Synchronous Sampling Research Articles

Fault Section Identification for Hybrid Transmission Lines Considering the Weak-Feed Characteristics of Floating Photovoltaic Power Plant Inverters

The overhead line (OHL)–cable hybrid transmission line, which connects floating photovoltaic (PV) power plants, needs to be considered regarding whether to block reclosing operations or not. However, due to the weak-feed characteristics of PV inverters, existing methods are difficult to apply in this scenario. This paper proposes a criterion for fault section identification in the transmission lines of floating PV power plants based on traveling wave power and the zero-sequence impedance angle. Firstly, the fault current characteristics of photovoltaic inverters under dual-vector control are analyzed, and the applicability of the sequence component impedance directional criterion in this scenario is discussed. Then, the transmission, refraction, and reflection processes of traveling waves in OHL–cable hybrid lines are analyzed, and a traveling wave energy criterion is designed to determine the fault section. Finally, based on the scope of application of the zero-sequence impedance angle and traveling wave energy criterion, a fault section identification method for the hybrid lines of floating PV power plants is established. A deployment method for the proposed method, based on feeder terminal units (FTUs) at the connection points between the OHL and cable is proposed. This method identifies fault sections through traveling waves and zero-sequence impedance angles, which are unaffected by PV week feed characteristics, can be applied to all the AC fault types, and do not rely on multi-terminal synchronous sampling. The proposed method is verified on a 1MW PV system built in the PSCAD.

Capacitor Voltage Feedback Active Damping With Reduced Computation Delay for Improving Voltage Control Performance of LC‐Type Grid‐Forming Inverter

ABSTRACTIn low‐voltage applications using low‐Q LC filters, alias‐free capacitor voltage acquisition can be achieved, but synchronous capacitor voltage sampling under high‐Q filters used in high‐voltage applications in grid‐forming converters causes some degree of distortion and results in degradation of the power supply quality. And the inherent 1.5 sampling periods that delay in this approach limit the control bandwidth, reduce the stability region, and result in an inadequate time domain response. Despite these shortcomings, this approach is widely accepted in practice. The conclusion of this paper is that shifting the capacitor voltage sampling instant to 2 µs before the pulse width modulation (PWM) reference voltage update results in almost the same distortion as synchronous sampling. However, it can improve the dynamic performance of the system. A distortion‐acceptable univariate feedback voltage dual‐loop active damping control topology with much reduced computational delay is proposed, which is based on an internal active damping loop using a discrete lead compensator and a proportional resonance controller in the external voltage loop.

Clinical Value of Liquid Biopsy in Patients with FGFR2 Fusion-Positive Cholangiocarcinoma During Targeted Therapy.

FGFR2 fusions occur in 10% to 15% of patients with intrahepatic cholangiocarcinoma (iCCA), potentially benefiting from FGFR inhibitors (FGFRi). We aimed to assess the feasibility of detecting FGFR2 fusions in plasma and explore plasma biomarkers for managing FGFRi treatment. We conducted a retrospective study in 18 patients with iCCA and known FGFR2 fusions previously identified in tissue samples from prior FGFRi treatment. Both tissue and synchronous plasma samples were analyzed using a custom hybrid capture gene panel with next-generation sequencing (VHIO-iCCA panel) and validated against commercial vendor results. Longitudinal plasma analysis during FGFRi was performed. Subsequently, we explored the correlation between plasma biomarkers, liver enzymes, tumor volume, and clinical outcomes. Sixteen patients (88.9%) were positive for FGFR2 fusion events in plasma. Remarkably, the analysis of plasma suggests that lower levels of ctDNA are linked to clinical benefits from targeted therapy and result in improved progression-free survival and overall survival. Higher concentrations of cell-free DNA before FGFRi treatment were linked to worse overall survival, correlating with impaired liver function and indicating compromised cell-free DNA removal by the liver. Additionally, increased ctDNA or the emergence of resistance mutations allowed earlier detection of disease progression compared with standard radiologic imaging methods. VHIO-iCCA demonstrated accurate detection of FGFR2 fusions in plasma. The integration of information from various plasma biomarkers holds the potential to predict clinical outcomes and identify treatment failure prior to radiologic progression, offering valuable guidance for the clinical management of patients with iCCA.

