model, circuit characteristics, and computed imaging quality. [ABSTRACT FROM AUTHOR]

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes the design of 1.2-1.3 GHz, 2.5-3 GHz and 5.4-5.8 GHz MMIC voltage variable attenuator (VVA) realized using 0.25 μm GaAs pHEMT technology. It is a wideband voltage variable attenuator as it covers entire radar frequency bands. It provides a minimum attenuation of 2 dB in L and S-Band and 3 dB in C-Band and maximum attenuation of 72 dB in L-Band, 60 dB in S-Band and 47 dB in C-Band with attenuation flatness of 3 dB in L and S-Band and 1 dB in CBand. The phase response of the attenuator is also shown in this paper. The attenuator is perfectly matched with source and load impedances. It shows full-band stability. By convention, noise figure is equal to attenuation. The novelty of this proposed design is source controlled attenuator using gm-reduction and double active termination techniques with noise figure less than attenuation. These techniques increase the dynamic range of attenuation and reduce noise figure also. The double active termination technique also contributes in reducing noise figure below each attenuation level. It is necessary to keep noise figure below attenuation because the attenuator will be used in RF front-end of radar receiver. By keeping noise figure below attenuation, sensitivity of radar receiver will improve. Input 1 dB compression point of the proposed attenuator at maximum attenuation are at -4.3 dBm in L-Band, -5.9 dBm in S-Band and -5.3 dBm in C-Band and OIP3 at minimum attenuation are at -4.4 dBm in L-Band, -4.6 dBm in S-Band and -5 dBm in C-Band. The ideal and post-layout simulation results are presented in this paper. Figure of merit of the proposed attenuator is 280 in LBand, 70.3 in S-Band and 78.54 in C-Band. The attenuator can be used in single target tracking radar as well as in T/R module of AESA radar. [ABSTRACT FROM AUTHOR]

AbstractObjectiveDesignStudy sampleResultsConclusionThe dynamic range (DR) available to the patient is a central parameter to determine speech intelligibility in quiet.In this retrospective study, the DR for the Vibrant Soundbridge implanted in individual patients was calculated using in situ thresholds of the patients and technical data of the implant system. The average DR across frequencies (0.5, 1, 2, 4 kHz) was correlated with the patients’ assigned word recognition score (WRS) in quiet.A data set of 66 cases (4 bilateral and 2 revised cases) from 60 implanted patients between 14.3–81.8 years were analysed.The relationship between DR and WRS was described by a sigmoidal growth function with R2=0.6371 and a maximum WRS (upper asymptote) of 93.5%. Word recognition scores in quiet improved with increasing DR. A significant shift in performance was detected from DR bin 2 (10–20 dB, median WRS 55%) to bin 3 (20–30 dB, median WRS 80%) and from DR bin 4 (30–40 dB, median WRS 82.5%) to bin 5 (40–50 dB, median WRS 90%).A minimum DR of 20 dB can yield sufficient speech intelligibility in quiet in implanted patients, however, an optimum DR is suggested to be 40 dB. [ABSTRACT FROM AUTHOR]

A near‐eye display technology, Anamorphic‐XRTM, incorporating imaging waveguides is described. Developed for multiple applications since 2011, unique light manipulation capabilities and highly compact form factors are achievable. Catadioptric anamorphic optics and polarisation management are used to sidestep limitations of conventional VR lens and AR waveguide displays, enhancing performance and manufacturability. Simulations and measurements indicate an achievable specification of 90º field‐of‐view at 60ppd; >2000 nits/lumen; 80% polarised light transmission; and >15mm eyebox at 18mm eye relief from a <4mm thick waveguide. A Hybrid Immersive Display is proposed, combining an anamorphic waveguide with a conventional VR display. [ABSTRACT FROM AUTHOR]

In many areas of engineering, the design of a new system usually involves estimating performance-related parameters from early stages of the project to determine whether a given solution will be compliant with the defined requirements. This aspect is particularly relevant during the design of satellite payloads, where the target environment is not easily accessible in most cases. In the context of Earth observation sensors, this problem has been typically solved with the help of a set of complex pseudo-empirical models and/or expensive laboratory equipment. This paper describes a more practical approach: the illumination conditions measured by an in-orbit payload are recreated on ground with the help of a replica of the same payload so the performance of another Earth observation sensor in development can be evaluated. The proposed method is specially relevant in the context of small satellites, as the possibility of having extra units devoted to these tasks becomes greater as costs are reduced. The results obtained using this method in an actual space mission are presented in this paper, giving valuable information that will help in further stages of the project. [ABSTRACT FROM AUTHOR]

