1,720,971 research outputs found
Dual channel time-to-digital converter module with 10 ps resolution and 320 ns full scale range
Full text linkA dual-channel time-to-digital converter (TDC) module designed to accurately measure time intervals with 10 ps resolution, about 21 ps root-mean-square (rms) precision and 125 fs rms differential nonlinearity, over a 320 ns full scale range and up to 4 Mconv/s per channel is presented. The module can also operate the two channels in parallel, as a single TDC converter, in order to improve timing performance to about 15.3 ps rms. A USB 2.0 interface provides the power supply and allows fast data transfer to a computer, where a dedicated software interface handles measurement data and plots. Because of the excellent timing performance, compact dimensions and low power consumption, the dual-channel TDC module is suitable for advanced multi-channel time measurements at the picosecond level
Eight-Channel 21 ps Precision 10 μs Range Time-to-Digital Converter Module
No full textWe present an eight-channel time-to-digital converter (TDC) instrument capable of measuring up to eight independent time intervals, with 21 ps rms precision and less than 1.5% LSB rms differential nonlinearity, over 10 μs full-scale range and up to 5.5 Mconv/s per channel. The module can also operate the eight channels in average or interleaved mode, i.e., as a single TDC, in order to improve timing performance or conversion rate, respectively. The on-board real-time data processing allows fast data transfer to a remote computer, through a Universal Serial Bus 2.0 interface, and a dedicated software interface handles measurements and plots data. Thanks to excellent timing performance and just 6 W power consumption, the eight-channel TDC module is suitable for advanced cost-effective multichannel time measurements at picosecond level
32 × 32 CMOS SPAD Imager for Gated Imaging, Photon Timing, and Photon Coincidence
No full textWe present the design and simulations of a single-photon sensitive imager based on single photon avalanche diodes (SPADs) with an innovative pixel architecture that includes four separate SPADs with independent active time-gating and quenching circuit, a shared time-to-digital converter (TDC) with 50-ps resolution, four independent photon counters, and multiple operation modes. The TDC is driven by smart arbitration logic, which preserves spatial information among the four detectors; furthermore, an alternative operation mode exploits photon-coincidence on multiple detectors to reduce the effect of high background levels, e.g., in light detection and ranging applications with strong ambient light. Key features are the ability to operate in simultaneous photon counting and timing modes for capturing 2-D and 3-D images of the scene in a single shot (frame), the option of a counting-only mode, reducing power consumption, and increasing achievable frame-rate when timing information is not needed, and the ability to individually shut down noisy detectors or to enable just some regions of interests
Miniaturized 64-channel single-photon timing system
Full text linkWe present a portable 64-channel photon-counting system employing a monolithic array of Single-Photon Avalanche Diodes (SPADs) and a custom-designed Time-to-Digital Converter (TDC), for single-photon counting and timing applications. The system provides state-of-art singlephoton detection performance and time-resolved measurement capability, with timing precision down to 100 ps FWHM and linearity better than 2% LSB (RMS). The compact form factor (1â3 diameter by 2â3 length), extensive customization capabilities, and low power consumption enable its use in applications requiring both high-end single-photon performance and system portability, such as wearable health monitoring, hand-held equipment, and automotive time-of-flight 3D ranging measurement
Design of a 16 x 16 fast-gated SPAD imager with 16 integrated shared picosecond TDCs for non-line-of-sight imaging
Full text linkTime-to-digital converter card for multichannel time-resolved single-photon counting applications
Full text linkWe present a high performance Time-to-Digital Converter (TDC) card that provides 10 ps timing resolution and 20 ps (rms) timing precision with a programmable full-scale-range from 160 ns to 10 mu s. Differential Non-Linearity (DNL) is better than 1.3% LSB (rms) and Integral Non-Linearity (INL) is 5 ps rms. Thanks to the low power consumption (400 mW) and the compact size (78 mm x 28 mm x 10 mm), this card is the building block for developing compact multichannel time-resolved instrumentation for Time-Correlated Single-Photon Counting (TCSPC). The TDC-card outputs the time measurement results together with the rates of START and STOP signals and the number of valid TDC conversions. These additional information are needed by many TCSPC-based applications, such as: Fluorescence Lifetime Imaging (FLIM), Time-of-Flight (TOF) ranging measurements, time-resolved Positron Emission Tomography (PET), single-molecule spectroscopy, Fluorescence Correlation Spectroscopy (FCS), Diffuse Optical Tomography (DOT), Optical Time-Domain Reflectometry (OTDR), quantum optics, etc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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