Comparative study on the quality of wild and ecologically farmed large yellow croaker through on-site synchronous sampling from the Nanji Archipelago in the East China Sea

With consumers demanding higher quality in fish products, ecologically farmed fish are increasingly favored due to their quality being close to that of wild fish. However, the differences between the ecologically farmed and wild fish remain largely unclear. In the present study, the wild and ecologically farmed large yellow croakers of the same size were captured simultaneously from the same marine area around Nanji islands (27.479°E, 121.052°N). Then, synchronous tests were conducted to evaluate quality to clarify the key quality parameters that differentiate between the wild and farmed fish. We obtained 49 quality parameters after orthogonal partial least squares discriminant analysis (OPLS-DA) with variable importance in projection (VIP) scores >1 and p < 0.05 using 307 indicators related to 121 length ratios, 4 body color indicators, 5 muscle fiber characteristic indicators, 87 nutrition quality parameters, 40 taste parameters, and 50 volatile compounds. Compared to the farmed fish, the wild fish exhibited a more yellow skin color, higher levels of carotenoids, and a more streamlined conical shape. Changes in histology and ultrastructure of muscle fibers were noted, including increased muscle fiber density and the ratio of fiber area to gap, as well as reduced I band width, observed in the wild fish. The wild fish had high nutritional value of fatty acids and minerals and low nutritional value of amino acids, as reflected by higher levels of C22: 6n3 (DHA), Σn-3 PUFA (polyunsaturated fatty acids), Σn-3/Σn-6 PUFA, Na (sodium), K (potassium), Fe (iron), and Se (selenium), and lower values of ΣMUFA (monosaturated fatty acids), Σn-6 PUFA, TI (thrombogenic index), amino acid and chemistry scores of isoleucine, ΣEAA/ΣTAA (essential amino acid/ total amino acid), and ΣTAA/ΣNEAA (total amino acid/non-essential amino acid) in the muscles of the wild fish. The wild fish muscle showed high levels of hydrolyzed glycine and proline and free methionine, and low levels of free glycine and proline, indicating a propensity for collagen synthesis. Despite significant differences in the contents of fourteen flavor substances of free amino acids, 5′-nucleotides, and volatile compounds, their concentrations were notably below the corresponding threshold and contributed minimally to flavor, suggesting that the wild and farmed fish shared similar flavor characteristics. In summary, this study reveals the quality differences between ecologically farmed and wild large yellow croaker based on on-site synchronous sampling, providing a theoretical foundation for further enhancing the quality of this species.

A novel meta‐learning network for partial discharge source localization in gas‐insulated switchgear via digital twin

AbstractDue to the requirement for highly precise synchronous sampling and the substantial reliance on time difference calculations, the current partial discharge (PD) localization based on the time difference of arrival is only applicable in certain situations. As digital twin technology has advanced, it is possible to employ virtual models to support gas‐insulated switchgear (GIS) PD localization. To do this, we propose a meta‐learning (ML) network with the aid of digital twin for actual GIS PD localization. Firstly, a GIS digital twin model was established to acquire an auxiliary simulated sample library. Then, a temporal convolutional network is established to extract the discriminable features, effectively obtain the time dependence between features, and improve the accuracy of localization. Next, ML is adopted to quickly learn meta‐knowledge that can be applied across tasks, and the model's sensitivity to task changes is improved. Finally, the model is fine‐tuned through a limited number of samples from the target task, and high precise PD localization is achieved. The experimental results demonstrate that the ML has an average localization error of only 9.25 cm and a probability density rose to 93% within 20 cm, which is clearly superior to previous methods.

Research autopsy programmes in oncology: shared experience from 14 centres across the world.

While there is a great clinical need to understand the biology of metastatic cancer in order to treat it more effectively, research is hampered by limited sample availability. Research autopsy programmes can crucially advance the field through synchronous, extensive, and high-volume sample collection. However, it remains an underused strategy in translational research. Via an extensive questionnaire, we collected information on the study design, enrolment strategy, study conduct, sample and data management, and challenges and opportunities of research autopsy programmes in oncology worldwide. Fourteen programmes participated in this study. Eight programmes operated 24 h/7 days, resulting in a lower median postmortem interval (time between death and start of the autopsy, 4 h) compared with those operating during working hours (9 h). Most programmes (n = 10) succeeded in collecting all samples within a median of 12 h after death. A large number of tumour sites were sampled during each autopsy (median 15.5 per patient). The median number of samples collected per patient was 58, including different processing methods for tumour samples but also non-tumour tissues and liquid biopsies. Unique biological insights derived from these samples included metastatic progression, treatment resistance, disease heterogeneity, tumour dormancy, interactions with the tumour micro-environment, and tumour representation in liquid biopsies. Tumour patient-derived xenograft (PDX) or organoid (PDO) models were additionally established, allowing for drug discovery and treatment sensitivity assays. Apart from the opportunities and achievements, we also present the challenges related with postmortem sample collections and strategies to overcome them, based on the shared experience of these 14 programmes. Through this work, we hope to increase the transparency of postmortem tissue donation, to encourage and aid the creation of new programmes, and to foster collaborations on these unique sample collections. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Morphology of the Skulls from the Burials in the Village of Zalutske (tract Staikyn Verkh), Sumy Region (the 18th – 19th Centuries)