Ion mobility spectrometry (IMS) has been widely studied and applied as an effective analytical technology for the on-site detection of volatile organic compounds (VOCs). Despite its superior selectivity compared with most gas sensors, its limited dynamic range is regarded as a major drawback, limiting its further application in quantitative measurements. In this work, we proposed a novel sample introduction method based on pulsed membrane adsorption, which effectively enhanced IMS's ability to measure analytes at higher concentrations. Taking N-methyl-2-pyrrolidone (NMP) as an example, this new sampling method expanded the dynamic range from 1 ppm to 200 ppm. The working principle and measurement strategy of this sampling method were also discussed, providing new insights for the design and application of IMS-based instruments. [ABSTRACT FROM AUTHOR]

Several new approaches to the measurement of intrinsic noise and dynamic characteristics of superconducting bolometers based on the RFTES technology are demonstrated. The developed methods were tested with an experimental 550–750 GHz sample at reading frequency of ~1.5 GHz at a temperature of 400 mK. The absorption of thin-film resistive coatings on sapphire and quartz substrates was studied, and the emissivity of the experimental heat source was estimated as ~14%. A shot noise source based on Al/AlOx/Al tunnel junction was developed, and the noise temperature of the 1.35–1.6 GHz buffer amplifier referred to the detector output was determined as ~20 K. The response time of RFTES with a hafnium film sized 6 × 2 × 0.08 μm was evaluated as ~3 μs via microwave heat modulation at the second resonance at ~4.2 GHz; the dynamic range at a modulation frequency of 10 kHz was more than 23 dB. The data obtained made it possible to determine the RFTES sensitivity as 1 × 1017 W/ ± 30%, that coincided with the theoretical value up to the measurement error. [ABSTRACT FROM AUTHOR]

The Shack–Hartmann wavefront sensor (SHWFS) is widely utilized for ocular aberration measurement. However, large ocular aberrations caused by individual differences can easily make the spot move out of the range of the corresponding sub-aperture in SHWFS, rendering the traditional centroiding method ineffective. This study applied a novel convolutional neural network (CNN) model to wavefront sensing for large dynamic ocular aberration measurement. The simulation results demonstrate that, compared to the modal method, the dynamic range of our method for main low-order aberrations in ocular system is increased by 1.86 to 43.88 times in variety. Meanwhile, the proposed method also has the best measurement accuracy, and the statistical root mean square (RMS) of the residual wavefronts is 0.0082 ± 0.0185 λ (mean ± standard deviation). The proposed method generally has a higher accuracy while having a similar or even better dynamic range as compared to traditional large-dynamic schemes. On the other hand, compared with recently developed deep learning methods, the proposed method has a much larger dynamic range and better measurement accuracy. [ABSTRACT FROM AUTHOR]

In this paper, a radio frequency energy harvesting system with a wide dynamic range rectifier is presented. This rectifier has two feedback and feedforward structures. These paths keep the rectifier's power conversion efficiency (PCE) high at different input powers and thus create a high dynamic range (DR). This rectifier also has better sensitivity. Advances in the rectifier contribute to more satisfactory results for the final system. The circuit is simulated with 180 nm TSMC CMOS technology at a frequency of 900 MHz. Also, a π-type input impedance matching network circuit is used. This circuit is matched at Pin = − 19.5 dBm and f = 900 MHz. In addition, an off-chip balun is utilized to convert the received single-ended signal to the differential one. The achieved PCE and DR are 86.03% and 9.76 dB, respectively, with a sensitivity of − 19.32 at 1 V output voltage. Furthermore, the overall circuit results indicate a PCE of 76.13%, a DR of 6.3 dB, and a sensitivity of − 18.75 dBm. [ABSTRACT FROM AUTHOR]

