Junseok HAN Dongsup SONG Hagbae KIM YoungYong KIM Sungho KANG
In order to provide an efficient test method for PLL which is a mixed-signal circuit widely used in most of SoCs, a novel BIST method is developed. The new BIST uses the change of phase differences generated by selectively alternating the feedback frequency. It provides an efficient structural test, reduces an area overhead and improves the test accessibility.
Werner JOHLER Alexander NEUHAUS
Modern telecom and signal relays have been optimized to carry and switch low signals and to withstand high dielectric strength. Recent designs have extremely small physical dimensions and are comparatively cheap. Small size and low cost also make this type of relay very attractive for industrial and automotive applications. For industrial and automotive applications performance characteristics other than low and stable contact resistance values are of importance. While, for industrial applications, safety aspects and inductive load switching characteristics are of major importance, in automotive applications, high switching currents, inductive and lamp loads and high ambient temperatures are essential. Tests were carried out in order to determine the limitations of small size relays. The results obtained clearly show the unexpectedly high load range which signal relays are able to cover. Despite their small size, these relays can handle switching loads up to several hundred volts and currents up to 5 A. On top of the high switching current there is high excess current capability, and relays can work at extreme ambient temperatures between -55 and more than +105 degrees C.
Chunlei ZHANG Weisheng HU Yaohui JIN
In this paper, a new Mixed Integer Linear Programming algorithm is proposed to resolve the light-tree routing and wavelength assignment with wavelength continuity constraints. The node in our system is limited branching and power-efficient multicast capable OXC. Numerical results are given and discussed to show the efficiency of our algorithm.
Retdian Agung NICODIMUS Shigetaka TAKAGI
A feedforward-based active shielding technique for digital noise suppression is more preferred for its capability of reducing the noise on the entire area inside the guard ring. In order to compensate for the variation of substrate parameters, an automatic control scheme to tune the gain of the active shield circuit is proposed. Simulation results show the effectiveness of the proposed system in reducing the digital noise regardless of circuit layout. Simulation results also show that noise suppression improvement from passive guard ring to active shield with tuning is 20 dB or one tenth while that from active shield without tuning to active shield with tuning is 12 dB.
This paper describes a high-speed D/A converter design for mixed-mode systems. Capacitive coupling induced by inter-chip interconnects and time-variant clock skew between ICs should be considered for mixed-mode systems, and on-chip interconnects should be treated as transmission lines in the circuit simulation as operating speed reaches GHz range. A robust FIFO built in the D/A converter can absorb input data timing variance due to the capacitive coupling and the clock timing skew, the worst-case margin of which is 1.5TCLK. Distributed RLC transmission line models for on-chip interconnects produce accurate simulation results at 1 GHz clock frequency over lumped models. For optimized D/A converter design, behavioral modeling methodology is also presented in this paper. Measurement results verify the accuracy of the on-chip interconnect and behavioral models.
Atsushi ONDA Tomoyuki OKU Eddie YU Yoshie LEE Ikuro CHOH Pei-Yi CHIU Jun OHYA
In this paper we describe a mixed reality-supported interactive viewing enhancement museum display system: Visual-dimension Interact System (VIS). With a transparent interactive interface, the museum visitor is able to see, manipulate, and interact with the physical exhibit and its virtual information, which are overlapped on one other. Furthermore, this system provides the possibility for visitor to experience the creation process in an environment as close as possible to the real process. This has the function of assisting the viewer in understanding the exhibit and most importantly, gaining a so-to-speak hands-on experience of the creation process itself leading to a deeper understanding of it.
Eiji KONAKA Takashi MUTOU Tatsuya SUZUKI Shigeru OKUMA
Programmable Logic Controller (PLC) has been widely used in the industrial control. Inherently, the PLC-based system is a class of Hybrid Dynamical System (HDS) in which continuous state of the plant is controlled by the discrete logic-based controller. This paper firstly presents the formal algebraic model of the PLC-based control systems which enable the designer to formulate the various kinds of optimization problem. Secondly, the optimization problem of the 'sensor parameters,' such as the location of the limit switch in the material handling system, the threshold temperature of the thermostat in the temperature control system, is addressed. Finally, we formulate this problem as Mixed Logical Dynamical Systems (MLDS) form which enables us to optimize the sensor parameters by applying the Mixed Integer Programming.