The focus of this article is on the publication of craniological findings from a cemetery located near Zalutske village (tract Staikyn Verkh), Romny district. Materials and methods: Anthropological materials dating from the 18–19th cent. primarily consist of well-preserved human skulls. The collection comprises 8 items, including 5 male and 3 female skulls. Measurements were conducted following a comprehensive craniometric program based on R. Martin’s standard technique, with numbered features indicated accordingly. Software for multidimensional analysis was developed by B. and A. Kozintsev in 1991. The primary objective of this research is to present new craniological data to the scientific community, providing a general description of local inhabitants in comparison to neighboring ethnic groups in Ukraine and Eastern Europe. The study aims to determine the distance between individual series from the 14–19th cent. through multidimensional canonical and cluster analysis, seeking to position local peasants within the system of craniological types in Eastern Europe and the pheno-geographic anthropological zones of Ukraine. Novelty in research lies in the submission of craniometric measurements and characteristics from skulls of the 18–19th cent. in a craniological series from Zalutske village, a first-time occurrence. Results show the creation of a male series from Zalutske village of the 18–19th cent., consisting of 5 skulls. The group is characterized as moderately brachycranial based on the average craniometric values. Upon comparing the studied male group from the 18–19th cent. with synchronous series and samples from the 16th to 19th centuries in Eastern, Central, and Western Europe using multidimensional canonical and cluster analysis, partial similarity to the Transcarpathian urban group of Uzhhorod was observed.

Improved Synchronous Sampling and Its Application in High-Speed Railway Bearing Damage Detection

Synchronous analysis is one of the most effective and practical techniques in rotating machinery diagnostics, especially in cases with variable speed operations. A modern analog-to-digital convertor (ADC) usually digitizes an analog signal to an equal time interval data series. Synchronous resampling converts the data series from an equal time interval data series to an equal shaft rotation angle interval data series. This conversion is usually achieved in the digital domain with the aid of shaft speed information, through either direct measurement or identification from a measured vibration signal, which is a time-consuming process. In order to improve the computational efficiency as well as the data processing accuracy, in this paper, a fast synchronous time-point calculation method based on an inverse function interpolation procedure is proposed. By identifying the inverse function of the instantaneous phase with respect to time, the calculation process of synchronous time points is optimized, which results in improved calculation efficiency and accuracy. These advantages are demonstrated by numerical simulations as well as experimental verifications. The numerical simulation results show that the proposed method can improve calculation speed by about five times. The synchronous analysis based on the proposed method was applied to a bearing fault detection in a high-speed rail carriage, which demonstrated the advantages of the proposed algorithm in improving the signal-to-noise ratio (SNR) for bearing damage feature extraction.

Humification levels of dissolved organic matter in the eastern plain lakes of China based on long-term satellite observations

Under the influence of intensive human activities and global climate change, the sources and compositions of dissolved organic matter (DOM) in the eastern plain lake (EPL) region in China have fluctuated sharply. It has been successfully proven that the humification index (HIX), which can be derived from three-dimensional excitation-emission matrix fluorescence spectroscopy, can be an effective proxy for the sources and compositions of DOM. Therefore, combined with remote sensing technology, the sources and compositions of DOM can be tracked on a large scale by associating the HIX with optically active components. Here, we proposed a novel HIX remote sensing retrieval (IRHIX) model suitable for Landsat series sensors based on the comprehensive analysis of the covariation mechanism between HIX and optically active components in different water types. The validation results showed that the model runs well on the independent validation dataset and the satellite-ground synchronous sampling dataset, with an uncertainty ranging from 30.85 % to 36.92 % (average ± standard deviation = 33.6 % ± 3.07 %). The image-derived HIX revealed substantial spatiotemporal variations in the sources and compositions of DOM in 474 lakes in the EPL during 1986–2021. Subsequently, we obtained three long-term change modes of the HIX trend, namely, significant decline, gentle change, and significant rise, accounting for 74.68 %, 17.09 %, and 8.23 % of the lake number, respectively. The driving factor analysis showed that human activities had the most extensive influence on the DOM humification level. In addition, we also found that the HIX increased slightly with increasing lake area (R2 = 0.07, P < 0.05) or significantly with decreasing trophic state (R2 = 0.83, P < 0.05). Our results provide a new exploration for the effective acquisition of long-term dynamic information about the sources and compositions of DOM in inland lakes and provide important support for lake water quality management and restoration.