There are many different types of number-pulse code converters operating in real time, in which the result is formed during the arrival time of each input pulse. The relevance of the development of number-pulse functional converters with variable bit rate, which in many works are also called bit-stream devices, has recently been due to the development trend of intelligent sensors and the transfer of primary transformations of measurement information as close as possible to them. Sensor signals are often represented by pulse-number code, that is, in bit-stream form, which allows real functional transformation in a digital element base. The paper presents the design results of number-pulse functional converters with variable bit rate, which differ in better metrological characteristics compared to known devices. As a result, a version of the implementation of number-pulse functional converters with a variable bit rate device for dividing the number-pulse code into a parallel code that can work in binary and binary-decimal counting systems on the FPGA is presented. An assessment of its time characteristics and hardware costs was carried out, which confirms the effectiveness of the used principle of variable bit rate. Time analysis of implemented devices on the FPGA was carried out taking into account the accuracy of their transformation and dynamic range. A feature of the construction of devices based on the variable bit rate principle is the possibility of simply increasing the bit rate of structural elements. The expansion of the dynamic range on the input digital-pulse code occurs within theoretically any given limits. Therefore, it is advisable to determine the speed of digital-pulse functional converters depending on their dynamic range according to the input digital-pulse code with fixed (given) other metrological characteristics before the start of their physical implementation. [ABSTRACT FROM AUTHOR]

Given the efficiency of the residue number system in high-speed and low-power applications, a wide variety of moduli sets have been introduced in the literature. Selecting an appropriate moduli set is one of the most important issues of using a residue number system. Moduli sets can be evaluated by several factors such as dynamic range, balanced channels, fast and low-power modular operations, and efficient reverse converter. In this paper, 3- and 4-moduli sets are separately reviewed and compared from a different perspective. Furthermore, the most efficient 3- and 4-moduli sets are suggested. A new parameter for average delay comparison is introduced, which shows the delay of every bit in the dynamic range providing a fair comparison of moduli sets with different numbers of moduli. Our comparison showed that either balanced channels or the delay of computations are essential factors for designing an efficient new moduli set. [ABSTRACT FROM AUTHOR]

The use of RF harvesting as a power source for low-power systems, such as wearables, wireless sensor nodes, and Internet of Things, has gained attention. The primary obstacle to develop an effective RF-DC system has been the RF rectifier. The method most frequently employed in the design of RF-DC converters is called Cross-Coupled Differential Drive (CCDD). To enhance the DC output voltage, multistage systems are typically employed. In these designs, DC output will reach saturation as the number of stages rises. This is because the NMOS threshold voltage will rise if the bulk of the NMOS is connected to the lowest potential. An alternative is to employ the twin-well CMOS process, which is more expensive than the regular n-well process. A novel CMOS RF-DC converter is presented in this brief. The design is hybrid in the sense the first stage is designed using a standard CCDD, while the second and subsequent stages are designed exclusively with PMOS transistors. This allows the use of the n-well process during fabrication. With CADENCE Virtuoso in $0.18~\mu \text{m}$ TSMC CMOS technology, the suggested design’s functionality is verified. The design is functional and achieves 45% efficiency and a power dynamic range of 23dB for power conversion efficiency (PCE) >20%, according to simulation findings.

Video imaging in open environments faces several problems such as the haze problem. Haze has a degradation effect on images. To enhance the video quality, we use a dual-transmission-map dehazing algorithm. We work on two video sequences: a Near Infrared (NIR) sequence and a visible sequence. We modify this dual-transmission-map dehazing algorithm by applying pre-processing on frames before the dehazing process to enhance the frame quality. All frames may have some noise or limited dynamic range due to sensor measurement errors that can be amplified in the haze removal process if ignored. We use different types of image enhancement techniques to either remove noise or control the dynamic range before the dehazing process. The dehazing algorithm can be implemented using a dual-transmission map depending on the Dark Channel Prior (DCP) method. Gradient-domain guided filtering is used to refine the two obtained transmission maps to obtain the best results for the dehazed frames. We investigate the effect of a regularization parameter ω on the visible and NIR dehazed frames without and with enhancement techniques. Results for visible video are more obvious than those for NIR video, because hazy visible frames have a large amount of haze compared to hazy NIR frames. We use the Peak Signal-to-Noise Ratio (PSNR) and correlation between hazy and dehazed frames after the dehazing process as evaluation metrics for the proposed algorithm. The proposed algorithm provides good results in the enhancement of two types of video as proved by the spectral entropy of dehazed frames. [ABSTRACT FROM AUTHOR]

