High-resolution Mode Research Articles

All-passive transformable optical mapping near-eye display

We present an all-passive, transformable optical mapping (ATOM) near-eye display based on the “human-centric design” principle. By employing a diffractive optical element, a distorted grating, the ATOM display can project different portions of a two-dimensional display screen to various depths, rendering a real three-dimensional image with correct focus cues. Thanks to its all-passive optical mapping architecture, the ATOM display features a reduced form factor and low power consumption. Moreover, the system can readily switch between a real-three-dimensional and a high-resolution two-dimensional display mode, providing task-tailored viewing experience for a variety of VR/AR applications.

Wide Swath and High Resolution Airborne HyperSpectral Imaging System and Flight Validation.

Wide Swath and High Resolution Airborne Pushbroom Hyperspectral Imager (WiSHiRaPHI) is the new-generation airborne hyperspectral imager instrument of China, aimed at acquiring accurate spectral curve of target on the ground with both high spatial resolution and high spectral resolution. The spectral sampling interval of WiSHiRaPHI is 2.4 nm and the spectral resolution is 3.5 nm (FWHM), integrating 256 channels coving from 400 nm to 1000 nm. The instrument has a 40-degree field of view (FOV), 0.125 mrad instantaneous field of view (IFOV) and can work in high spectral resolution mode, high spatial resolution mode and high sensitivity mode for different applications, which can adapt to the Velocity to Height Ratio (VHR) lower than 0.04. The integration has been finished, and several airborne flight validation experiments have been conducted. The results showed the system’s excellent performance and high efficiency.

A 5500-frames/s 85-GOPS/W 3-D Stacked BSI Vision Chip Based on Parallel In-Focal-Plane Acquisition and Processing

This paper presents a 3-D stacked vision chip featuring in-focal-plane read-out tightly coupled with flexible computing architecture for configurable high-speed image analysis. The chip architecture is based on a scalable standalone structure integrating image sensor on the top tier and processing elements (PEs) plus memories in the bottom tier. By using 3-D stacking partitioning, our prototype benefits from backside illuminated pixels sensitivity, a fully parallel communication between image sensor and PEs for low-latency performances, while leaving enough room in the bottom tier to embed advanced computing features. One scalable structure embeds a $16\times 16$ pixel array (or $64\times 64$ pixels in high-resolution mode), associated with an 8-bit single instruction multiple data (SIMD) processor; fabricated in dual 130-nm 1P6M CMOS process. This paper exhibits a 5500 frames/s and 85 giga operations per second (GOPS)/W in low-resolution mode, with large kernels capabilities through eight directions interpixel communication. Multiflow capability is also demonstrated to execute different programs in different areas of the vision chip.

Experimental Modal Analysis of Tumorigenesis and Cancer Metastasis

Traditionally, performing an experimental modal analysis of a building/structure required instrumenting the structure with a spatially distributed array of accelerometers or strain gages. Alternatively, a laser doppler vibrometer would have to be scanned across the structure of interest in a sequential manner to measure structural response. Recently, researchers at LANL developed a technology that combines the theory of structural dynamics with computer vision that provides the capability to characterize structural dynamics at very high spatial density using only an imager. With this newfound success at the macro‐scale, we have exploited this novel technology to a whole new scale‐to studying the basic structure of life itself, the human cell. We hypothesize that this new technology and novel application will provide a significantly better understanding of how stiffness and mass distribution changes in a cell as it undergoes epithelial‐mesenchymal transition, and in identifying its associated EMC biochemical cues, highlight potential therapeutic targets. For the first time it should be possible to measure the high‐resolution mode shapes of cells; given that all cells undergoing cancer metastasis experience a breakdown in the cytoskeleton, this work will enable groundbreaking advances. It is imperative to highlight, that we are only beginning to understand the relationship between biophysical properties of cells and their potential to regulate tumorigenesis and motility. This knowledge could be used to provide verification and validation of finite element models of cellular structure. This work will represent the first time that expertise in experimental structural dynamics will be brought to bear on the problem of characterizing the structural dynamics of cells at high spatial resolution, which is novel and unique on its own. When successful, this new technology could be used to couple the biophysical cues associated with other detrimental human pathologies.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Electrical control of spatial resolution in mixed-dimensional heterostructured photodetectors

