Signal Dynamic Range Research Articles

Nonparametric estimation of the dynamic range of music signals

SummaryThe dynamic range is an important parameter which measures the spread of sound power, and for music signals it is a measure of recording quality. There are various descriptive measures of sound power, none of which has strong statistical foundations. We start from a nonparametric model for sound waves where an additive stochastic term has the role of catching transient energy. This component is recovered by a simple rate‐optimal kernel estimator that requires a single data‐driven tuning parameter. The distribution of its variance is approximated by a consistent random subsampling method that is able to cope with the massive size of the typical dataset. Based on the latter, we propose a statistic, and an estimation method that is able to represent the dynamic range concept consistently. The behaviour of the statistic is assessed based on a large numerical experiment where we simulate dynamic compression on a selection of real‐world music signals. Application of the method to real data also shows how the proposed method can predict subjective experts' opinions about the hifi quality of a recording.

Comparison of the leading-edge timing walk in pulsed TOF laser range finding with avalanche bipolar junction transistor (BJT) and metal-oxide-semiconductor (MOS) switch based laser diode drivers.

Timing walk error in pulsed time-of-flight based laser range finding was studied using two different types of laser diode drivers. The study compares avalanche bipolar junction transistor (BJT) and metal-oxide-semiconductor field-effect transistor switch based laser pulse drivers, both producing 1.35 ns current pulse length (full width at half maximum), and investigates how the slowly rising part of the current pulse of the avalanche BJT based driver affects the leading edge timing walk. The walk error was measured to be very similar with both drivers within an input signal dynamic range of 1:10 000 (receiver bandwidth of 700 MHz) but increased rapidly with the avalanche BJT based driver at higher values of dynamic range. The slowly rising part does not exist in the current pulse produced by the metal-oxide-semiconductor (MOS) based laser driver, and thus the MOS based driver can be utilized in a wider dynamic range.

Potential of Sentinel-1 Radar Data for the Assessment of Soil and Cereal Cover Parameters

The main objective of this study is to analyze the potential use of Sentinel-1 (S1) radar data for the estimation of soil characteristics (roughness and water content) and cereal vegetation parameters (leaf area index (LAI), and vegetation height (H)) in agricultural areas. Simultaneously to several radar acquisitions made between 2015 and 2017, using S1 sensors over the Kairouan Plain (Tunisia, North Africa), ground measurements of soil roughness, soil water content, LAI and H were recorded. The NDVI (normalized difference vegetation index) index computed from Landsat optical images revealed a strong correlation with in situ measurements of LAI. The sensitivity of the S1 measurements to variations in soil moisture, which has been reported in several scientific publications, is confirmed in this study. This sensitivity decreases with increasing vegetation cover growth (NDVI), and is stronger in the VV (vertical) polarization than in the VH cross-polarization. The results also reveal a similar increase in the dynamic range of radar signals observed in the VV and VH polarizations as a function of soil roughness. The sensitivity of S1 measurements to vegetation parameters (LAI and H) in the VV polarization is also determined, showing that the radar signal strength decreases when the vegetation parameters increase. No vegetation parameter sensitivity is observed in the VH polarization, probably as a consequence of volume scattering effects.

Compensation of the nonuniformity of sensitivity for the multielement infrared photodetector

Application of spectral devices for the detection of small concentrations of substances presents high demands on the signal dynamic range. Commonly used multielement photodetectors have a substantial nonuniformity of both sensitivity and dark signal that significantly narrows the dynamic range. For correction of such situation it was designed an amplifier with individual correction of gain and offset of a dark signal for each pixel that considerably enhances dynamic range and presents an ability to effectively detect weak signals.