Background: No single marker of bladder cancer (BC) exists in urine samples with sufficient accuracy for disease diagnosis and treatment monitoring. The multiplex Oncuria BC assay noninvasively quantifies the concentration of 10 protein analytes in voided urine samples to quickly generate a unique molecular profile with proven BC diagnostic and treatment-tracking utility. Test adoption by diagnostic and research laboratories mandates reliably reproducible assay performance across a variety of instrumentation platforms used in different laboratories. Methods: We compared the performance of the clinically validated Oncuria BC multiplex immunoassay when data output was generated on three different analyzer systems. Voided urine samples from 36 subjects (18 with BC and 18 Controls) were reacted with Oncuria test reagents in three 96-well microtiter plates on Day 1, and consecutively evaluated on the LED/image-based MagPix, and laser/flow-based Luminex 200 and FlexMap 3D (all xMAP instruments from Luminex Corp., Austin, TX) on Day 2. The BC assay uses magnetic bead-based fluorescence technology (xMAP, Multi-analyte profiling; Luminex) to simultaneously quantify 10 protein analytes in urine specimens [i.e., angiogenin (ANG), apolipoprotein E (ApoE), carbonic anhydrase IX (CA9), CXCL8/interleukin-8 (IL-8), matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-10 (MMP-10), serpin A1/alpha-1 anti-trypsin (A1AT), serpin E1/plasminogen activator inhibitor-1 (PAI-1), CD138/syndecan-1 (SDC1), and vascular endothelial growth factor-A (VEGF-A)]. All three analyzers quantify fluorescence signals generated by the Oncuria assay. Results: All three platforms categorized all 10 analytes in identical samples at nearly identical concentrations, with variance across systems typically < 5%. While the most contemporary instrument, the FlexMap 3D, output higher raw fluorescence values than the two comparator systems, standard curve slopes and analyte concentrations determined in urine samples were concordant across all three units. Forty-four percent of BC samples registered ≥ 1 analyte above the highest standard concentration, i.e., A1AT (n = 7/18), IL-8 (n = 5), and/or ANG (n = 2), while only one control sample registered an analyte (A1AT) above the highest standard concentration. Conclusion: Multiplex BC assays generate detailed molecular signatures useful for identifying BC, predicting treatment responsiveness, and tracking disease progression and recurrence. The similar performance of the Oncuria assay across three different analyzer systems supports test adaptation by clinical and research laboratories using existing xMAP platforms. Trial Registration: This study was registered at ClinicalTrials.gov as NCT04564781, NCT03193528, NCT03193541, and NCT03193515. [ABSTRACT FROM AUTHOR]

Two methods for compensation of polarization fading in microwave photonic links have been studied. Comparison of noise characteristics has been performed and factors limiting the dynamic range of microwave photonic link have been analyzed on an example of a link with an external remote electrooptic modulator. The possibility of reaching spurious-free dynamic range close to the shot-noise limit SFDR3 ≈ 116 dB Hz–2/3 has been demonstrated for 1000 m microwave photonic link. [ABSTRACT FROM AUTHOR]

Magnetorheological (MR) fluids have been known to react to magnetic fields of sufficient magnitudes. While in the presence of the field, the material develops a yield stress. The tunable property has made it attractive in, e.g., semi-active damper applications in the vibration control domain in particular. Within the context of a given application, MR fluids can be exploited in at least one of the fundamental operating modes (flow, shear, squeeze, or gradient pinch mode) of which the gradient pinch mode has been the least explored. Contrary to the other operating modes, the MR fluid volume in the flow channel is exposed to a non-uniform magnetic field in such a way that a Venturi-like contraction is developed in a flow channel solely by means of a solidified material in the regions near the walls rather than the mechanically driven changes in the channel's geometry. The pinch-mode rheology of the material has made it a potential candidate for developing a new category of MR valves. By convention, a pinch-mode valve features a single flow channel with poles over which a non-uniform magnetic field is induced. In this study, the authors examine ways of extending the dynamic range of pinch-mode valves by employing a number of such arrangements (stages) in series. To accomplish this, the authors developed a prototype of a multi-stage (three-stage) valve, and then compared its performance against that of a single-stage valve across a wide range of hydraulic and magnetic stimuli. To summarize, improvements of the pinch-mode valve dynamic range are evident; however, at the same time, it is hampered by the presence of serial air gaps in the flow channel. [ABSTRACT FROM AUTHOR]