Low-dimensional nanomaterials, such as one-dimensional (1D) nanomaterials and layered 2D materials, have exhibited significance for their respective unique electronic and optoelectronic properties. Here we show that a mixed-dimensional heterostructure with building blocks from multiple dimensions will present a synergistic effect on photodetection. A carbon nanotube (CNT)-[Formula: see text]-graphene photodetector is representative on this issue. Its spatial resolution can be electrically switched between high-resolution mode (HRM) and low-resolution mode (LRM) revealed by scanning photocurrent microscopy (SPCM). The reconfigurable spatial resolution can be attributed to the asymmetric geometry and the gate-tunable Fermi levels of these low-dimensional materials. Significantly, an interference fringe with 334 nm in period was successfully discriminated by the device working at HRM, confirming the efficient electrical control. Electrical control of spatial resolution in CNT-[Formula: see text]-graphene devices reveals the potential of the mixed-dimensional architectures in future nanoelectronics and nano-optoelectronics.

Comprehensive analysis of pig feces metabolome by chromatographic techniques coupled to mass spectrometry in high resolution mode: Influence of sample preparation on the identification coverage

Pig feces is an interesting biological sample to be implemented in metabolomics experiments by virtue of the information that can be deduced from the interaction between host and microbiome. However, pig fecal samples have received scant attention, especially in untargeted metabolomic studies. In this research, an analytical strategy was planned to maximize the identification coverage of metabolites found in pig fecal samples. For this purpose, two complementary platforms such as LC–QTOF MS/MS and GC–TOF/MS were used. Concerning sample preparation six extractant solvents with different polarity grade were tested to evaluate the extraction performance and, in the particular case of GC–MS, two derivatization protocols were compared. A total number of 303 compounds by combination of all the extractants and analytical platforms were tentatively identified. The main identified families were amino acids, fatty acids and derivatives, carbohydrates and carboxylic acids. For GC–TOF/MS analysis, the recommended extractant is methanol, while methoxymation was required in the derivatization protocol since this step allows detecting the α-keto acids, which are direct markers of the microbiome status. Concerning LC–QTOF MS/MS analysis, a dual extraction approach with methanol (MeOH) or MeOH/water and ethyl acetate is proposed to enhance the detection of polar and non-polar metabolites.

Chemometrics-assisted optimization of liquid chromatography-quadrupole-time-of-flight mass spectrometry analysis for targeted metabolomics

Mass spectrometry-based metabolomics is characterized by a vast number of variables leading to a great degree of complexity. In this work, we aimed to simplify this process with a stepped chemometric optimization of the both funnel technology (funnel exit DC, FDC; funnel RF LP, FLC; funnel RF HP, FRP) and ion source parameters (Octopolo, Oct; and Fragmentor, Frag) of a quadrupole-time of flight (qTOF) for a human urinary metabolites. The workflow comprised a Box-Behnken experimental design with 47 experiments followed by the identification and quantification of a set of metabolites using high-resolution full-scan MS mode and feature extraction with an inclusion list. Metabolite peak areas were grouped according to abundance (high and low) and modeled by Random Forest regression (variance explained >85%). The full three-level factorial design consisting in 243 experiments was predicted and top 10 solutions for desirability function and those comprising the Pareto front were extracted and investigated. To guarantee the quality of results, we compared the Pareto front solutions with those achieved by standard instrumental parameters suggested by the manufacturer. A set of five solutions were identified that increased the mean peak area by 56–59% and 17%, for high- and low-abundance metabolites, respectively. The optimal parameters were determined to be: FLP, 100 V; FDC, 40 and 30 V; Frag, 275 and 400 V; and Oct, 600 and 800 V. The methodology applied throughout this work represents a flexible strategy to optimize instrumental parameters and exploit the performance of a qTOF MS detector.

A high-resolution ICP-MS method for the determination of 38 inorganic elements in human whole blood, urine, hair and tissues after microwave digestion

Inductively coupled plasma-mass spectrometry (ICP-MS) is currently the reference method for the determination of inorganic elements, and has many applications in healthcare and the environmental field. The objective of the present study was to develop and validate a high-resolution ICP-MS method for the simultaneous quantification of 38 elements in samples of human whole blood, urine, hair and tissues after microwave mineralization. The samples were incubated with nitric acid, hydrogen peroxide and internal standards prior to microwave mineralization for 25 min. The analysis was performed with an Element XR ICP-MS and validated using commercial reference standards (whole blood, urine, and hair) and in-house quality control samples. The 38 elements were detected in low-, medium- or high-resolution mode, depending on interferences and sensitivity. The lower and upper limits of quantification were adjusted for each element. The method was linear for all elements (correlation coefficient >0.996), and the inter- and intraday precision values (coefficient of variation) were below 15%. Samples from a clinical trial were used to confirm the high-resolution ICP-MS method’s suitability for the assessment of patient samples.