A novel feed‐forward segmented digital automatic gain control algorithm for long‐term evolution digital radio‐over‐fibre systems

© 2017, The Institution of Engineering and Technology. This study describes a novel feed-forward segmented digital automatic gain control (FSD-AGC) algorithm for long term evolution (LTE) digital radio-over-fibre (DRoF) systems. It experimentally demonstrates the algorithm using a DRoF platform based on real-time field programmable gate arrays. The FSD-AGC algorithm is able to update power status accurately with a short delay (about 100 samples) and adjust the gain precisely by only one step. It can make full use of analogue-to-digital converter quantisation bits width without oversaturation and maintain a stable peak-to-average ratio to reduce the overall cost and energy consumption of digital links and to minimise the deterioration of error vector magnitude (EVM) in LTE systems. Compared with conventional solutions, the proposed algorithm shows significant improvement in the dynamic range (a 20 dB improvement is demonstrated experimentally) of 4G-LTE radio frequency signals in a DRoF system. This is a major step forward for the future commercialisation of DRoF systems for 4G and 5G network deployments. Meanwhile, FSD-AGC can be applied in both LTE time division duplexing and frequency division duplexing signals. Experimental results have shown a mean EVM of the DRoF system below 4.5%, which is well below the 8% required by 3rd generation partnership project.

A simple encoding method for Sigma-Delta ADC based biopotential acquisition systems

Sigma Delta analogue-to-digital converters allow acquiring the full dynamic range of biomedical signals at the electrodes, resulting in less complex hardware and increased measurement robustness. However, the increased data size per sample (typically 24 bits) demands the transmission of extremely large volumes of data across the isolation barrier, thus increasing power consumption on the patient side. This problem is accentuated when a large number of channels is used as in current 128–256 electrodes biopotential acquisition systems, that usually opt for an optic fibre link to the computer. An analogous problem occurs for simpler low-power acquisition platforms that transmit data through a wireless link to a computing platform. In this paper, a low-complexity encoding method is presented to decrease sample data size without losses, while preserving the full DC-coupled signal. The method achieved a 2.3 average compression ratio evaluated over an ECG and EMG signal bank acquired with equipment based on Sigma-Delta converters. It demands a very low processing load: a C language implementation is presented that resulted in an 110 clock cycles average execution on an 8-bit microcontroller.

ICESat/GLAS Altimetry Measurements: Received Signal Dynamic Range and Saturation Correction.

NASA's Ice, Cloud, and land Elevation Satellite (ICESat), which operated between 2003 and 2009, made the first satellite-based global lidar measurement of Earth's ice sheet elevations, sea-ice thickness and vegetation canopy structure. The primary instrument on ICESat was the Geoscience Laser Altimeter System (GLAS), which measured the distance from the spacecraft to Earth's surface via the roundtrip travel time of individual laser pulses. GLAS utilized pulsed lasers and a direct detection receiver consisting of a silicon avalanche photodiode (Si APD) and a waveform digitizer. Early in the mission, the peak power of the received signal from snow and ice surfaces was found to span a wider dynamic range than planned, often exceeding the linear dynamic range of the GLAS 1064-nm detector assembly. The resulting saturation of the receiver distorted the recorded signal and resulted in range biases as large as ~50 cm for ice and snow-covered surfaces. We developed a correction for this "saturation range bias" based on laboratory tests using a spare flight detector, and refined the correction by comparing GLAS elevation estimates to those derived from Global Positioning System (GPS) surveys over the calibration site at the salar de Uyuni, Bolivia. Applying the saturation correction largely eliminated the range bias due to receiver saturation for affected ICESat measurements over Uyuni and significantly reduced the discrepancies at orbit crossovers located on flat regions of the Antarctic ice sheet.

From single SQUID to superconducting quantum arrays

Superconducting quantum arrays (SQAs) capable of providing highly linear voltage response to magnetic signal and high dynamic range have been suggested and developed. Base elements of the arrays, quantum cells, were devised and studied in detail. Using niobium process, SQAs with different number of the cells and prototypes of the SQA-based broadband active electrically small antennas were fabricated and tested.

Time‐division polynomial pre‐distorter for linearisation of 1.5 T MRI power amplifier

A time-division polynomial (TDP) model is proposed for modelling and linearising a 1.5 T magnetic resonance imaging (MRI) power amplifier (PA) with strong non-linearity in high input signal dynamic range. In order to demonstrate the merit of this non-linear model, a 64 dBm 1.5 T MRI PA (63.89 MHz) and two different Sinc-pulse signals are used in modelling and linearisation measurements. The TDP is compared with the conventional non-memory polynomial (NMP) and no digital pre-distortion for the 1.5 T MRI PA, which is driven by test signal with 2 ms time length and 2% duty cycle. The proposed TDP leads to up to 9 dB improvement in the normalised mean square error compared with the NMP in two different test signals. More importantly, TDP illustrates significantly better reduction in amplitude modulation/amplitude modulation (AM/AM) and amplitude modulation/phase modulation (AM/PM) conversion compared with the NMP.

