Narrow Results

We present design considerations for high speed high swing differential modulator drivers in SiGeBiCMOS technology. Trade-offs between lumped and distributed designs, and linear and limiting amplifiers are examined. The design of a 6 V output modulator driver is discussed in detail. The driver features a unique bias generation and distribution circuit that enables low power-supply operation. Simulation results and measurements are given.

Inter symbol interference (ISI) caused by dispersion in optical fibers is the major limiting factor on the achievable data rate or transmission distance in high-speed fiber-optic interconnects¹. Compared with optical-domain and other electrical-domain dispersion compensation methods, duobinary coding technology is used due to its higher spectral efficiency. In this paper, a monolithically integrated duobinary optical transmitter has be designed and fabricated in standard 0.18 μm CMOS technology. This transmitter consists of a duobinary encoder and a VCSEL driver. The master-slave D flip-flop structure is used to generate the wideband one bit delay which is important for the realization of duobinary signal. An open drain structure is used in VCSEL driver design to provide the higher current output in low supply voltage condition. This duobinary transmitter can operate up to 5 Gb/s with 20 mA current output. The current consumption is only 50 mA under 1.8 V supply voltage.

As a traffic language, sharp turn sign is a kind of important road infrastructure that indicates a sharp turning will show up at the coming road, warning drivers to slow down to ensure the driving safety. In this paper, real vehicle test was carried out on mountain road with an eye tracker equipment. At different driving speeds, parameters of eye movement characteristics in the visual cognition process of sharp turn signs were collected, including distribution of gaze points, fixation and saccade. Simultaneously, driver’s scan paths of recognizing sharp turn signs with different supporting forms were gathered. The results of the analysis of testing data showed that the dispersion of distribution of gaze points would increase with driving velocity. Saccade was the main method for driver to capture information of sharp turn signs. While driving speed was lower than 60km/h, fixation was also one of the methods. For the visual cognition process of sharp turn sign with cantilever, compared to post, the searching scope was wider both in horizontal and vertical directions. This study is beneficial to evaluate the rationality of sharp turn signs, promoting the using efficiency of signs and improving the driving safety on mountain road.

Memory demand is associated with increased mental workload. The objective of the present study was to examine the effects of visuospatial memory secondary tasks on driving performance. Memory tasks for the unknown word-figure pairs and recognition tasks for word-figure pairs at two-level difficulties were employed separately to represent working memory’s process and long-term memory’s process. A simulator study was conducted based on the simulation of the standard environment of Lane change test (LCT). The performance of lane keeping, lane change, and secondary tasks was measured by statistical methods. The comprehensive appraisal model was constructed to quantify total driving performance. The results showed that the mean path deviation, steering angle, and lane excursion times increased, and the proportion of correct lane change decreased, with the perceived workload increasing and the total driving performance decreasing in dual-task driving condition. Compared with the simple working memory group, as the difficulty of tasks increased in difficult working memory group, lane change performance degraded and the perceived workload increased. In contrast to difficult working memory group, the performance of lane keeping and lane change increased, while the perceived workload decreased and the total performance increased by about 50% in difficult recognition group. There were few differences between the simple working memory group and simple recognition group. The difficult working memory group had the lowest total driving performance. The results indicate that as the secondary task’s difficulty increases, driving performance will degrade. Performance improves significantly when the working memory process is converted to the recognition process. This trend is more obvious when the memory task assumes to be more difficult.

The design and optimization procedure for a loudspeaker driven 10-W cooling power thermoacoustic refrigerator components with a temperature difference of 120 K has been discussed using the linear thermoacoustic theory. The resonator losses are proportional to surface area and the optimum diameter ratio of small and large resonator tubes for minimum heat loss for a quarter-wavelength hemispherical ended resonator design is discussed. The hemispherical ended resonator design is further analytically optimized to increase COP, cooling effect at cold heat exchanger and power density by decreasing total resonator surface area and volume. An alternate convergent-divergent resonator design is proposed which is found to be more efficient compared to previous published designs. Resonator designs are tested with DeltaEC software, which predicts a lowest temperature of -48°C and -47°C for the improved hemispherical and convergent-divergent resonator designs, respectively. Theoretical results are in good agreement with DeltaEC results.

Thermoacoustic refrigeration, a novel technology, uses eco-friendly gases like helium, air or the mixture of noble gases as working substances in the absence of moving parts. The design, optimization and analysis of thermoacoustic refrigerators using helium and air as oscillating gases are discussed. Pure helium is chosen since it is proven as the best and economical working gas compared to the alternate pure or the mixture of noble gases. Air is chosen since it is abundant in nature and the least cost of the pressurized dry air cylinders. The design optimization strategies discussed in this paper serve as a guide for aspiring researchers in the design and development of thermoacoustic coolers. Cooling power as a function of stack diameter is discussed. Theoretical results of the optimized coolers are compared with DeltaEC simulation results for validation and are in agreement with each other.

We present design considerations for high speed high swing differential modulator drivers in SiGe BiCMOS technology. Trade-offs between lumped and distributed designs, and linear and limiting amplifiers are examined. The design of a 6 V output modulator driver is discussed in detail. The driver features a unique bias generation and distribution circuit that enables low power-supply operation. Simulation results and measurements are given.

Inter symbol interference (ISI) caused by dispersion in optical fibers is the major limiting factor on the achievable data rate or transmission distance in high-speed fiber-optic interconnects¹. Compared with optical-domain and other electrical-domain dispersion compensation methods, duobinary coding technology is used due to its higher spectral efficiency. In this paper, a monolithically integrated duobinary optical transmitter has be designed and fabricated in standard 0.18 μm CMOS technology. This transmitter consists of a duobinary encoder and a VCSEL driver. The master-slave D flip-flop structure is used to generate the wideband one bit delay which is important for the realization of duobinary signal. An open drain structure is used in VCSEL driver design to provide the higher current output in low supply voltage condition. This duobinary transmitter can operate up to 5 Gb/s with 20 mA current output. The current consumption is only 50 mA under 1.8 V supply voltage.

Based on three kinds of coach, the authors study on protection ability of semi-integral and unitary coach body and two point and three point seat belt from driver room deformation, test dummies damage value and the acceleration value of test dummies head by applying test of coach front impact at speed of 30km/h. The result showed that: the driver room deformation of unitary coach body is larger than semi-integral coach body. The acceleration value of test dummies head in passenger seat of unitary coach body is smaller than semi-integral coach body. The maximum acceleration value of passenger head is more than 200g when using two point seat belt and passenger neck is badly hurt because two point seat belt just only fix waist. The maximum acceleration value is less than 35g when using three point seat belt. So three point seat belt can protect passenger better than two point seat belt.