We investigate signal-to-noise ratio (SNR) characteristics of an 850-nm optoelectronic integrated circuit (OEIC) receiver fabricated with standard 0.25-µm SiGe bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. The OEIC receiver is composed of a Si avalanche photodetector (APD) and BiCMOS analog circuits including a transimpedance amplifier with DC-balanced buffer, a tunable equalizer, a limiting amplifier, and an output buffer with 50-Ω loads. We measure APD SNR characteristics dependence on the reverse bias voltage as well as BiCMOS circuit noise characteristics. From these, we determine the SNR characteristics of the entire OEIC receiver, and finally, the results are verified with bit-error rate measurement.
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http://dx.doi.org/10.1364/OE.22.000900 | DOI Listing |
Sensors (Basel)
January 2025
School of Information Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Spectrum sensing is recognized as a viable strategy to alleviate the scarcity of spectrum resources and to optimize their usage. In this paper, considering the time-varying characteristics and the dependence on various timescales within a time series of samples composed of in-phase (I) and quadrature (Q) component signals, we propose a multi-scale time-correlated perceptual attention model named MSTC-PANet. The model consists of multiple parallel temporal correlation perceptual attention (TCPA) modules, enabling us to extract features at different timescales and identify dependencies among features across various timescales.
View Article and Find Full Text PDFJ Magn Reson Imaging
January 2025
Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, Jiangsu, China.
Background: At high magnetic fields, degraded image quality due to dielectric artifacts and elevated specific absorption rate (SAR) are two technical challenges in fetal MRI.
Purpose: To assess the potential of high dielectric constant (HDC) pad in increasing image quality and decreasing SAR for 3 T fetal MRI.
Study Type: Prospective.
J Magn Reson
January 2025
UC Berkeley - UCSF Graduate Program in Bioengineering, 1700 4th St, San Francisco, CA 94158, USA; Radiology and Biomedical Imaging, University of California, San Francisco, 1700 4th St, San Francisco, CA 94158, USA.
Fitting rate constants to Hyperpolarized [1-C]Pyruvate (HP C13) MRI data is a promising approach for quantifying metabolism in vivo. Current methods typically fit each voxel of the dataset using a least-squares objective. With these methods, each voxel is considered independently, and the spatial relationships are not considered during fitting.
View Article and Find Full Text PDFAnal Chem
January 2025
College of Chemistry and Material Science, Northwest University, Xi'an 710127, China.
With rapid, energy-intensive, and coal-fueled economic growth, global air quality is deteriorating, and particulate matter pollution has emerged as one of the major public health problems worldwide. It is extremely urgent to achieve carbon emission reduction and air pollution prevention and control, aiming at the common problem of weak and unstable signals of characteristic elements in the application of laser-induced breakdown spectroscopy (LIBS) technology for trace element detection. In this study, the influence of the optical fiber collimation signal enhancement method on the LIBS signal was explored.
View Article and Find Full Text PDFBMJ Open
December 2024
National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
Introduction: Individuals with hearing loss and hearing aid users report higher levels of listening effort and fatigue in daily life compared with those with normal hearing. However, there is a lack of objective measures to evaluate these experiences in real-world settings. Recent studies have found that higher sound pressure levels (SPL) and lower signal-to-noise ratios (SNR) are linked to increased heart rate and decreased heart rate variability, reflecting the greater effort required to process auditory information.
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