Retdian A. NICODIMUS Hiroto SUZUKI Kazuyuki WADA Shigetaka TAKAGI
A design optimization of active shield circuit using noise averaging method is proposed. The relation between the averaged noise and the design parameters of the active shield circuit such as circuit gain and on-chip layout is examined. A simple design guideline is also provided. Simulation results show that the active shield circuit designed by the proposed optimization method gives a better noise suppression performance of about 28% than the conventional one.
Retdian A. NICODIMUS Shigetaka TAKAGI Kazuyuki WADA
An active shield circuit which effectively reduces the substrate noise on the entire area inside the guard ring regardless of the noise source position is proposed. Simulation result shows that the proposed circuit can reduce the noise level to -85 dB while a conventional guard ring gives -52 dB.
Various effective and draft legislations and rules in Europe (WEEE--Waste Electrical and Electronic Equipment ROHS--Restrictions on the use of certain substances and ELV--End of life of vehicles) and Japan (Recycling Law for Home Electric Appliances) have either targeted restrictions or fully banned on the use of lead, to be enforced from 2001, 2003 and 2006 onwards. Up to now, mainly tin-lead alloys have been used in electronics. The process temperatures usually applied have been in the range of 230. All currently discussed lead-free alternatives for professional electronics need process temperatures which are at least 20 higher. In addition, the process duration is significantly longer. The combination of higher process temperatures and longer duration results in significant thermal stress on electromechanical devices. In particular the precision mechanics of electromechanical relays must withstand the solder process with maximum process temperatures of 255 without dimensional changes. During the transition from tin-lead to lead-free solder processes all combinations of component surfaces and solder must be possible. The selection of pure Sn100 or SnCu0.7 as terminal surface allows mixed assemblies with tin-lead as well as lead-free solders. All tested combinations of terminal surface, PCB surface and solder showed good results. From these results it can be concluded that mixed assemblies are possible during the transition time without any negative impact on the reliability of the electronic devices.
An algorithm is developed for augmenting a real video with virtual graphics objects without computing Euclidean information. For this, we design a method of specifying the virtual camera that performs Euclidean orthographic projection in recovered affine space. In addition, our method has the capability of generating views of objects shaded by virtual light sources. Our novel formulation and experimental results are presented.
Application area of mixed signal technology is currently expanded to digital communication, networking, and digital storage systems from conventional digital audio and video systems. Digital consumer electronics are emerged and their markets are extremely increased. Rapid progress of integrated circuit technology has enabled a system level integration on a SoC. Thus mixed signal SoC becomes a majority in LSI industry. Almost all the analog functions should be realized by CMOS technology on SoC, yet some difficulties such as a low transconductance, a large mismatch voltage, and a large 1/f noise should be solved. CMOS device has been considered as a poor device for the analog use, however in reality, it has attained a remarkable progress for analog applications. CMOS device has a variety of circuit techniques to address its own issues and also has an analog performance that increases rapidly with technology scaling. The mixed signal SoC needs a new development strategy and design methodology that covers from system level to device level for addressing tough needs for a shorter development time, a lower cost, and a higher design quality. The optimizations over analog and digital and over system to device must be established for the development success. Difficulty of low voltage operation of further scaled CMOS in analog circuits will be the most serious issue. This results in the saturation of performance and increase of cost. The system level optimization over analog and digital, digital calibration and compensation, and the use of sigma-delta modulation method will give us the solution.
Michinari SHIMODA Ryuichi IWAKI Masazumi MIYOSHI
The electromagnetic scattering of a plane wave by an inhomogeneous plane whose surface impedance changes locally on the plane is treated. A boundary-value problem is formulated to describe the scattering phenomenon, in which the boundary condition depends on the surface impedance of the plane. Application of the Fourier transform derives an integral equation, which is approximately solved by the method of least-squares. From the solution of the equation, the scattered field is obtained by the inverse Fourier transform. By the use of the incomplete Lipschitz-Hankel integral for the computation of the field, numerical examples are given and the scattering phenomenon is discussed.
Valery AXELRAD Yoon HUH Jau-Wen CHEN Peter BENDIX
Interactions between ESD protection devices and other components of a chip can lead to complex and not easily anticipated discharge bevahior. Triggering of a protection MOSFET is equivalent to the closing of a fast switch and can cause substantial transient discharge currents. The peak value of this current depends on the chip capacitance, resistance, properties of the protection clamp, etc. Careful optimization of the protection circuit is therefore necessary to avoid current overstress and circuit failure.