A single-photon avalanche diode (SPAD) is a photon-counting sensor renowned for its exceptional single-photon sensitivity. One significant feature of SPADs is their non-linear response to light, making them ideal for high-dynamic range imaging applications. In SPAD imaging, the photon detection mode, which depends on the quenching method employed, is crucial for optimizing image quality and dynamic range. This paper examines the free-running and gating imaging modes, evaluating their impacts on photon capture and saturation limits. Given that the number of incident photons follows a Poisson distribution, we introduce an innovative imaging-quenching model based on statistical mathematics. We designed and fabricated two SPAD imaging sensors using 180 nm CMOS technology. Image processing and evaluation were conducted using a mapping method. Our results show that in low-light conditions, the gating mode surpasses the free-running mode in the signal-to-noise ratio (SNR). However, the free-running mode exhibits a saturation limit of more than an order of magnitude higher than that of the gating mode, demonstrating its superior capability to handle a broader range of light intensities. This paper provides a thorough analysis of the differences between the two imaging methods, incorporating the theoretical mathematical model, circuit characteristics, and computed imaging quality.

In underwater mobile visible light communication systems, the received optical power varies significantly when the transmission distance changes due to the large intrinsic absorption of water. This paper proposes an underwater mobile visible light communication technology based on Gain Feedback Control (GFC), which expands the dynamic range of both communication distance and Field of View (FOV). At a moving speed of 0.13 m/s, we achieved real-time duplex video transmission with adjustable communication distances between 0.9~5.2 m, data rates of 5.0 Mbit/s, video pixels of 800×600, and Frames Per Second (FPS) greater than zero. Compared with the system without GFC, the dynamic range of communication distance and receiving FOV angle has expanded to 5.3 and 2.8 times, respectively. In order to further verify the performance of the system, we measured the average scintillation index, data transmission outage probability, and Bit Error Rate (BER) of the system at different moving speeds. Within the dynamic range of communication distance, as the moving speed increases, the average scintillation index and BER correspondingly increase. However, even when the moving speed reaches 0.83 m/s, which is the maximum speed of the system, communication remains uninterrupted. Our results indicate that the system has good robustness and has good potential underwater mobile communication applications.

In view of the design difficulties of the vector impedance measurement module with a high dynamic range, this study designs a vector impedance measurement module based on the directional coupler using the directional coupler combined with the high-dynamic-range RF (Radio Frequency) logarithmic amplifier. The hardware and software design framework is given, the mathematical principle of the module is deduced, and the experimental verification and testing of the module are completed. The design makes full use of the characteristics of directional coupler, and the test system is small in size, good in scalability, fast in test speed and high in efficiency. The design can also be extended to a monitoring and measuring module, which can be used in communication equipment as an antenna monitoring component or power intensity control component of communication transmitter. After the verification, a number of practical applications have been developed using this design scheme. The high dynamic range of the proposed designed covers the application scenarios from 20~400 W, and obtains good application effect, which proves that the proposed design has good application, expansibility and high practical value. [ABSTRACT FROM AUTHOR]

