Test Port Research Articles

On-chip bugs for debug

The moment a chip arrives back from the fab is always tense. Once the first piece of silicon is down on the board and things check out electrically the thing to do is work out whether it really is an advanced system-on-chip (SoC) or a silicon-and-glass sandwich. Conceptually, the process is similar to the trace buffers used on many embedded processors. They do not capture actual instructions but record whether branches were taken or not. A debugger takes the data out through a test port and then uses it to reconstruct what happened inside the processor and display the instruction trace to the developer. With logic debug, the problem is more complex as there are so many different types of signal on the chip - not just a stream of instructions. But Novas's Siloti tool will use the recorded data in a similar way and attempt to show which signals changed during a given period.

A Novel Antiseptic-Microbial Barrier Cap for CVC Hubs or Injection Ports for Prevention of CVC-Related BSI

BACKGROUND: Patients with CVCs are at continuous risk of BSI caused by microorganisms that gain access through the hub or an injection port, particularly patients with long-term IVDs where infectious organisms most often gain access intraluminally. OBJECTIVE: We report a simulation study of a novel antiseptic cap (Saralex), which when threaded onto a luer-adaptable needleless injection port allows a chlorhexidine-impregnated sponge to come into continuous contact with the membranous surface of the port. Upon removal, there is no need to swab the membrane before accessing it with a needle or needleless connector. METHODS: One hundred five needleless IV systems of three types were tested. All contain a membrane and are accessible by a luer lock mechanism. Each test port was first heavily contaminated by dipping in a suspension of > 106 CFU/mL Enterococcus faecilis, then allowing it to dry. After 24 hours, 60 contaminated ports had the antiseptic cap threaded onto the port, removing it after 10 minutes; 30 ports were disinfected conventionally with a 70% isopropyl alcohol pledgett; and 15 were contaminated but not disinfected (positive control), before access. The contaminated test ports were then accessed with a sterile syringe containing 3mL of TSB and flushed; the flush solution was captured and cultured quantitatively. RESULTS: All 15 (100%) control ports which were not disinfected before entering showed massive microbial transmission across the membrane (4,500–10,000 CFU). Of the 30 ports accessed after conventional disinfection with an alcohol pledgett, 20 (67%) showed entry of microorganisms (442–25,000 CFU). In contrast, of 60 contaminated ports entered after application of the novel antiseptic cap for 10 minutes, only 1 (1.6%) showed any microbial transmission (P<0.001). CONCLUSIONS: This study shows that if the membranous septum of a needleless port is heavily contaminated, conventional disinfection with alcohol may not reliably prevent ingress of microorganisms and CVC–related BSI. In contrast, the antiseptic cap provides a high level of protection, even in the presence of heavy contamination. This novel technology deserves to be studied in a large multi-center clinical trial.

Influence of impedance mismatch effects on measurements of unloaded Q factors of transmission mode dielectric resonators

Precise measurements of the surface resistance of high temperature superconducting (HTS) thin films using transmission mode dielectric resonators requires accurate knowledge of the unloaded Q factor (Q/sub o/). So far, the most accurate method of Q/sub o/ determination for transmission mode resonators is the transmission mode Q factor (TMQF) technique based on the processing of S-parameters (S/sub 21/, S/sub 11/, S/sub 22/). The technique accounts for parasitic effects including noise, crosstalk, coupling reactance and coupling losses but does not yet take into account the impedance mismatch between the test ports of the vector network analyzer and the inputs to the resonator. Discrepancies between measured and ideal S-parameters due to the mismatch lead to inaccuracies in coupling coefficient computations. This causes undesirable error in the calculated Q/sub o/. We present measurements of Q/sub o/ obtained using the TMQF technique for mismatched and matched connections between the test ports of the vector network analyzer and the inputs to the dielectric resonator. These results are compared with values obtained using the traditional insertion loss method.