Research on the fault diagnosis method of AC power supply in substations based on a synchronous digital sampling technology

In order to improve the accuracy and efficiency of AC power supply fault diagnosis in substations, a fault diagnosis method of AC power supply in substations based on synchronous digital sampling technology is proposed and designed in this study. Based on the IEC 61850-9-2 communication protocol, the same sampling of the status data of the substation AC power supply is realized first. Then, in order to improve the fault diagnosis effect, the data is pre-processed such as de-noising and de-redundancy. Finally, the substation AC power supply fault diagnosis is carried out based on Dempster/Shafer (D-S). The experimental results show that for different types of faults, the diagnosis accuracy of the proposed method is higher than 95.5%, and the diagnosis time is less than 1.31 ms.

Modeling Method of Multiplexed Sampling Electrical Parameter Characteristics Based on AIOT Sensing Module

Abstract In order to further reduce the errors arising in synchronous sampling, this paper designs a multi-channel hybrid sampling electrical parametric feature modeling method based on an AIOT sensing module in the process of design. The AIOT sensing module is used to process the received RF signals using a transconductance amplifier to improve the digitization and reconfigurability of the RF front-end circuit. The signal is transformed and calculated using the Fast Fourier Transform to obtain electrical parameters such as the amplitude of each harmonic and the power factor. The results show that the variation amplitude of the window function of the design method in this paper is generally maintained between -1.5 and 1.5, the amplitude accuracy of the active power rate is within 3.17555%, and the relative error accuracy is within 0.000951%. It can be seen that the AIOT-based sensing module can significantly improve the calculation accuracy of electrical parameters and can be applied to the process of sampling digital measurements of other power signal characteristics.

A real-time dynamic range expansion approach of multi-channel sampling system

Dynamic range (DR) is one of the most critical factors for evaluating a signal processing system. It is limited by all electronic components that signal passes through in the circuit, including the amplifier, analog-to-digital converter and etc. Based on the signal acquisition structure of synchronous sampling with multiple conditioning channels, this paper proposed a method to expand the DR of the system. The proposed method involves the iterative algorithm to calculate the gain and offset between different channels, the threshold voltage setting principles of channel switching, and the data combination approach. More importantly, it can easily be applied in programmable logic gate array in the real-time system. On the basis of ensuring system sensitivity, the input voltage range is increased by combining data from different channels, thereby the DR of the system is increased. The experimental results in the sampling board of the vibration and audio signal analyzer show that the method we discussed in this article has a significant effect on DR expansion in the sampling system.

A SAR ADC for multichannel synchronous signal acquisition

A synchronous sampling multichannel ADC is proposed to sample several signals at the same time and digitize the sampled signals in sequence. Instead of using multiple ADCs or multiple samplers, a modified SAR ADC with multiple capacitive DACs is applied to largely save area and reduce gain and offset mismatches between channels. A common-mode voltage resampling technique is proposed to reduce crosstalk errors between the multiple input signals below the ADC noise floor. To verify the ADC structure, a 10-bit 4-channel SAR ADC has been prototyped and implemented with a 180-nm CMOS technology. The ADC area is 0.325 mm2 (without PAD). At the sampling frequency of 250 kHz per channel, it uses 62 μW to achieve 9.38 ENOB for four input signals. The resolutions of the four channels are mainly limited by the DAC performances.

Tachometer-Less Synchronous Sampling for Large Speed Fluctuations and Its Application in the Monitoring of Wind Turbine Drive Train Condition

Accurate shaft speed extraction is crucial for synchronous sampling in the fault diagnosis of wind turbines. However, traditional narrow-bandpass filtering techniques face limitations when dealing with large fluctuations in rotational speed, hindering the accurate construction of an instantaneous phase for synchronous resampling of a shaft. To overcome this, we propose a tachometer-less synchronous sampling based on Scaling-Basis Chirplet Transform, tailored to a wind turbine’s structure and operating conditions. The algorithm generates a time–frequency representation of the vibration response, revealing time-varying characteristics even under large speed fluctuations. Using maximum tracking on the time–frequency spectrum, we extract instantaneous speed and compare its accuracy with tachometer-acquired results. The instantaneous phase is obtained through numerical integration, and vibration data are resampled synchronously using inverse function interpolation in the digital domain. Numerical simulations and practical cases of wind turbines demonstrate the effectiveness and the engineering applicability of our methodology.