Background and Hypothesis Despite accounting for significant disease morbidity in schizophrenia, the neuropathological basis of negative symptoms remains poorly understood and options for treatment limited. Our recent study identified robust associations between diminished auditory cortex (AC) dynamic range and social functioning impairments and negative symptoms in first episode psychosis (FESz). The current investigation examined the progression of these relationships 4–8 months from baseline testing. Study Design Twenty-six FESz and 38 healthy controls (HC) were tested at baseline and follow-up. Magnetoencephalography (MEG) was recorded during binaural presentation of tones (75, 80, and 85 dB). Assessments included the MATRICS cognitive consensus battery (MCCB) and Global Functioning: Role and Social scales (GFR/GFS) and the Positive and Negative Syndrome Scale. Study Results Overall, FESz exhibited a blunted response to increasing tone intensity relative to HC. While this deficit did not change over time at the group level, recovery of right hemisphere AC dynamic range (85–75 dB response) among FESz individuals was associated with reductions in negative symptoms (ρ = −0.50). Diminished dynamic range was also associated with impaired GFS (ρ = 0.65), GFR (ρ = 0.51), and MCCB (ρ = 0.49) at baseline and increased negative symptoms at baseline (ρ = −0.53) and follow-up (ρ = −0.51). Conclusion Despite persistent dynamic range impairment in FESz as a group, individual recovery of this AC response property was associated with significant reduction in negative symptoms. Identification of a functional neural deficit that tracts progression of negative symptoms during a critical period for disease modification is essential to the management of these devastating and historically treatment refractory symptoms. [ABSTRACT FROM AUTHOR]

Background and Objectives: To analyze mapping changes in dynamic range (DR) and neural response threshold (NRT) as prognostic factors for cochlear implant (CI). To analyze whether postoperative speech perception performance could be predicted using DR change and initial NRT. Subjects and Methods: The speech comprehension data of 33 patients with CI were retrospectively analyzed after 1, 3, 6, and 12 months of device use. All subjects were adult, postlingually hearing-impaired, and Cochlear Nucleus CI users. Speech perception performance was evaluated using aided pure tone audiometry, consonant, vowel, one-word, two-word, and sentence tests. Results: The averages of initial NRT and DR changes were 197.8±25.9 CU (104–236) and 22.2±18.4 CU (-15–79), respectively. The initial DR was 40.8±16.6 CU. The postoperative DR was 50.3±16.4 CU at 3 months, 58±12.3 CU at 6 months, and 62.9±10.4 CU at 12 months. A gradual increase of DR was observed during the first year of CI. Compared with the initial DR, significant increases in DR were observed at 3 (p<0.05), 6 (p<0.001), and 12 (p<0.001) months. Compared with initial speech performance outcomes, a significant gain in all performance outcomes was achieved at 12 months (p<0.001). Conclusions: Patients with low NRT after CI surgery could initially set DR to a wider range and had better final speech perception outcomes. Conversely, patients with high NRT after CI surgery had to set up a gradual increase in DR while adjusting the T-C level, and the final speech perception outcomes were worse. DR and NRT, the main CI mapping variables, can help predict prognosis related to speech perception outcomes after CI surgery. In conclusion, the post-CI speech perception is better with a lower initial NRT, wider final DR, or younger age. [ABSTRACT FROM AUTHOR]

Ion mobility spectrometry (IMS) has been widely studied and applied as an effective analytical technology for the on-site detection of volatile organic compounds (VOCs). Despite its superior selectivity compared with most gas sensors, its limited dynamic range is regarded as a major drawback, limiting its further application in quantitative measurements. In this work, we proposed a novel sample introduction method based on pulsed membrane adsorption, which effectively enhanced IMS’s ability to measure analytes at higher concentrations. Taking N-methyl-2-pyrrolidone (NMP) as an example, this new sampling method expanded the dynamic range from 1 ppm to 200 ppm. The working principle and measurement strategy of this sampling method were also discussed, providing new insights for the design and application of IMS-based instruments.

The Shack–Hartmann wavefront sensor (SHWFS) is widely utilized for ocular aberration measurement. However, large ocular aberrations caused by individual differences can easily make the spot move out of the range of the corresponding sub-aperture in SHWFS, rendering the traditional centroiding method ineffective. This study applied a novel convolutional neural network (CNN) model to wavefront sensing for large dynamic ocular aberration measurement. The simulation results demonstrate that, compared to the modal method, the dynamic range of our method for main low-order aberrations in ocular system is increased by 1.86 to 43.88 times in variety. Meanwhile, the proposed method also has the best measurement accuracy, and the statistical root mean square (RMS) of the residual wavefronts is 0.0082 ± 0.0185 λ (mean ± standard deviation). The proposed method generally has a higher accuracy while having a similar or even better dynamic range as compared to traditional large-dynamic schemes. On the other hand, compared with recently developed deep learning methods, the proposed method has a much larger dynamic range and better measurement accuracy.

