Signal Wires Research Articles

Cryogen-Free Cryostat for Low Temperature Hundred Pixel Array Detectors

Enhancement of detection efficiency of low temperature detectors (LTDs) is quite important for biomolecular mass spectrometry. One solution to realize efficient analysing tools is to produce large-scale array detectors. In this case the wiring configuration in cryostats gets much more complex. For the purpose of detecting macromolecules efficiently, we are developing spectrometer systems with 100 pixel array superconducting tunnel junction detectors (STJs), infrared-blocking filters, and cryogen-free cryostats. Considering thermal leakage and signal attenuation through signal wires at each stage of a cryostat, the optimal combination of wiring cables and infrared-blocking filters was determined. Furthermore, from the point of view of cryostat handling, an easy exchange of detectors and simple maintenance are necessary for practical use of the spectrometers. In this study, the configuration of a cryogen-free cryostat and its cooling performance is presented.

Comprehensive Electromagnetic Modeling of On-Chip Switching Noise Generation and Coupling

A comprehensive modeling methodology is presented for the investigation of on-chip noise generation and coupling due to power switching. The backbone of the methodology is an electromagnetic model for the on-chip portion of the power grid. This allows for the impact of the displacement current density and, hence, electromagnetic retardation, to be taken into account in the accurate modeling of the power grid behavior at picosecond switching speeds. In this manner, and through the interfacing of this model with an electromagnetic model for the package portion of the power grid, which is described in terms of a multiport rational matrix transfer function, the impact of package-chip electrical interactions on switching noise can be modeled with electromagnetic accuracy. The electromagnetic model for the power grid is complemented by a resistance-capacitance model for the semiconductor substrate, which is capable of modeling local substrate induced noise coupling between neighboring circuits. Finally, distributed resistance, inductance, capacitance and conductance circuits for signal wires are extracted and used to provide for a transmission line-based modeling of crosstalk and power grid induced signal degradation. Transient simulations using the proposed comprehensive model are carried out using a hybrid time-domain integration scheme which combines a SPICE-like engine for the analysis of all circuit netlists and the nonlinear drivers incorporated in the model with a numerical integration algorithm suitable for the expedient update of the state variables in the discrete electromagnetic model for the power grid.

Reducing Interconnect Delay Uncertainty via Hybrid Polarity Repeater Insertion

Capacitive crosstalk between adjacent signal wires has significant effect on performance and delay uncertainty of point-to-point on-chip buses in deep submicrometer (DSM) VLSI technologies. We propose a hybrid polarity repeater insertion technique that combines inverting and non-inverting repeater insertion to achieve constant average effective coupling capacitance per wire transition for all possible switching patterns. Theoretical analysis shows the superiority of the proposed method in terms of performance and delay uncertainty compared to conventional and staggered repeater insertion methods. Simulations at the 90-nm node on semi-global METAL5 layer show around 25% reduction in worst case delay and around 86% delay uncertainty minimization compared to standard bus with optimal repeater configuration. The reduction in worst case capacitive coupling reduces peak energy which is a critical factor for thermal regulation and packaging. Isodelay comparisons with standard bus show that the proposed technique achieves considerable reduction in total buffers area, which in turn reduces average energy and peak current. Comparisons with staggered repeater which is one of the simplest and most effective crosstalk reduction techniques in the literature show that hybrid polarity repeater offers higher performance, less delay uncertainty, and reduced sensitivity to repeater placement variation.

Transition Skew Coding for Global On-Chip Interconnect

This paper presents new simulation results of the previously proposed transition skew coding (TSC) for global on-chip interconnects. Considering 2-GHz global clock frequency at the 90-nm node, we show that TSC can be applied to broad range of wire length on both semiglobal and global metal layers, while maintaining its energy efficiency and its advantages in terms of crosstalk reduction and signal integrity, and wiring and repeater area minimization.

