12 research outputs found

    Bandwidth of linearized electrooptic modulators

    Get PDF
    Many schemes have been proposed to make high dynamic range analog radio frequency (RF) photonic links by linearizing the transfer function of the link's modulator. This paper studies the degrading effects of finite transit time and optical and electrical velocity dispersion on such linearization schemes. It further demonstrates that much of the lost dynamic range in some modulators may be regained by segmenting and rephasing the RF transmission line

    Effects of Velocity Mismatch and Transit Time on Linearized Electro-Optic Modulators

    Get PDF
    The program written for this study allows calculations for periodically-rephased modulators since the modulator is already broken up into a series of incremental matrices. Thus if the modulator is allowed to be mismatched for a few matrices and then rephased for the next few and so on, we have the results shown for a four segment modulator (3 rephasings). modulators are considered

    Linearized modulators for analog photonic links

    Get PDF
    The potential applications of high dynamic range analog RF photonic links include antenna remoting, photonic-coupled phased-array antennas, and cable-television transmission. This paper compares the results obtained with a number of different electro-optic modulator types and link configurations assuming an ideal velocity-matched modulator. The degrading effects of velocity mismatching are also presented for some of the modulators studied

    Antenna-Coupled Millimeter-Wave Electro-optic Modulators for 20 to 100 GHz

    Get PDF
    Coupling the signal to the electrodes of an integrated electro-optical modulator with an array of antennas is used to velocity-match the modulation and optical waves, greatly extending-the length-to-modulation frequency product of the modulator. In addition, antenna coupling eliminates the parasitic elements associated with coax connectors, matching transformers and bond wires. This paper summarizes the results obtained to date with this technique at 20 to 100 GHz, with phase modulators, Mach-Zehnder modulators, and delta-beta directional coupler modulators

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

    Get PDF
    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Die Antimykotica

    No full text
    corecore