• Journal of Broadcast Engineering
• /
• v.21 no.6
• /
• pp.986-994
• /
• 2016

In this paper, a digital closed-circuit television (CCTV) transmission system called the extended reach high definition serial digital interface (ER-SDI) is proposed to increase the transmission distance while preserving the quality using digital modulation. The current standard of HD-serial digital interface (HD-SDI) has the maximum transmission distance of 200 m. Recently, one system which transforms the digital signal to an analog signal and modulates color signal to extend the transmission distance is proposed. Another system which uses IP network is also proposed. However, the former system has a disadvantage of video quality and the latter system has high latency. The proposed ER-SDI is designed to extend the transmission distance of 518 m by adopting multilevel constellations and a channel code for a data rate of 1.485 Gbps. The maximum transmission distance of the proposed system is calculated using the specification of HD-SDI and the experiment result under coaxial cable environment.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.1A
• /
• pp.74-80
• /
• 2000

In this paper, we proposed the MAC protocol and analyzed the performance for CATV/LAN network which was based upon HFC(hybrid optic coaxial) increased abruptly as alternative method of high speed network. Upstream channel which analyzed very deeply for CATV/LAN network have the preferential access property depending upon that position and unidirectional property. To solve this fairness problem, we propose the CSMA-CD/U/P protocol that transm it as $P_i$ probability although data packets is immediately transmitted when it was occurred. As the analytic result and simulation, we obtained $P_i$ value and its average delay time. Also, we get its variance value and queue length distribution. The mean delay time and queue length increase as the load and number of stations increase in the CATV/LAN network.

• Journal of the Korean Society of Radiology
• /
• v.17 no.2
• /
• pp.175-184
• /
• 2023

Based on the actual shape of the detector and the data provided by the manufacturer, the shape of the detector was implemented through Penelope simulation and applied to the appropriate four-layer thickness based on the efficiency obtained from the measurements. Efficiency calculations to determine the effect of the simulated number of Full Energy Peak Efficiency(FEPE) channels in the detector and the outside contact layer in the crystal on the Full Energy Peak Efficiency were performed for various four-layer thicknesses of 0.3, 0.5, 0.7, 1.0, 1.2, and 1.4 mm using the Penelope Code. When the thickness of the external contact layer was increased by 5 times, the Full Energy Peak Efficiency decreased by about 36% for 59.50 keV, and the Full Energy Peak Efficiency decreased by 10% for 1836. In addition, as it increased by 10 times, the Full Energy Peak Efficiency decreased by about 20% for 59.54 keV, and 7% for 1836.01 keV. The Penelope simulated Full Energy Peak Efficiency channel decreases exponentially with the increase in the four layers. In addition, it was confirmed that the total effect curve was well matched with a relative difference of less than 3.5% in the 0.3-1.4 mm dead layer thickness region. However, it was found that the inhomogeneous dead layer is still a parameter in the Monte Carlo model.