Design of the Cryogen-Free Cryogenic System for the CUORE Experiment

The CUORE detector will be made of 988 TeO2 crystals and will need a base temperature lower than 10 mK in order to meet the performance specifications. To cool the CUORE detector a large cryogen-free cryostat with five pulse tubes and one specially designed high-power dilution refrigerator has been designed. The detector assembly has a total mass of about 1.5 ton and uses a vibration decoupling suspension system. Because of the stringent requirements regarding radioactivity, about 12 tons of lead shielding need to be cooled to 4 K and below, and only a limited number of construction materials are acceptable. The eight retractable radioactive sources for detector calibration and about 2600 signal wires add further complexity to the system. The many stringent and contrasting requirements together with the overall large size made the design of the CUORE cryogenic system a real mechanical and cryogenic engineering challenge. The cryogenic system is expected to be fully operational in the Gran Sasso Laboratory in July 2013. We report here about the current status of the cryogenic system construction, which has started about one year.

Soft tissue placement of implantable microphone

Provided herein are systems and methods where an implantable microphone of an implantable hearing system is positioned at a location spaced from the surface of the patient's skull. More specifically, the microphone is mounted to soft tissue of the patient to at least partially isolate the microphone from skull-borne vibrations. Accordingly, by utilizing a soft tissue mount, the microphone may be made more sensitive to ambient sounds with reduced concern to amplification of non-ambient vibrations caused by skull-borne vibrations including, for example, transducer feedback, talking and/or chewing. The system will further include an auditory stimulation device that is located proximate to the skull of the patient and which is operative to stimulate an auditory component of the patient in accordance with an output signal generated by the microphone. A subcutaneously routed signal wire may extend between the implanted microphone and the auditory stimulation device.

On optimal ordering of signals in parallel wire bundles

Optimal ordering and sizing of wires in a constrained-width interconnect bundle are studied in this paper. It is shown that among all possible orderings of signal wires, a monotonic order of the signals according to their effective driver resistance yields the smallest weighted average delay. Minimizing weighted average delay is a good approximation for MinMax delay optimization. Three variants of monotonic ordering are proven to be optimal, depending on the Miller coupling factors ( MCF) ratio between the signals at the sides of the bundle and that of the internal wires. The monotonic order property holds for a very broad range of VLSI circuit settings arising in common design practice. A simple, yet near-optimal, setting of wire widths within the bundle to yield the best average weighted delay is proposed. The theoretical results have been validated by numerical experiments on 65 nm process technology and industrial design data. In all cases the ordering optimization yielded improvement in the range of 10% in wire delay, translated to about 5% improvement in the clock cycle of a high-performance microprocessor implemented in that technology.

Simultaneous Shield and Buffer Insertion for Crosstalk Noise Reduction in Global Routing

As VLSI technologies scale down, interconnect performance is greatly affected by crosstalk noise due to the decreasing wire separation and increased wire aspect ratio, and crosstalk has become a major bottleneck for design closure. The effectiveness of traditional buffering and spacing techniques for noise reduction is constrained by the limited available resources on chip. In this paper, we present a method for incorporating crosstalk reduction criteria into global routing under a broad power supply network paradigm. This method utilizes power/ground wires as shields between signal wires to reduce capacitive coupling, while considering the constraints imposed by limited routing and buffering resources. An iterative procedure is employed to route signal wires, assign supply shields, and insert buffers so that both buffer/routing capacity and signal integrity goals are met. In each iteration, shield assignment and buffer insertion are considered simultaneously via a dynamic programming-like approach. Our noise calculations are based on Devgan's metric, and our work demonstrates, for the first time, that this metric shows good fidelity on average. An effective noise margin inflation technique is also proposed to compensate for the pessimism of Devgan's metric. Experimental results on testcases with up to about 10000 nets point towards an asymptotic runtime that increases linearly with the number of nets. Our algorithm achieves noise reduction improvements of up to 53% and 28%, respectively, compared to methods considering only buffer insertion or only shield insertion after buffer planning.

Development of Network Plug-in Actuator

We propose an intelligent connector (ICN) that uses a network plug-in actuator (NPA) or an intelligent connector (ICN) to reduce the number of signal and power cables and integrates an AC servomotor and motor drive with serial signal wires using a controller area Network (CAN). The ICN connects the NPA and a controller such as a personal computer and connects different networks such as the Ethernet, CAN, IEEE1394, or USB. We developed an NPA series from 5 W to 750 W and verified their functions. We also evaluated the ICN performance using the NPA. This system was installed on an “econovehicle” and its effectiveness was successfully demonstrated.