Generating ultra-low currents using resistors is impractical especially in integrated circuits due to the wasting of much area associated with the required very large resistors. In this paper, three ultra-low current sources that are suitable for biomedical and implantable applications are proposed. The generated currents are in the nanoampere range. One of the proposed current sources depends on a modification of the conventional Widlar MOS current source in which a tunable subthreshold-region operated transistor is utilized as a controlled resistance. The proposed current source is suitable for low-voltage and low-power applications. Also, two digitally controlled current sources (DCCSs) are proposed. The DCCSs find a wide variety of applications in digital-to-analog converters, implantable microstimulators, and charge pumps. The three proposed current sources are analyzed quantitatively. They are also verified by simulation adopting the 45 nm CMOS Predictive Technology Model (PTM) with a power-supply voltage, VDD, equal to 1 V.

Neuromorphic computing can efficiently handle data‐intensive tasks and address the redundant interaction required by von Neumann architectures. Synaptic devices are essential components for neuromorphic computation. 2D phosphorene, such as violet phosphorene, show great potential in optoelectronics due to their strong light‐matter interactions, while current research is mainly focused on synthesis and characterization, its application in photoelectric devices is vacant. Here, the authors combined violet phosphorene and molybdenum disulfide to demonstrate an optoelectronic synapse with a light‐to‐dark ratio of 106, benefiting from a significant threshold shift due to charge transfer and trapping in the heterostructure. Remarkable synaptic properties are demonstrated, including a dynamic range (DR) of > 60 dB, 128 (7‐bit) distinguishable conductance states, electro‐optical dependent plasticity, short‐term paired‐pulse facilitation, and long‐term potentiation/depression. Thanks to the excellent DR and multi‐states, high‐precision image classification with accuracies of 95.23% and 79.65% is achieved for the MNIST and complex Fashion‐MNIST datasets, which is close to the ideal device (95.47%, 79.95%). This work opens the way for the use of emerging phosphorene in optoelectronics and provides a new strategy for building synaptic devices for high‐precision neuromorphic computing. [ABSTRACT FROM AUTHOR]

The CITIUS detector is a next‐generation high‐speed X‐ray imaging detector. It has integrating‐type pixels and is designed to show a consistent linear response at a frame rate of 17.4 kHz, which results in a saturation count rate of over 30 Mcps pixel−1 when operating at an acquisition duty cycle close to 100%, and up to 20 times higher with special extended acquisition modes. Here, its application for Bragg coherent diffraction imaging is demonstrated by taking advantage of the fourth‐generation Extremely Brilliant Source of the European Synchrotron (ESRF‐EBS, Grenoble, France). The CITIUS detector outperformed a photon‐counting detector, similar spatial resolution being achieved (20 ± 6 nm versus 22 ± 9 nm) with greatly reduced acquisition times (23 s versus 200 s). It is also shown how the CITIUS detector can be expected to perform during dynamic Bragg coherent diffraction imaging measurements. Finally, the current limitations of the CITIUS detector and further optimizations for coherent imaging techniques are discussed. [ABSTRACT FROM AUTHOR]

Dynamic range and spurious-free dynamic range are two of the most critical performance indexes in the field of radio frequency (RF). However, the definitions of both the indexes are ambiguous, and their characterization ability is insufficient, resulting in unfair, and even mutually incompatible, performance evaluation in practice. In this study, a new index named radio frequency distortion dynamic range and its corresponding evaluation method are proposed to achieve a fair and detailed dynamic range evaluation by unifying the existing definitions and improving the performance resolution ability. First, the sliding threshold selection method is introduced to replace the classification-based method of dynamic range definition to characterize more details of the dynamic range. Second, a dynamic range evaluation method of "performance body" is proposed to obtain a more comprehensive evaluation by generalizing the current evaluation from being based on a single condition to the one based on scanning critical conditions. Experiments show that the proposed radio frequency distortion dynamic range index with the proposed evaluation method reduces the ambiguity of dynamic range evaluation and can distinguish the performance difference that the current indexes cannot do. [ABSTRACT FROM AUTHOR]