Prototype of Field Waveform Digitizer for BaF2Detector Array at CSNS-WNS

At the China spallation neutron source-white neutron sources (CSNS-WNS), the BaF2 (barium fluoride) detector array in planning is designed for neutron capture cross section measurements with high accuracy and efficiency. Once proton beam collides with the spallation target, the neutrons will fly from the target to specimen surrounded by BaF2 array and produce cascaded $\gamma $ rays eventually. The time of flight (TOF) corresponds to the neutron energy. To identify $\gamma $ signals from the high $\alpha $ -particle background, pulse shape discrimination (PSD) technique is usually used according to the ratio of fast to slow component in the signal. Waveform digitization is a valid supporting technology for PSD. In order to precisely obtain the wave and time information carried by detector signal, and to maximally cover the signal dynamic range, a universal digitizer with 1 GSps sampling rate and 12-b resolution has been designed based on a 3U PXIe platform in this paper. Besides waveform digitization, this customized digitizer also measures TOF precisely based on the digitized waveform data and technique of time-to-digital converting on field-programming gate array. Test results show that this digitizer can achieve good static and dynamic performance. The specification of effective number of bits is better than 9.43 b within 198 MHz. Digitizer proposed in this paper can meet the requirements for BaF2 spectrum at CSNS-WNS.

A simplified guide for charged aerosol detection of non-chromophoric compounds—Analytical method development and validation for the HPLC assay of aerosol particle size distribution for amikacin

Amikacin, an aminoglycoside antibiotic lacking a UV chromophore, was developed into a drug product for delivery by inhalation. A robust method for amikacin assay analysis and aerosol particle size distribution (aPSD) determination, with comparable performance to the conventional UV detector was developed using a charged aerosol detector (CAD). The CAD approach involved more parameters for optimization than UV detection due to its sensitivity to trace impurities, non-linear response and narrow dynamic range of signal versus concentration. Through careful selection of the power transformation function value and evaporation temperature, a wider linear dynamic range, improved signal-to-noise ratio and high repeatability were obtained. The influences of mobile phase grade and glassware binding of amikacin during sample preparation were addressed. A weighed (1/X2) least square regression was used for the calibration curve. The limit of quantitation (LOQ) and limit of detection (LOD) for this method were determined to be 5μg/mL and 2μg/mL, respectively. The method was validated over a concentration range of 0.05–2mg/mL. The correlation coefficient for the peak area versus concentration was 1.00 and the y-intercept was 0.2%. The recovery accuracies of triplicate preparations at 0.05, 1.0, and 2.0mg/mL were in the range of 100–101%. The relative standard deviation (Srel) of six replicates at 1.0mg/mL was 1%, and Srel of five injections at the limit of quantitation was 4%. A robust HPLC-CAD method was developed and validated for the determination of the aPSD for amikacin. The CAD method development produced a simplified procedure with minimal variability in results during: routine operation, transfer from one instrument to another, and between different analysts.

Adaptive Digital Predistortion Based on Hybrid Indirect Learning Structure with Variable Step-Size for Wideband HPA

Adaptive digital predistortion is one of the most promising linearization technique, which leads to more efficient and cost-effective high power amplifier (HPA). In this paper, a fast-converging variable step-size least mean square algorithm based on hybrid indirect learning structure is presented to provide an unbiased predistortion identification in the non-stationary signal condition for wideband HPA. By using a variable step-size strategy, the proposed identifying algorithm can adapt its learning rate according to the dynamic range of input signal. Thus, more stable learning convergence and lower steady-state mis-adjustment error are obtained simultaneously. A comprehensive theoretical analysis is presented, and some important results including learning stability, convergence behavior, and selection criteria for initialization parameter setting are derived. Both its superiority and robustness are well confirmed through extensive numerical simulations.

TOFFEE: a full custom amplifier-comparator chip for timing applications with silicon detectors

We report on the design of a full custom amplifier-comparator readout chip for silicon detectors with internal gain designed for precise timing applications. The ASIC has been developed in UMC 110 nm CMOS technology and is aimed to fulfill the CMS-TOTEM Precision Proton Spectrometer (CT-PPS) time resolution requirements (∼ 30 ps per detector plane). It features LVDS outputs and the signal dynamic range matches the requirements of the High Precision TDC (HPTDC) system. The preliminary measurements results with a test board are included.