Keiko Makie-FUKUDA Toshiro TSUKADA
This paper describes fully integrated active guard band filters for suppressing the substrate coupling noise and their noise suppression effect measured by test chip experiments. The noise cancellation circuit of the active guard band filters simply consists of an inverter and a source follower. The substrate noise suppression effect was measured by using a test chip fabricated in a 0.18 µm CMOS triple-well process for system-on-a-chip. The noise with the filter was less than 5% of that without the filter and the noise suppression effect was observed from 1 MHz to 200 MHz by the statistical measurement of the voltage comparator. The noise suppression effect was also observed for actual digital switching noise produced by digital inverters. Configuration of the active guard band filter was investigated by simulation and it is shown that high and uniform noise suppression effect is achieved by placing the guard bands in the L-shape around the target triple-well area on the p-substrate.
This paper proposes an operation-region model for analyzing and testing analog and mixed-signal circuits, which is based on observation of change in MOSFET operation regions. First, the relation between the change in MOSFET operation regions and the fault behavior of a mixed-signal circuit containing a bridging fault is investigated. Next, we propose an analysis procedure based on the operation-region model and apply it to generate the optimal input combination for testing the circuit. We also determine which transistors should be observed in order to estimate the circuit behavior. Since the operation-region model is a method for modeling circuit behavior abstractly, the proposed method will be useful for modeling circuit behavior and for analyzing and testing many kinds of analog and mixed-signal circuits.
Algorithms are presented for the four elementary arithmetic operations, to perform reliable floating-point arithmetic operations. These arithmetic operations can be achieved by applying residue techniques to the weighted number systems and performed with no accuracy lost in the process of the computing. The arithmetic operations presented can be used as elementary tools (on many existing architectures) to ensure the reliability of numerical computations. Simulation results especially for the solutions of ill-conditioned problems are given with emphasis on the practical usability of the tools.
Young-Yong LEE Sang-Mun LEE Hyung-Jin CHOI
In this paper, the forward link erlang capacity and outage probability for hierarchical cellular system based on 2 layer macrocell/microcell are derived analytically by considering the impact of imperfect power control and soft hand-off. The analysis on the outage probability is carried out using two methods: lognormal approximation and Chernoff upper bound. We assume that voice and multi-rate data service users are distributed uniformly in each cell and the same spectrum is applied in both layers. In addition, we take into account the base station transmission power ratio between tiers and the relative position of microcell having island distribution in macrocell. The forward link interference is evaluated by using Monte-Carlo simulation introduced in [2]. In this paper, we compare the forward link erlang capacity of 1x system to 3x system and show that 3x system can increase the user capacity by 3.4 times in case of macrocell and microcell, respectively, compared to 1x system.
Wyner and Ziv considered the rate-distortion function for source coding with side information at the decoder (we call the Wyner-Ziv problem). In this paper we show an information-spectrum approach to the Wyner-Ziv problem for general class of nonstationary and/or nonergodic sources with side information at the decoder, where the distortion measure is arbitrary and may be nonadditive. We show that a general formula for the rate-distortion function of the Wyner-Ziv problem for general sources with the maximum distortion criterion under fixed-length coding by using the information spectrum approach.
Takashi OKUMA Takeshi KURATA Katsuhiko SAKAUE
In this paper, we describe a method for estimating external camera parameters in real time. We investigated the effectiveness of this method for annotating real scenes with 3-D virtual objects on a wearable computer. The proposed method enables determining known natural feature points of objects through multiplied color histogram matching and template matching. This external-camera-parameter calculation method consists of three algorithms for PnP problems, and it uses each algorithm selectively. We implemented an experimental system based on our method on a wearable vision system. This experimental system can annotate real objects with 3D virtual objects by using the proposed method. The system was implemented in order to enable effective annotation in a mixed-reality environment on a wearable computing system. The system consists of an ultra small CCD camera set at the user's eye, an ultra small display, and a computer. This computer uses the proposed method to determine the camera parameters. It then renders virtual objects based on the camera parameters and synthesizes images on a display. The system works at 10 frames per second.