Current-sensing topology with multi resistors in series has limitations in improving the dynamic range of current acquisition, so a sensing topology with multi resistors in parallel is proposed. The overcurrent state of a parallel shunt circuit cannot be latched, resulting in protection hiccups. A dual threshold-detection circuit is designed to achieve protection state latching and self-recovery. The rectified mean circuit is applied for overcurrent magnitude detection and its validity is proved. But the delay and ripple of the output waveform of the rectified mean circuit may also cause protection hiccups. Combining Fourier series representation, Fourier transform and inverse transform, the time domain expressions of the output of the rectified mean circuit for three common waveforms are obtained. Furthermore, the estimation formulas for the residual ripple amplitude of the three waveforms are derived. In an experiment, the protection hiccup issue in parallel sensing topology was eliminated, while the time constants and hysteresis ratios of the protection circuits were properly set according to theoretical calculation results. With five parallel sensing resistors, the ratio of the maximum to minimum range of the single current channel reaches 1.28 × 10 4 , which is higher than counterparts with multiple series sensing resistors. The advantages of parallel sensing topology in improving dynamic range are confirmed. [ABSTRACT FROM AUTHOR]

Copyright of Study on Optical Communications / Guangtongxin Yanjiu is the property of Study on Optical Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Conventional designs of an avalanche photodiode (APD) have been based on a planar p–n junction since the 1960s. APD developments have been driven by the necessity to provide a uniform electric field over the active junction area and to prevent edge breakdown by special measures. Most modern silicon photomultipliers (SiPM) are designed as an array of Geiger-mode APD cells based on planar p–n junctions. However, the planar design faces an inherent trade-off between photon detection efficiency and dynamic range due to loss of an active area at the cell edges. Non-planar designs of APDs and SiPMs have also been known since the development of spherical APDs (1968), metal-resistor-semiconductor APDs (1989), and micro-well APDs (2005). The recent development of tip avalanche photodiodes (2020) based on the spherical p–n junction eliminates the trade-off, outperforms the planar SiPMs in the photon detection efficiency, and opens new opportunities for SiPM improvements. Furthermore, the latest developments in APDs based on electric field-line crowding and charge-focusing topology with quasi-spherical p–n junctions (2019–2023) show promising functionality in linear and Geiger operating modes. This paper presents an overview of designs and performances of non-planar APDs and SiPMs. [ABSTRACT FROM AUTHOR]

We propose a six-axis force sensor with a simple structure that can measure small forces while affording a high load capacity. For a robot to perform complex motions in an unknown environment, the force sensor used must exhibit a high resolution and high load rating. Various studies have been conducted to simultaneously satisfy these two requirements. However, the high processing cost due to the complicated sensor structure is problematic. Therefore, we develop a column-type high dynamic range (HDR) six-axis force sensor using two types of strain gauges. The sensor was composed of a drawn pipe to solve structural problems that arise during manufacturing. By attaching strain gauges to the surface of the drawn pipe, the forces and torques in the six axes can be measured. HDR measurement was realizable using a semiconductor strain gauge for small loads and a metallic foil strain gauge for large loads. Based on the simulation results, the rated loads of the sensor were 1400 N in the Fx and Fy directions, 9000 N in the Fz direction, and 120 Nm in the Mx, My, and Mz directions. The performance of the fabricated force sensor was evaluated. The maximum nonlinearity errors of the semiconductor strain gauge and the metallic foil strain gauges were 1.21% and 1.81%, respectively. In addition, when comparing the S/N ratios, the minimum measurable values were 0.035 N and 0.13 N for Fy and Fz, respectively. [ABSTRACT FROM AUTHOR]

This paper presents static and dynamic theoretical analysis of a new Operational Transconductance Amplifier (OTA) dedicated to low-voltage and low-power applications. High linearity is obtained using signal attenuation for rail-to-rail operation. Design, layout and post-layout simulations have been carried-out with Cadence Virtuoso in a 0.18µm CMOS technology. Post-Layout Simulation (PLS) demonstrates proper operation down to ± 0.75 V supply voltage with a high open loop small-signal voltage gain of 58.26dB, a unity gain frequency of 18MHz and a total harmonic distortion of -66.55dB at 100 kHz for a peak-to-peak input voltage of 0.8V. Based on this circuit, two applications have been successfully demonstrated: on the one side, a 5th order Butterworth G mC filter and, on the other side, a voltage mode instrumentation amplifier. [ABSTRACT FROM AUTHOR]