Application of a nonradioactive assay for high throughput screening for inhibition of thyroid hormone uptake via the transmembrane transporter MCT8

Thyroid hormones (THs) play important roles in almost all physiological processes. High-throughput screening (HTS) assays are needed to screen the vast numbers of chemicals for their potential to disrupt TH signalling. The current work has confirmed the ability of a rapid assay to identify substances inhibiting TH uptake through monocarboxylate transporter (MCT) 8. Perturbation of MCT8 function results in significant developmental impairments, suggesting substances inhibiting MCT8 may be important developmental toxicants. We examined the accuracy and consistency of a recently described method to identify TH inhibitors via MCT8, using MDCK cells overexpressing human MCT8 gene. We confirmed the method detected T3 uptake in a concentration/time-dependent manner, and this effect was blocked by substances previous reported to block TH uptake via MCT8. Assay performance was assessed extensively and the system was found to have high signal dynamic range and Z' factor. The assay was also validated with a diverse set of training chemicals. This assay was then used to screen chemicals suspected to disrupt TH signalling. Other than bisphenol A (BPA), all substances tested were negative. Our results suggest that this assay could be part of a battery of screening assays to predict the potential thyroid disrupting activity of chemicals.

Carrier-less amplitude and phase modulated visible light communication system based on a constellation-shaping scheme

In this Letter, we propose a novel constellation-shaping carrier-less amplitude and phase (CAP) modulation scheme to alleviate the systematic nonlinearity in visible light communication (VLC) systems. A simple geometric transformation shaping method is employed to convert the normal square lattice constellation into multiple circular constellations. The feasibility and performance are investigated and experimentally demonstrated by a 1.25 Gb/s CAP-modulated VLC system. The results indicate that the circular constellation has better resistance to systematic nonlinearity compared with a rectangular constellation. The dynamic range of input signal peak-to-peak values promotes 20% at a low bias voltage nonlinear area and 50% at a high bias voltage nonlinear area. To the best of our knowledge, this is the first time constellation-shaping CAP has ever been reported in indoor high data rate VLC systems.

Covalently deposited dyes: a new chromogen paradigm that facilitates analysis of multiple biomarkers in situ

Multiplexed analysis of multiple biomarkers in a tissue sample requires use of reporter dyes with specific spectral properties that enable discrimination of signals. Conventional chromogens with broad absorbance spectra, widely used in immunohistochemistry (IHC), offer limited utility for multiplexed detection. Many dyes with narrow absorbance spectra, eg rhodamines, fluoresceins, and cyanines, potentially useful for multiplexed detection are well-characterized; however, generation of a chromogenic reagent useful for IHC analysis has not been demonstrated. Studies reported herein demonstrate utility of tyramine-chemistry for synthesis of a wide variety of new chromogenic dye conjugates useful for multiplexed in situ analysis using conventional light microscopes. The dyes, useful individually or in blends to generate new colors, provide signal sensitivity and dynamic range similar to conventional DAB chromogen, while enabling analysis of co-localized biomarkers. It is anticipated that this new paradigm will enable generation of a wide variety of new chromogens, useful for both research and clinical biomarker analysis that will benefit clinicians and patients.

Real-Time Video Transmission of Visible Light Communication Based on LED

In order to realize the video image transmission and the excellent lighting function of the visible light communication system, a LED-based visible light communication method and system is proposed. Based on the field programmable gate array (FPGA) hardware, the RS channel coding is applied to the visible light communication system. A pulse position decision algorithm is proposed, which is applied to the receiver of the visible light communication system to meet the error-free decision of the signal. The design of the system is based on the analog-to-digital conversion circuit, which provides a large signal dynamic range for the pulse position decision algorithm, and designs the LED driver based on the bias circuit to realize the fast broadband modulation of the signal. The test results show that the combined application of pulse position decision algorithm and Reed-Solomon codec can reduce the error of system signal and meet the real-time and reliable transmission of signal. The system can display the received video in real time from the receiver, and the whole system communication distance up to 5 m.

