An 8.1-ns Column-Access 1.6-Gb/s/pin DDR3 SDRAM With an 8:4 Multiplexed Data-Transfer Scheme

Three circuit techniques for an 8.1-ns column-access 1.6-Gb/s/pin 512-Mb DDR3 SDRAM using 90-nm dual-gate CMOS technology were developed. First, an 8:4 multiplexed data-transfer scheme, which operates in a quasi-4-bit prefetch mode, achieves a 3.17-ns reduction in column-access time, i.e., from 11.3 to 8.13 ns. Second, a dual-clock latency counter reduces standby power by 22% and cycle time from 1.7 to 1.2 ns. Third, a multiple-ODT-merged output buffer enables selection of five effective-resistance values Rtt (20, 30, 40, 60, and 120 Omega) without increasing I/O capacitance. Based on these techniques, 1.6-Gb/s/pin operation with a 1.36-V power supply and a column latency of 7 was accomplished     

Nondestructive readout mode static induction transistor (SIT) photosensors

The nondestructive readout (NDRO) performance of two static induction transistor (SIT) photosensors, a 40×40 pixel area array and a 140-b linear array, is examined. NDRO operation in the SIT sensors is demonstrated by imaging with the area array and by examining the output waveform of the linear array. The charge lost per NDRO cycle in the linear array was 0.014% near the saturation signal level, and no charge loss could be detected at the ⩽0.5 saturation level. NDRO performance in the area array was degraded compared to the linear array, due to the larger value of the load capacitance connected to the output electrode of the SIT. NDRO operation also enables the cancellation of both the photosite reset noise and the signal nonuniformity by subtracting the first NDRO output from the following NDRO outputs, as well as the advantage of monitoring the signal state during the integration period     

Analysis of graded-index polymer optical fiber link performance under fiber bending

Bending effects on bandwidth and loss of a graded-index polymer optical fiber (GI POF) were investigated, and those influences on the optical link performance were discussed simultaneously for the first time. The numerical apertures (NAs) of the GI POFs were deliberately varied from 0.154 to 0.292. A bending radius larger than 10 mm induced little mode coupling and little change in the bandwidth of the GI POF. A bending radius smaller than 10 mm caused degradation in the bandwidths of the higher NA GI POFs. On the other hand, in the lower NA GI POFs, even more severe bending could cause little change in their bandwidths. Thus, the lower NA GI POF seemed preferable in suppressing the bandwidth change. However, the higher NA GI POF exhibited the lower bending loss. The preferable NAs for both characteristics were completely opposite. Moreover, the bending loss under underfilled launch (UFL) could be lower than that under overfilled launch (OFL). On the other hand, the bending loss was equivalent to the bandwidth degradation in view of the link power penalty. Therefore, the bandwidth change and loss caused by the bending were the critical factors to optimize the optical link considering the link power budget. The high-NA GI POF with almost ideal refractive-index profile could provide stable high performance in overgigabit communication even under any bending conditions.     

六输入监控器为汽车系统提供准确电源监视

引言 凌力尔特公司最新的一组电源监控器(包含三款器件)是6输入电压监视器,对当今那些需要进行准确电源监视的多电压系统提供了一种理想选择.LTC2930、LTC2931和LTC2932能够在-40℃至125℃的温度范围内保持1.5%的门限准确度.     

Radiation from the transmission line with an acute bend

The transmission and radiation characteristics at an acute bend of a transmission line are investigated analytically. First, in consideration of the strong coupling to the adjacent conductor, the current distributions are decomposed into even and odd modes. Applying the traveling-wave mode method to these modes, it is shown that transmission characteristics of the line with an acute bend can be easily obtained. The abrupt variation of the voltage near the bend is noted. Next, the discontinuities of the traveling wave currents are regarded as radiating sources and the radiation field from the bend in the transmission line is derived by the summation of fields created by each of the discontinuities. It is found that there exist the electric field component radiating strongly in the directions of propagation of the current and another electric field component radiating strongly into the intermediate direction. Finally, by comparing with the former method and experimental results, the validity of the method is confirmed     

Multidimensional feedforward compensator for industrial systems through pole assignment regulator and observer

A feedforward-compensator-design technique is presented for industrial control systems. The proposed feedforward compensator can improve dynamic characteristics of multidimensional systems by modifying the input signals. The multidimensional feedforward-compensator design is based on the pole assignment regulator, the minimal-order observer, and the conversion from a closed-loop system to an open-loop system. The effectiveness of the proposed feedforward compensator is demonstrated by a simulation study of temperature control of a thermal power plant and by experiments of the contour control of an articulated robot arm.     

Multiobjective genetic algorithm applied to aerodynamic design ofcascade airfoils

A multiobjective genetic algorithm (GA) based on Fonseca-Fleming's Pareto-based ranking and fitness-sharing techniques has been applied to aerodynamic shape optimization of cascade airfoil design. Airfoil performance is evaluated by a Navier-Stokes code. Evaluation of GA population is parallelized on the Numerical Wind Tunnel, a parallel vector machine. The present multiobjective design seeks high pressure rise, high flow turning angle, and low total pressure loss at a low Mach number. Pareto solutions that perform better than existing control diffusion airfoils were obtained     

Control scheme for optimizing the interferometer phase bias in a symmetric-Mach-Zehnder-type all-optical switch

A control scheme for accurately optimizing (and also automatically stabilizing) the interferometer phase bias of symmetric-Mach-Zehnder (SMZ)-type ultrafast all-optical switches is proposed. In this control scheme, weak continuous-wave light is used as supervisory input light and its spectral power ratio at the switch output is used as a bipolar error signal. Our experimental results for 168-Gb/s 16:1 demultiplexing with a hybrid-integrated SMZ switch indicate the feasibility and the sensitivity of this control scheme.     

A low-impedance open-bitline array for multigigabit DRAM

The noise-generating mechanisms inherent in the open-bitline DRAM array using the 6F² (F: feature size) memory cells and techniques for reducing the noise are described. The sources of differential noise coupled to the paired bitlines laid out in two arrays are the p-well, cell plate, and the group of nonselected wordlines. It was found, by simulation and by experiment with a 0.13-μm 256-Mb test chip, that the level of noise is dramatically reduced by using a low-impedance array with careful layout featuring low-resistivity materials, tight bridging between pairs of adjacent arrays, and a small array, achieving a comparable level of noise to that seen in the twisted and folded-bitline array. On basis of these results, it turns out that the open-bitline array has a strong chance of revival in the multigigabit generation, as long as these noise reduction techniques are applied     

Changes in the characteristics of CuInGaSe2 solar cells under light irradiation and during recovery: degradation analysis by the feeble light measuring method

Changes in the characteristics of CuInGaSe₂ solar cells in response to light irradiation were investigated. Then these changes, which suggest long-term degradation, were clarified using the measurement technique by feeble light. The thin-film cell of this type is considered to be “ever stable”. A stable result over the short term was also obtained in the light accelerated test of 2-SUN performed in this experiment. On the other hand, it was found that the characteristics measured with feeble light show a remarkable change over time. As a result of measuring at 0.065–105 mW/cm² light intensity, the change rate of cell output power was so intense the measurement light was weak. This finding reflects the increase in an internal defect and suggests a possibility that light irradiation exerts the influence on long-term cell performance. Moreover, by measuring with feeble light, we found that the changed output recovers by reverse voltage application. The phenomenon of recovery up on comparatively low reverse voltage can be considered as an application for maintaining stability.