1P1-B10 近接覚から触覚までをシームレスにつなぐ汎触覚センサの開発(触覚と力覚)

A meshstructure tactile sensor series capable of attachment to freeform surfaces with reduced wiring is proposed. These wide purpose tactile sensor series sensing from proximity to contact seamlessly. The measuring principle of these sensors is the same. These sensors also feature high response speeds without requiring software processing. Regarding the wiring for multiple detection elements, internal connection is only required between adjacent detection elements. Also, sensor response speed is almost unaffected by the number, placement, or sensor surface area of the detection elements, and there are only 4 signal wires from the sensor.

Research and Development of Imaging Bolometers

An overview of the research and development of imaging bolometers giving a perspective on the applicability of this diagnostic to a fusion reactor is presented. Traditionally the total power lost from a high temperature, magnetically confined plasma through radiation and neutral particles has been measured using one dimensional arrays of resistive bolometers. The large number of signal wires associated with these resistive bolometers poses hazards not only at the vacuum interface, but also in the loss of electrical contacts that has been observed in the presence of fusion reactor levels of neutron flux. Imaging bolometers, on the other hand, use the infrared radiation from the absorbing metal foil to transfer the signal through the vacuum interface and out from behind a neutron shield. Recently a prototype imaging bolometer known as the InfraRed imaging Video Bolometer has been deployed on the JT-60U tokamak which demonstrates the ability of this diagnostic to operate in a reactor environment. The application of computed tomography demonstrates the ability of one imaging bolometer with a semi-tangential view to produce images of the plasma emissivity. In addition, new detector foil development promises to strengthen the foil and increase the sensitivity by an order of magnitude.

Acoustic emission from wire ropes during proof load and fatigue testing

The paper describes an experimental investigation into the enhancement of proof and fatigue testing procedures for wire ropes by incorporating data from acoustic transducer signals. During proof load tests on a selection of damaged wire ropes, it is shown that acoustic emission increases significantly after the damage is inflicted, even though ropes continue to pass the proof test. The relationship between acoustic emission signal characteristics and wire breaks is investigated and it is found that the most effective acoustic signal discriminators are energy and amplitude. Finally, the pattern of acoustic emission signals during a fatigue test is studied and a suggestion is made for a filtering technique to improve the recognition of imminent failure.

An ECO routing algorithm for eliminating coupling-capacitance violations

Engineering change order changes are almost inevitable in the late stages of a design process. Based on an existing design, incremental change is favored since it can avoid considerable efforts of redoing the whole process and can minimize the disturbance on the existing converged design. The coupling-capacitance violation elimination (CVE) problem is addressed. Due to the changes in the multiple layer routing design, the total coupling capacitance on some signal wire segments on a layer may be larger than their allowable bounds after postlayout timing/noise analysis. The target is to find a new routing solution without coupling-capacitance violations under certain constraints, which helps to keep the new design close to the original one. This paper proposes a two-stage algorithm to solve CVE problems, and present optimization strategies to speed up the execution. Experimental results demonstrate the efficiency and effectiveness of this algorithm

Study of a Mini-Ultrasonic Motor with Square Metal Bar and Piezoelectric Plate Hybrid

A new mini-ultrasonic motor with a metal bar and piezoelectric plate hybrid as a stator has been studied. Four piezoelectric plates are bonded to four sides of the metal bar. The metal bar is made of brass and the piezoelectric plates are made of Pb(Zr–Ti)O3. The polarization direction is vertical to the piezoelectric plate. Compared with the cylindrical type of motor, the motor with a square cross-section makes polarization more sufficient and the signal wire easier to be welded. In this study, the modal and harmonic analyses of the stator were performed by using the Finite Element Method. The resonance frequency of the motor is about 100 kHz, the no-load revolution is above 6000 rpm and the maximum torque is about 60 µN m. This new mini-ultrasonic motor has potential applications.

Alternate Self-Shielding for High-Speed and Reliable On-Chip Global Interconnect

SUMMARY In this paper, we propose alternate self shielding to remove critical transitions of on-chip global interconnect. Our proposed method alternates shield and signal wires cycle by cycle. The conventional self-shielding methods need additional wires to remove critical transition by encoding. The proposed alternate self-shielding, however, requires no additional wires. We evaluate our method by simulating signal transimission with a circuit simulator. As a result, our proposed method is superior in bit rate compared to others from 10% to 75%.