Validation of tumor protein marker quantification by two independent automated immunofluorescence image analysis platforms

AbstractProtein marker levels in formalin-fixed, paraffin-embedded tissue sections traditionally have been assayed by chromogenic immunohistochemistry and evaluated visually by pathologists. Pathologist scoring of chromogen staining intensity is subjective and generates low-resolution ordinal or nominal data rather than continuous data. Emerging digital pathology platforms now allow quantification of chromogen or fluorescence signals by computer-assisted image analysis, providing continuous immunohistochemistry values. Fluorescence immunohistochemistry offers greater dynamic signal range than chromogen immunohistochemistry, and combined with image analysis holds the promise of enhanced sensitivity and analytic resolution, and consequently more robust quantification. However, commercial fluorescence scanners and image analysis software differ in features and capabilities, and claims of objective quantitative immunohistochemistry are difficult to validate as pathologist scoring is subjective and there is no accepted gold standard. Here we provide the first side-by-side validation of two technologically distinct commercial fluorescence immunohistochemistry analysis platforms. We document highly consistent results by (1) concordance analysis of fluorescence immunohistochemistry values and (2) agreement in outcome predictions both for objective, data-driven cutpoint dichotomization with Kaplan–Meier analyses or employment of continuous marker values to compute receiver-operating curves. The two platforms examined rely on distinct fluorescence immunohistochemistry imaging hardware, microscopy vs line scanning, and functionally distinct image analysis software. Fluorescence immunohistochemistry values for nuclear-localized and tyrosine-phosphorylated Stat5a/b computed by each platform on a cohort of 323 breast cancer cases revealed high concordance after linear calibration, a finding confirmed on an independent 382 case cohort, with concordance correlation coefficients >0.98. Data-driven optimal cutpoints for outcome prediction by either platform were reciprocally applicable to the data derived by the alternate platform, identifying patients with low Nuc-pYStat5 at ~3.5-fold increased risk of disease progression. Our analyses identified two highly concordant fluorescence immunohistochemistry platforms that may serve as benchmarks for testing of other platforms, and low interoperator variability supports the implementation of objective tumor marker quantification in pathology laboratories.

A 10.2 mW multi-mode continuous-time ΔΣ ADC with 70–87 dB DR and 0.7–10 MHz bandwidth for TD-SCDMA and LTE digital receivers

This paper presents a low power and area-efficient 3rd-order continuous-time delta-sigma (CT ΔΣ) modulator for LTE/TD-SCDMA digital receivers. In the proposed modulator, the integrators' coefficients are programmable to meet all LTE and TD-SCDMA signal bandwidths and dynamic range requirements. Moreover, to meet both the high performance and low-cost requirements, the proposed analog-to-digital converter (ADC) adopts: a low-cost excess loop delay compensation method, a non-return-to-zero feedback digital-to-analog converter (DAC) which is clocked by low-noise LC phase lock loop, an on-chip tuning scheme to reduce sensitivity to bandwidth variations, and dynamic element matching 9-level DACs. The CT ΔΣ modulator is designed and fabricated in a 0.13 μm 1-poly 6-metal standard CMOS technology and occupies an active area of 0.20 mm2. For all signal bandwidths of LTE/TD-SCDMA standards, the proposed ADC achieves 70---87 dB dynamic range, and 66---84 dB peak SNDR with 8.4---10.2 mW power consumption under 1.5 V power supply.

A Low Power Class-AB Audio Power Amplifier With Dynamic Transconductance Compensation in 55 nm CMOS Process

This paper presents a Class-AB audio power amplifier with state-of-the-art power efficiency and performance. In this work, the second stage transconductance of the three-stage power amplifier can be dynamically compensated, in order to automatically adjust the amplifier pole according to the operating condition of the output stage. Working with a current sensing module, the proposed dynamic transconductance compensation scheme is more power-efficient to allocate the frequency of non-dominant-pole under a specified stability requirement. A prototype chip is designed and fabricated using 55 nm CMOS process. The measured static current consumption of the core circuit is 0.35 mA with a 1.8 V supply voltage. −85 dB THD+N, 106 dB signal dynamic range and 55 mW output power are verified in silicon under a wide range of load capacitance from 5 pF to 20 nF. Measurement result shows the proposed transconductance compensation technique is effective in both constant voltage supply mode and dynamic supply (Class-G) mode.