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Guidelines toward Self-Organized 3D Integrated Optical Interconnects
Published in Tetsuzo Yoshimura, Self-Organized 3D Integrated Optical Interconnects, 2021
In each level in the hierarchy, as Fig. 2.1b shows, cross-talk, heat generation (power dissipation), RC delay, signal attenuation, and signal reflection are caused. The cross-talk arises from electromagnetic interference, electromagnetic induction, and electrical couplings between metal lines/electrodes due to capacitance, C. The heat generation and RC delay mainly arise from charge-discharge of metal lines/electrodes through electrical resistance, R, of transistors in driver circuits. The signal attenuation arises from electrical resistance, R, of the lines/electrodes including the skin effect. The signal reflection arises from impedance mismatching in electrical circuits. Since the influence of the electromagnetic interference, electromagnetic induction, capacitance, and electrical resistance increases with increasing clock frequency and wiring density, the problems become serious with increases in clock frequency and wiring density in computers. The same situation occurs in switching systems.
PLC cabling, data transmission, and networking
Published in Raymond F. Gardner, Introduction to Plant Automation and Controls, 2020
Modbus technology was developed during the first generations of PLCs and is so robust and reliable that it is still very commonly used in plant controls, even after more than five decades of technology advancements. Modbus is a versatile, easy-to-use, and hearty means of transmitting data over long or short distances. Modbus RS485 uses a serial data link, where the RS485-device cables are daisy-chained from one controller to the next (Figure 18.12). Failure of any device in the string does not interrupt the daisy chain wiring circuit, and all remaining devices continue to communicate. For relatively long runs, the signal conductors at each end of the RS485 daisy chain are connected through terminating resistors, in order to match the cable impedance to the impedance required by the hardware (Figure 18.13). Impedance matching is necessary to avoid signal reflections that would be very problematic at high data-transmission rates. Signal reflections can also distort the original signal, reducing reliability.
Paradigm Shift of On-Chip Interconnects from Electrical to Optical
Published in Thomas Noulis, Noise Coupling in System-on-Chip, 2018
Swati Joshi, Amit Kumar, Brajesh Kumar Kaushik
Reflections in the transmission line occur when traveling waves see discontinuities on the line. Discontinuity is defined as any change in line impedance. Changes in paths of the signal, such as vias, bends, wire crossovers, bonding wires, and so on, result in signal reflection. At high data rates, this issue needs to be taken into consideration. Electromagnetic interference (EMI) results from the external noise source or coupling between subsystems. The noise in the ground cable and power line can adversely affect circuit operation. EMI suppression uses techniques such as shielding, decoupling, and grounding [25]. All of the above effects (crosstalk, EMI, ringing, reflections in a transmission line, etc.) degrade the quality of the received signal, corrupt the signal, and can affect the signal traveling on the same interconnect line at a later time, resulting in inter-symbol interference (ISI), that is, energy transfer from one signal in the interconnect channel to a later unrelated signal as illustrated in Figure 14.10.
Application of Behavioral Psychology in Clothing Design from The Perspective of Big Data
Published in Applied Artificial Intelligence, 2023
It can be seen that to improve the common mode rejection capability, We can increase differential voltage gain or decrease common mode voltage gain to increase or decrease the CMRR, which is the ratio of differential voltage gain to common mode voltage gain. Emitter resistance RE should be raised to increase CMRR. The CMRR’s value is frequently influenced by signal frequency. Where, the closed-loop gain, resistance matching accuracy, and of the amplifier circuit must be considered, that is, the multi-op-amp differential amplifier circuit of the following parts should be used. Designing source and load impedances for resistance matching reduces signal reflection or increases power transfer. A circuit’s mismatched resistance will cause a reflection of the signal back to its source. The power transmitted downstream to a load is lessened when a signal reflects. Impedance matching serves the twin purpose of minimizing reflections while facilitating power transmission into a load.
Ionospheric delay estimation of Loran skywave using simple cosine model
Published in Electromagnetics, 2023
Kai Zhang, Fan Yang, WeiDong Wang, Chen Zheng, Borong Zou, Hui Li
However, the real ionosphere is complex and hard to predict because of the changes in time, climate, location, and environment. In (2022), parameters such as ionospheric electron density, collision frequency and signal reflection height will all affect the calculation results. The electron density and collision frequency are empirical models based on large number of measured data, so there will be errors in the calculation process. Signal reflection height is affected by signal frequency, seasonal time, solar activity, and geographical location. In summary, the calculation of LF skywave delay passing through the ionosphere is very complicated. It contains a large number of engineering approximations, such as geometrical optics path approximation, diffraction correction, earth radius equivalent correction, and isotropic anisotropic boundary condition. It also includes empirical correction models like solar activity and seasonal and electron density variations. The whole process is difficult to apply directly to augmenting the Loran receiving system. Moreover, many conditions cannot be accurately given under the actual signal propagation conditions, and there will be additional errors. A simple and effective calculation method is needed for the system single-frequency user in order to achieve accurate time delay estimation of the skywave.
A novel context-aware system to improve driver’s field of view in urban traffic networks
Published in Journal of Intelligent Transportation Systems, 2022
A. Nourbakhshrezaei, M. Jadidi, M. R. Delavar, B. Moshiri
where represents the vehicle movement. In order to prevent additional processing on the main server, the mentioned condition is checked on the client’s application. GPS positions are recorded as Latitude and Longitude with respect to the WGS84 reference ellipsoid. As the smartphone application is used to find the location of the vehicles, the accuracy of the positioning is related to the quality of the GPS antenna embedded in the smartphones. The mean accuracy in an urban environment is about 3 meters under good condition (Dabove & Di Pietra, 2019). However, there is a strong correlation between the accuracy and building’s height. The height of buildings can affect accuracy in two ways: a) Satellite signal blockage (Tirkas et al., 1998) and b) Signal reflection (multi-path) (Byun et al., 2002). These two errors decrease accuracy to up to 15 meters in some places. The accuracy is acceptable since the purpose of using GPS data in this research is to calculate the relative distance between camera’s location (east, west, north, south) and the vehicles near to RSU. To classify vehicles regarding their distances from the RSUs, ellipsoid curvilinear positions should be projected to the plane using UTM projection system.