The precision tracker of the OPERA detector

The Precision Tracker of the muon spectrometer of the OPERA detector consists of ∼ 10000 aluminum drift tubes of 8 m length. They have an outer diameter of 38 mm and a wall thickness of 0.85 mm. The challenge of the detector design originates from the 8 m length of the drift tubes, a detector length, which has not been used before. Tight mechanical tolerances for positioning and alignment of the signal wires are required in order to make a significant measurement of the sign of the muon charge. The detector is manufactured in modules, which are 50 cm wide, each consisting of four adjacent drift tube planes. This guarantees high efficiency and complete rejection of the left–right ambiguity. The details of the novel mechanical design are described in this paper. For safety reasons, the drift tubes are operated with an Argon / CO 2 gas mixture. The gas volume of the drift tubes is entirely sealed with O-rings, in order to avoid ageing problems. The total gas volume amounts to about 80 m 3 . The front end electronics of the drift tubes consist of a bootstrap amplifier followed by a commercial ultrafast comparator. Thus only digital LVDS signals are transmitted over large distances. We report on the development and performance of the first two prototype modules of the precision tracker including test measurements of the resolution and efficiency obtained.

Optimization of superconducting microstrip interconnects for rapid single-flux-quantumcircuits

In this paper, issues related to the optimization of superconducting passive interconnectsare discussed. Results of the microwave optimization of bends, via connections andcrossings of superconducting microstrip lines (SMSLs) are reported. The optimum design ofthe SMSL cross gives more than 95% of transmission and can be well used in a two-buscross design with up to 14 signal wires. The results have been confirmed by time-domainsimulations and measurements.

Controlling Inductive Coupling in Wide Global Signal Busses Through Swizzling

Recent advances in Deep Submicron (DSM) design and manufacturing technologies have brought to the forefront the importance of inductive coupling amongst long interconnect in high performance microprocessors. Inductive coupling has been shown to depend directly on the overlap length between adjacent signal wires, the activity on these wires and the distance separating them. This paper presents a technique--known as swizzling--that exploits the inductive coupling dependence on distance to reduce the effect of any particular attacker on any of its victims. In the swizzling technique, the order of signal wires in global signal busses is continuously re-arranged to move attackers and victims away from each other. This paper shows that this technique significantly reduces the inductive coupling for the most vulnerable wires neighboring the attacker with zero area and routing resource penalty.

Non-uniform current distribution as the cause of false voltage signals in the ac lossmeasurement on a superconducting cable

Electrical measurement of ac loss in a short model of superconducting cable plays animportant role in the development of low-loss cables. The main problem in this type ofmeasurement is the appearance of false loss voltage signals. For the experiments when thetotal current splits into parallel paths, inevitably with different impedances, a voltagecomponent in phase with the cable current is induced in signal wires. The source of thisvoltage originates in the phase differences between the total current in the cable and thecurrents flowing through individual tapes. A simple equivalent circuit model has beendeveloped that allows us to estimate these phase shifts. Analytical formulae have alsobeen derived for the false voltage signals. According to these formulae reliabledata can be achieved by taking the sum of voltage signals read by signal wiressymmetrically surrounding the cable. While not contributing to the ac loss measurement,the false voltage signals can be used to detect the phase shifts in tape currentsreferred to the phase of the total cable current. Theoretical predictions have beenexperimentally verified with the help of a 1 m cable model manufactured to allow for thetheoretical model to be evaluated. Experiments demonstrated that the variation incontact resistances is the most critical factor in the testing of short cable models.

Efficient shield insertion for inductive noise reduction in nanometer technologies

With high clock frequencies, faster transistor rise/fall time, wider wires, and the use of Cu material interconnects, interconnect inductive noise is becoming an important design metric in digital circuits. An efficient technique to reduce the inductive noise of on-chip interconnects is to insert shields among signal wires. An efficient solution for the min-area shield insertion problem to satisfy given explicit noise bounds in multiple coupled nets is provided. The proposed algorithm determines the locations and number of shields needed to satisfy certain noise constraints. Experimental results show that the proposed approach minimizes the number of shields required to satisfy the noise constraints and uses less runtime than the best alternative reported approach.