Diagnostic accuracy of cone beam computed tomography with different resolution settings for external root resorption

To evaluate the diagnostic accuracy of cone beam computed tomography (CBCT) with different resolution settings in detecting the simulated external root resorption defects. External root resorption defects were simulated in 51 human single rooted premolar teeth. Cavities simulating root resorption defects of 1 mm in diameter and 0.1 mm, 0.2 mm, and 0.3 mm in depth were drilled in the cervical, middle and apical thirds of lingual surfaces of the teeth. In addition to the 51 locations as controls, a total of 102 cavities were obtained in the present study. Specimens were placed in a human dry mandible and scanned by ProMax 3D and DCT PRO CBCT with different resolution settings, respectively. The three-dimensional CBCT images were evaluated by two experienced observers. The data were analyzed with receiver operating characteristics (ROC) analysis. ROC curves were generated and the area under ROC curve (Az) was employed to express the diagnostic accuracy. The diagnostic accuracy (Az value) of ProMax 3D CBCT with high, normal and low resolution settings were 0.867, 0.703 and 0.665 (P < 0.05), respectively. Defects with depths of 0.2 mm and 0.3 mm were easier to be detected than those with depths of 0.1 mm (P < 0.05). The images obtained by high resolution mode scanning had obvious advantages in detecting smaller defects (depth 0.1 mm and 0.2 mm). The DCT PRO CBCT provided 4 resolution settings including normal quality + normal resolution, normal quality + high resolution, high quality + normal resolution and high quality + high resolution. The Az values for those 4 resolution settings were 0.527, 0.725, 0.743, and 0.794 (P < 0.05), respectively. Similar to ProMax 3D CBCT, the scanning mode with high resolution played a better role in detecting the defects with depth of 0.1 mm. Except for the scanning setting mode with normal quality + normal resolution, the other three modes could well be evaluated for the defects with depth of 0.2 mm and 0.3 mm. It is concluded that the diagnostic ability for external root resorption of CBCT could be affected by resolution settings. Computer-aid imaging method can improve the CBCT diagnostic accuracy for external root resorption without increasing the radiation dose level during CBCT scanning.

Bayesian operational modal analysis and assessment of a full-scale coupled structural system using the Bayes-Mode-ID method

This paper presents a structural assessment project for a construction training center in Hong Kong. The training center consists of coupled main and complementary buildings. Due to the vigorous activities in the training center, the objectives of the project include conducting operational modal analysis (OMA) of the buildings to assess their structural performance and the coupling of vibrations between the two buildings. OMA is conducted using Bayes-Mode-ID recently developed by the authors, which is an efficient Bayesian modal-component-sampling system identification method for field testing of civil engineering structures under ambient vibrations. Implementation issues for Bayes-Mode-ID are discussed in detail for the full-scale coupled structural system. Due to the large number of measurement points (high resolution mode shapes are desired for understanding the coupling behavior of the system) and limited number of sensors, the measurements were divided into 21 setups in order to properly characterize the dynamics of the building. Each setup covered one portion of the training center and the partial mode shapes from different setups were assembled to provide the global mode shapes. By following a Bayesian approach, not only the most probable values (MPVs) of the modal parameters (modal frequencies, modal damping ratios and mode shapes) but also their associated uncertainties can be obtained. The identified modal parameters reveal interesting dynamic behaviors of the coupled-building and they will be helpful for structural assessment and structural health monitoring (SHM) of the training center in the future.