Research on absolute ranging technology of resampling phase comparison method based on FMCW

Abstract As an advanced optical precision ranging method, FMCW (frequency-modulated continuous-wave) laser interferometric ranging technology can achieve a large-scale and high-precision absolute distance measurement, so it has high research and application value in the field of coordinate measurement in large space. How to improve the resolution and stability of laser interferometry is a research difficulty in this technology. Based on FMCW laser interferometry relative distance technology, a method for achieving absolute distance measurement through phase comparison after repeated sampling is proposed. Using the FMCW laser distance measuring system, two interference optical paths of measuring interferometer and auxiliary interferometer are constructed, respectively. Synchronous sampling is performed on two interference signals, and the phase ratio of the two interference signals is obtained through the extracted frequency information. The optical path difference of the unknown measurement interferometer is derived from the known auxiliary interferometer information. This method uses a triangular wave modulation laser to reduce the influence of Doppler frequency shift and eliminate quantization errors. By using the fixed-point repeated sampling, the optical path difference information is quickly extracted, and the nonlinear error of laser interference frequency modulation is effectively reduced.

Improving Worst-case TSN Communication Times of Large Sensor Data Samples by Exploiting Synchronization

Higher levels of automated driving also require a more sophisticated environmental perception. Therefore, an increasing number of sensors transmit their data samples as frame bursts to other applications for further processing. As a vehicle has to react to its environment in time, such data is subject to safety-critical latency constraints. To keep up with the resulting data rates, there is an ongoing transition to a Time-Sensitive Networking (TSN)-based communication backbone. However, the use of TSN-related industry standards does not match the automotive requirements of large timely sensor data transmission, nor it offers benefits on time-critical transmissions of single control data packets. By using the full data rate of prioritized IEEE 802.1Q Ethernet, giving time guarantees on large data samples is possible, but with strongly degraded results due to data collision. Resolving such collisions with time-aware shaping comes with significant overhead. Hence, rather than optimizing the parameters of the existing protocol, we propose a system design that synchronizes the transmission times of sensor data samples. This limits network protocol complexity and hardware requirements by avoiding tight time synchronization and time-aware shaping. We demonstrate that individual sensor data samples are transmitted without significant interference, exclusively at full Ethernet data rate. We provide a synchronous event model together with a straightforward response time analysis for synchronous multi-frame sample transmissions. The results show that worst-case latencies of such sample communication, in contrast to non-synchronized approaches, are close to their theoretical minimum as well as to simulative results while keeping the overall network utilization high.

Asynchronous Sampling-Based Hybrid Equalizer

An equalizer architecture based on asynchronous sampling is described. The circuit implementation is a hybrid feed-forward equalizer (FFE) using three digital postcursor taps realized via level-crossing samplers (LCSs) and inverter-based delays. Utilizing a current mode logic (CML)-based summer stage, an analog main tap and digital postcursor taps are combined into an inductively tuned resistor load. With a 0.67-mV-rms simulated output-referred noise, the FFE has better noise performance than a conventional continuous-time linear equalizer (CTLE) and a slicer/latch-based decision feedback equalizer (DFE) circuit. Moreover, it exhibits very good linearity and group delay performance suitable for an equalizer. Using inverter-based delays enables area efficiency as well as the capability to tune the delay across process voltage and temperature (PVT) variations. Since the FFE is an event-driven combinational logic based on the incoming data, it does not require synchronous sampling coming from a high-speed clock and data recovery (CDR), and it is advantageous for high-speed and multirate operation as its power consumption scales with the data rate. Fabricated in 40-nm CMOS technology, the hybrid FFE achieves energy per bit of 2.7 pJ/bit with a 20-dB Nyquist insertion loss link at the 28.57-Gb/s nonreturn to zero (NRZ) data rate.

Comparison of genetic variation between primary colorectal cancer and metastatic peritoneal cancer.

