scholarly journals ANALISIS PERBANDINGAN PERFORMANSI SISTEM RADIO OVER FIBER ANTARA MENGGUNAKAN RADIO TO OPTIC DIRECT CONVERSION DAN IM/DD

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Helmi Setiawan ◽  
Erna Sri Sugesti ◽  
Suwandi Suwandi
Keyword(s):  
Direct Detection ◽  
Direct Conversion ◽  
Base Station ◽  
Radio Over Fiber ◽  
Intensity Modulation ◽  
Modulation Index ◽  
Heterodyne Detection ◽  
Optical Modulation ◽  
Noise Ratio

Jurnal ini mengevaluasi sistem radio over fiber (ROF) menggunakan radio-to-optic direct conversion (ROC) bertingkat, baik ROC/heterodyne detection (HD) maupun ROC/ self heterodyne detection (SHD). Sistem ROF menggunakan intensity modulation/direct detection (IM/DD) bertingkat berdasarkan parameter carrier to noise ratio (CNR). Optimalisasi nilai optical modulation index (OMI) yang dilakukan pada sistem ROF menggunakan ROC bertingkat, karena performansi CNR dari sistem dengan OMI yang identik kurang baik. Dengan menggunakan metoda optimalisasi OMI, CNR sistem ROC/HD dan ROC/SHD lebih besar 18 dB dan 15 dB dari sistem IM/DD untuk bandwidth sinyal RF sebesar 150 MHz dan jumlah Radio Base Station (RBS) yang terkoneksi (N) = 20. Sedangkan untuk bandwidth sebesar 50 MHz dan N = 20, CNR sistem ROC/HD dan ROC/SHD lebih besar 20 dB dan 17 dB.Kata kunci: radio over fiber, radio-to-optic direct conversion, heterodyne detection, self heterodyne detection

Unique Word DMT Schemes for Optical Systems With Intensity Modulation and Direct Detection

2017 ◽  
Vol 35 (18) ◽  
pp. 3862-3869 ◽  
Author(s):  
Sher Ali Cheema ◽  
Emilio Rafael Balda ◽  
Mike Wolf ◽  
Martin Haardt
Keyword(s):  
Direct Detection ◽  
Intensity Modulation ◽  
Optical Systems ◽  
Unique Word

Modulation index dependence of intensity modulation bandwidth in visible light communications

2018 ◽  
Vol 43 (19) ◽  
pp. 4570 ◽  
Author(s):  
Zi-Yang Wu ◽  
Xiao-Yu Liu ◽  
Jiang-Shan Wang ◽  
Jiao Wang
Keyword(s):  
Visible Light ◽  
Intensity Modulation ◽  
Modulation Index ◽  
Modulation Bandwidth ◽  
Visible Light Communications

Direct conversion semiconductor detectors in positron emission tomography

2015 ◽  
Vol 30 (14) ◽  
pp. 1530011 ◽  
Author(s):  
Joshua W. Cates ◽  
Yi Gu ◽  
Craig S. Levin
Keyword(s):  
Positron Emission Tomography ◽  
Direct Detection ◽  
Direct Conversion ◽  
Image Resolution ◽  
Emission Tomography ◽  
Semiconductor Detectors ◽  
Ongoing Research ◽  
Tumor Delineation ◽  
Positron Emission ◽  
Quantitative Accuracy

Semiconductor detectors are playing an increasing role in ongoing research to improve image resolution, contrast, and quantitative accuracy in preclinical applications of positron emission tomography (PET). These detectors serve as a medium for direct detection of annihilation photons. Early clinical translation of this technology has shown improvements in image quality and tumor delineation for head and neck cancers, relative to conventional scintillator-based systems. After a brief outline of the basics of PET imaging and the physical detection mechanisms for semiconductor detectors, an overview of ongoing detector development work is presented. The capabilities of semiconductor-based PET systems and the current state of these devices are discussed.

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