Dual-mode phase-shifting interferometry based on iterative algorithms

Iterative algorithms are useful for retrieving wavefront phase from vibration disturbed interferograms for phase-shifting interferometry (PSI). But the dependence of convergence on the initial value deviation from the exact value impairs their application in severe vibration. In this paper, performance investigation of a representative iterative algorithm indicates that a higher frame rate of the camera, with matched phase shift, helps in enhancing the success probability of convergence. However, the camera frame rate is limited by its transmission speed and could not be increased easily. To improve the convergence of iterative algorithms, a dual-mode (DM) PSI is proposed that utilises the binning function of cameras. In DMPSI, two modes, high-speed and high-resolution modes, work consecutively by switching the camera binning function and two series of interferograms are collected respectively. The wavefront phase could be accurately estimated from high-speed interferograms and then is input to the iterative calculation with high-resolution interferograms as the initial value, and a wavefront phase with high-resolution is achieved ultimately. DMPSI combines the advantages of two complementary modes of cameras to reconstruct an accurate and high-resolution wavefront. Both simulations and a practical measurement verify the enhancement of vibration resistance of iterative algorithms. DMPSI is easy to implement with low cost and good compatibility, predicating a reliable solution for optical wavefront measurement in the severe vibration.

Positive ion SIMS-SSAMS for trace analysis of materials

By using a single-stage accelerator mass spectrometer (SSAMS) as a detector for a secondary ion mass spectrometry (SIMS) instrument, spatially resolved trace analysis of elements and isotopes in solid materials is significantly improved. This is especially true for masses greater than ∼90 u, where a mass resolving power in excess of 10,000 is generally needed to separate abundant molecular isobars from atomic ions of interest, particularly when the atomic species are present in trace quantities. Prior techniques using SIMS in high-resolution mode can suffer from residual molecular interferences that effect detection limits and isotope analysis precision. The 300 kV SSAMS at the U.S. Naval Research Laboratory typically measures +1 ions up to mass 300 u, as they are more abundant for most elements. Additionally, there can be no molecule fragments in a lower charge state at the same m/q and E/q. Interferences from higher charge states either injected into the SSAMS or generated by the stripper tube are limited to mimicking masses below ∼120 u. Molecule fragments can also be chosen for analysis, when a molecular ion is more abundant than an atomic one. Electrostatic peak switching through the SIMS and SSAMS magnets enables rapid cycling up to ±6.5% about a central mass during a depth profile measurement. For typical operating conditions using Ar gas in the stripper tube, molecular ions are reduced by 4–6 orders of magnitude while better than 20% of desired ions are transmitted. These numbers depend on gas thickness in the stripper, mass of the ion, and molecule involved. Cross sections for molecule destruction and ion transmission, and charge state +1 ion yields are described for a number of different stripper gases and ions. Example trace analysis measurements demonstrate the instrument’s capabilities.

Electrochemical Oxidation Pathways of Hydroxycoumarins on Carbon Electrodes Examined by LSCV and LC–MS/MS

It is reported the voltammetric behavior and the identification of the oxidation products of four different hydroxycoumarins, namely, 3-, 4-, 6- and 7-hydroxycoumarin (3HC, 4HC, 6HC and 7HC), on carbon electrodes by performing bulk electrolyses in buffered solutions. LC–MS/MS in high resolution mode is used for the product identification. It was found that the voltammetric behaviors of the four compounds are quite different, as well as the corresponding oxidation products. For 3HC the end product was 2-hydroxymandelic acid [2-hydroxy-2-(2-hydroxyphenyl)acetic acid]: for 4HC, salicylic acid [2-hydroxybenzoic acid]; for 6HC, 2H-1-benzopyran-2,6(8aH)-dione and for 7HC no low-molecular weight products were identified. Based on these products and on the voltammetric results, the overall oxidation pathways are formulated as four-electron processes for 3HC and 4HC, and two-electron processes for 6HC. 7HC oxidation is proposed to be an electropolymerization reaction.

A Device for Recording TV Images with High Intensity Resolution and Stroboscopic Recording Mode

A device for providing registration of grayscaled images that are formed by an analog television camera with transformation of the intensities of discrete spatial samples of an image into a 10-bit digital code is described. A method for visualizing the images with a high intensity resolution on the screen of a typical monitor, which provides rendering of more than 1000 gray tones, is proposed and its practicality is discussed. The method of implementing the stroboscopic mode of recording physical processes, which are initiated by the action of electrical pulses of the signal source, is described and the results of its application to the analysis of thermal processes in semiconductor laser diode arrays are presented.