Among cancer metastases by primary colorectal cancer (CRC), peritoneal metastasis is the second most common metastatic lesion after liver metastasis. In treating metastatic CRC, it is very important to differentiate targeted-therapy and chemotherapy according to the characteristics of each lesion because the genetic variation of the primary and metastatic lesions are different. However, there are few studies of genetic characteristics on peritoneal metastasis caused by primary CRC, so molecular-level studies are continuously required. We propose an appropriate peritoneal metastasis treatment policy by identifying the genetic characteristics between primary CRC and synchronous peritoneal metastatic lesions. Primary CRC and synchronous peritoneal metastasis samples were analyzed in pairs from six patients using Comprehensive Cancer Panel (409 cancer-related genes, Thermo Fisher Scientific, USA) and next-generation sequencing (NGS). The mutations were commonly found on the KMT2C and THBS1 genes in both primary CRC and peritoneal metastasis. The PDE4DIP gene was mutated in all cases except for on a sample of peritoneal metastasis. As a result of analysis using the mutation database, we confirmed that the gene mutations of primary CRC and the peritoneal metastasis derived from it showed the same tendency, although we did not accompany the gene expression level or epigenetic study. It is thought that the treatment policy through molecular genetic testing of primary CRC can also be applied to peritoneal metastasis treatment. Our study is expected to be the basis for further peritoneal metastasis research.

Characterization of the immune microenvironment in matched primary and metastatic breast cancer lesions from the AURORA study: BIG 14-01.

1009 Background: Immunotherapy benefit in patients with metastatic breast cancer (MBC) is limited to patients with triple negative breast cancer and PD-L1 expression in the tumor sample. Multi-omics characterization of the anti-cancer immune response in MBC could provide novel insights into the mechanisms behind immune response failure. Methods: The AURORA program (NCT02102165) enrolled patients with MBC who received at most one line of treatment in the metastatic setting. RNA sequencing was performed on primary and metastatic lesions. Stromal tumor infiltrating lymphocytes (sTIL) were scored in line with the International Immuno-Oncology Biomarker Working Group for Breast Cancer recommendations. T cell and B cell receptor (TCR and BCR) analysis was performed with MiXCR. Deconvolution of bulk RNA sequencing data was performed using xCell. ImmuneScore-normalized Relative Abundance metastasis/primary Ratios (RAR) of immune cell types were calculated. All comparisons between primary and metastatic lesions were performed on matched samples. Wilcoxon signed-rank tests were used. Results: As expected, sTILs decreased from primary to metastatic lesion. However, 9% of metastatic lesions still had ⪰20% sTILs. Matched RNA expression data was available for 204 patients. Relative abundance of macrophages (RAR 3.3, p&lt;0.001) and Th1 cells (RAR 1.5, p&lt;0.001) was increased in the metastases, while Treg cells (RAR 0.12, p&lt;0.001), CD8+ T cells (RAR 0.32, p&lt;0.001) and B cells (RAR 0.32, p&lt;0.001) decreased the strongest. Metastases with ⪰20% sTILs had higher Treg cells (p&lt;0.001) and B cells (p&lt;0.001) compared to metastases with low sTILs, which had more Th1 cells (p&lt;0.001), mast cells (p&lt;0.001) and NKT cells (p&lt;0.001). De novo metastatic and synchronous primary samples had more BCR (p&lt;0.001) and TCR (p&lt;0.001) clones in common as compared to non-de novo metastatic cancers. Conclusions: sTIL percentage decreased from primary tumor to metastatic lesion. Metastatic lesions with many sTILs (⪰20%) were enriched for immune response suppressing regulatory T cells. [Table: see text]

Improved demodulated phase signal resolution for carrier signals with small modulation index by clipping and synchronous sampling for heterodyne interferometers

Digitization of phase-modulated carrier signals with a commercially available analog-to-digital converter (ADC) is a common task in many communication and sensor applications. ADCs deliver phase-modulated digital carrier signals, which are numerically demodulated in order to extract the relevant information. However, the limited dynamic ranges of available ADCs limit the carrier-to-noise ratio of carrier signals after digitization. Correspondingly, the resolution of the demodulated digital signal is degraded. We demonstrate a sampling method with a simple demodulation scheme for phase-modulated signals with a small modulation index. Our new scheme overcomes the limitation due to digital noise defined by the ADC. Through simulations and experiments, we provide evidence that our method can improve the resolution of the demodulated digital signal significantly, when the carrier-to-noise ratio of phase-modulated signals is limited by digital noise. We employ our sampling and demodulation scheme to solve the problem of a possible degradation of measurement resolution after digital demodulation in heterodyne interferometers measuring small vibration amplitudes.