Detection of RHD zygosity in China: using Syber Green Ⅰ real-time polymerase chain reaction based on high-resolution melting curve analysis

Due to relatively higher mutation frequencies in Chinese individuals with the RHD-negative phenotype[25% for 1227 G>A RHD elution and 5% for RHD1-RHCE(2-9)-RHD10], Rhesus box analysis is rarely used in China. Here, quantitative real-time polymerase chain reaction (qPCR) with a high-resolution melting curve mode and a matrix mix containing Syber Green Ⅰ were used to sequence specific primers of 1227 G>A and RHD exons 1, 5, and 10 in two families, consisting of two parents and two children per family (n = 8). The samples with RHD gene dele- tion homozygous/heterozygous, 1227 G>A heterozygous with RHD gene deletion and normal RHD, normal RHD homozygous/heterozygous, and RHD1-RHCE(2-9)-RHD10 homozygous/heterozygous status were all included. All samples were screened using RHD exon genotyping, Sanger sequencing, and Rhesus box analysis. DNA sample quality was maintained at 68~72 ng/μL, and OD_260/280 at 1.7~1.9. The Tm ratio of RHD exon 1 (87 ℃ ) to internal control (77℃ ) was 2.49~2.67 and 2.09~2.35 in subjects with RHD exon 1 homozygous and heterozygous, respectively; the Tm ratio of RHD exon 10 (81℃ ) to internal control (77℃ ) was 5.01~6.11 and 3.34~4.31 in subjects with RHD exon 10 homozygous and heterozygous, respectively; the Tm ratio of RHD exon 5 (83℃ ) to internal control (77℃ ) was 3.98~4.75, 3.02~3.45, and 0.03 in subjects with RHD exon 5 homozygous, heterozygous, and deletion homozygous, respectively; the Tm ratio of 1227A (87℃ ) to internal control (77℃ ) was 1.11, 0.51, and <0.03 in subjects with 1227A heterozygous, 1227A homozygous (exon 9 deletion), and wild type, respectively. The results suggest that using the primers of Tm ratio in comparison with an internal control is an effective way to detect RHD gene deletion or RHD-RHCE hybrid variant allele carrier. The method can also be used to calculate the mother-newborn RHD phenotype proportion and assist pedigree analysis.

Evaluation of a preclinical photon-counting CT prototype for pulmonary imaging

The purpose of this study was to investigate a preclinical spectral photon-counting CT (SPCCT) prototype compared to conventional CT for pulmonary imaging. A custom-made lung phantom, including nodules of different sizes and shapes, was scanned with a preclinical SPCCT and a conventional CT in standard and high-resolution (HR-CT) mode. Volume estimation was evaluated by linear regression. Shape similarity was evaluated with the Dice similarity coefficient. Spatial resolution was investigated via MTF for each imaging system. In-vivo rabbit lung images from the SPCCT system were subjectively reviewed. Evaluating the volume estimation, linear regression showed best results for the SPCCT compared to CT and HR-CT with a root mean squared error of 21.3 mm3, 28.5 mm3 and 26.4 mm3 for SPCCT, CT and HR-CT, respectively. The Dice similarity coefficient was superior for SPCCT throughout nodule shapes and all nodule sizes (mean, SPCCT: 0.90; CT: 0.85; HR-CT: 0.85). 10% MTF improved from 10.1 LP/cm for HR-CT to 21.7 LP/cm for SPCCT. Visual investigation of small pulmonary structures was superior for SPCCT in the animal study. In conclusion, the SPCCT prototype has the potential to improve the assessment of lung structures due to higher resolution compared to conventional CT.

Evaluation of convection-permitting WRF CONUS simulation on the relationship between soil moisture and heatwaves

Soil moisture plays an important role in modulating regional climate from sub-seasonal to seasonal timescales. Particularly important, soil moisture deficits can amplify summer heatwaves (HWs) through soil moisture-temperature feedback which has critical impacts on society, economy and human health. In this study, we evaluate decade-long convection-permitting Weather Research and Forecast (WRF) model simulations over the contiguous US on simulating heatwaves and their relationship with antecedent soil moisture using a dense observational network. We showed that the WRF model is capable of capturing the spatial patten of temperature threshold to define HWs, though the simulation shows a warm bias in the Midwest and cold bias in western mountainous regions. Two HW indices, based on frequency (HWF) and magnitude (HWM), are evaluated. Significant anti-correlations between antecedent soil moisture and both HW indices have been found in most parts of the domain except the South Pacific Coast. A detailed study has been conducted for the Midwest and South Great Plains regions, where two heatwaves had occurred in the last decade. In both regions, the high quantile of the HWF distribution shows a strong dependence on antecedent soil moisture: drier soil leads to much larger increase on the upper quantile of HWF than it does on the lower quantile. Soil moisture effects on the higher end of HWM are not as strong as on the lower end: wetter antecedent soil corresponds to a larger decrease on the lower quantile of HWM. WRF captures the heterogeneous responses to dry soil on HWF distribution in both regions, but overestimates these HWM responses in the Midwest and underestimates them in the South Great Plains. Our results show confidence in WRF’s ability to simulate HW characteristics and the impacts of antecedent soil moisture on HWs. These are also important implications for using high-resolution convection-permitting mode to study the coupling between land and atmosphere.

A multipurpose instrument for time-resolved ultra-small-angle and coherent X-ray scattering.

This article presents the main technical features and performance of the upgraded beamline ID02 at the ESRF. The beamline combines different small-angle X-ray scattering techniques in one unique instrument, enabling static and kinetic investigations from ångström to micrometre size scales and time resolution down to the sub-millisecond range. The main component of the instrument is an evacuated detector tube of length 34 m and diameter 2 m. Several different detectors are housed inside a motorized wagon that travels along a rail system, allowing an automated change of the sample-detector distance from about 1 to 31 m as well as selection of the desired detector. For optional combined wide-angle scattering measurements, a wide-angle detector is installed at the entrance cone of the tube. A scattering vector (of magnitude q) range of 0.002 ≤ q ≤ 50 nm-1 is covered with two sample-detector distances and a single-beam setting for an X-ray wavelength of 1 Å. In the high-resolution mode, two-dimensional ultra-small-angle X-ray scattering patterns down to q < 0.001 nm-1 can be recorded, and the resulting one-dimensional profiles have superior quality as compared to those measured with an optimized Bonse-Hart instrument. In the highest-resolution mode, the beam is nearly coherent, thereby permitting multispeckle ultra-small-angle X-ray photon correlation spectroscopy measurements. The main applications of the instrument include the elucidation of static and transient hierarchical structures, and nonequilibrium dynamics in soft matter and biophysical systems.

Measurement of apparent ion temperature using the magnetic recoil spectrometer at the OMEGA laser facility.

The Magnetic Recoil neutron Spectrometer (MRS) at the OMEGA laser facility has been routinely used to measure deuterium-tritium (DT) yield and areal density in cryogenically layered implosions since 2008. Recently, operation of the OMEGA MRS in higher-resolution mode with a new smaller, thinner (4 cm2, 57 μm thick) CD2 conversion foil has also enabled inference of the apparent DT ion temperature (T ion) from MRS data. MRS-inferred T ion compares well with T ion as measured using neutron time-of-flight spectrometers, which is important as it demonstrates good understanding of the very different systematics associated with the two independent measurements. The MRS resolution in this configuration, ΔE MRS = 0.91 MeV FWHM, is still higher than that required for a high-precision T ion measurement. We show how fielding a smaller foil closer to the target chamber center and redesigning the MRS detector array could bring the resolution to ΔE MRS = 0.45 MeV, reducing the systematic T ion uncertainty by more than a factor of 4.

A 100-MS/s–5-GS/s, 13–5-bit Nyquist-Rate Reconfigurable Time-Domain ADC

This paper presents a 65-nm CMOS Nyquist-rate reconfigurable time-based analog-to-digital converter (ADC). The time-domain nature of the ADC allows for efficient hardware reuse and a wide range of reconfigurability. The ADC employs a reconfigurable time-to-digital converter (TDC) that can be configured as a high-resolution 1-ps correlated double sampling SAR-TDC for the high-resolution modes or as a $4\times $ asynchronous time-interleaved flash-TDC for the high sampling rate modes. The Nyquist-rate ADC supports continuous sampling rate variations from 100 MS/s to 5 GS/s providing 13–5-bit resolution with exponential power scaling from 8.4 to 22.3 mW, respectively. A programmable highly linear 1-bit folded voltage-controlled oscillator is employed to provide the appropriate tuning characteristics for different sampling rate modes with high linearity. The ADC linearity is further enhanced using foreground digital calibration achieving figure-of-merit ranging from 14.6 to 196 fJ/conv.