Two‐port calibration of test fixtures with different test ports

AbstractThe open‐short‐load (OSL) method is very simple and widely used for one‐port test fixture calibration. In this paper, this method is extended, for the first time, to the two‐port calibration of test fixtures with different test ports. The problem of phase uncertainty arising in this application has been solved. The comparison between our results and those obtained with the SOLT method shows that the method established is accurate for practical applications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 299–302, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10589

Estimating the noise mitigation effect of local decoupling in printed circuit boards

Local decoupling, i.e., placing decoupling capacitors sufficiently close to device power/ground pins in order to decrease the impedance of power bus at frequencies higher than the series resonant frequency, has been studied using a modeling approach, a hybrid lumped/distributed circuit model established and an expression to quantify the benefits of power bits noise mitigation due to local decoupling developed. In this work, a test board with a local decoupling capacitor was studied and the noise mitigation effect due to the capacitor placed adjacent to an input test port was measured. Closed-form expressions for self and mutual inductances of vias are developed, so that the noise mitigation effect can then be estimated using the previously developed expression. The difference between the estimates and measurements is approximately 1 dB, which demonstrates the application of these closed-form expressions in the PCB power bus designs. Shared-via decoupling, capacitors sharing vias with device power/ground pins, is also modeled as an extreme case of local decoupling.

Corn Production as Affected by Tillage System and Starter Fertilizer

Potential agronomic and soil conservation benefits of modified no‐till (NT) systems make them appealing for corn (Zea mays L.) production in the northern Corn Belt where adoption of NT has been limited due to yield reductions on these colder soils. A 4‐yr (1997–2000) experiment was conducted on a high P– and K–testing Port Byron silt loam (fine silty, mixed, mesic typic Hapludoll) to determine the effects of four tillage systems [no‐till (NT), Rawson zone till (ZT), fall strip till (ST), and conventional tillage practice (CT)] on corn production and cone index (CI; penetrometer resistance) in continuous corn and corn following soybean [Glycine max (L.) Merr.]. Eight treatments, four tillage systems (main plots) with starter fertilizer at rates of 0 and 168 kg ha−1 of a 9–10–24, were arranged in a split‐plot design with four replicates. Surface residue coverage after planting was maintained at high levels (&gt;40%) with NT, ZT, and ST, whereas coverage averaged only 25% with the CT practice. Cone index during the period of early plant growth was significantly less for the ZT and ST systems compared with the NT and CT systems, but CI did not exceed 1.3 MPa. Four‐year average yields of continuous corn grain ranked according to tillage were CT &gt; ZT = ST &gt; NT. A significant tillage × year interaction indicated equal yields for CT and NT in the first 2 yr but 1.0 to 1.2 Mg ha−1 less with NT in the last 2 yr. Tillage system did not significantly affect corn grain yields following soybean when averaged across years. Starter fertilizer increased yields by 0.5 Mg ha−1 on this high‐testing soil for all tillage systems in both crop rotations. Surface residue and corn yields following corn and soybean can be optimized using modified NT systems (ZT and ST) and starter fertilizer in these well‐drained, loess soils.

Corn Production as Affected by Tillage System and Starter Fertilizer

Potential agronomic and soil conservation benefits of modified no-till (NT) systems make them appealing for corn (Zea mays L.) production in the northern Corn Belt where adoption of NT has been limited due to yield reductions on these colder soils. A 4-yr (1997–2000) experiment was conducted on a high P– and K–testing Port Byron silt loam (fine silty, mixed, mesic typic Hapludoll) to determine the effects of four tillage systems [no-till (NT), Rawson zone till (ZT), fall strip till (ST), and conventional tillage practice (CT)] on corn production and cone index (CI; penetrometer resistance) in continuous corn and corn following soybean [Glycine max (L.) Merr.]. Eight treatments, four tillage systems (main plots) with starter fertilizer at rates of 0 and 168 kg ha−1 of a 9–10–24, were arranged in a split-plot design with four replicates. Surface residue coverage after planting was maintained at high levels (>40%) with NT, ZT, and ST, whereas coverage averaged only 25% with the CT practice. Cone index during the period of early plant growth was significantly less for the ZT and ST systems compared with the NT and CT systems, but CI did not exceed 1.3 MPa. Four-year average yields of continuous corn grain ranked according to tillage were CT > ZT = ST > NT. A significant tillage × year interaction indicated equal yields for CT and NT in the first 2 yr but 1.0 to 1.2 Mg ha−1 less with NT in the last 2 yr. Tillage system did not significantly affect corn grain yields following soybean when averaged across years. Starter fertilizer increased yields by 0.5 Mg ha−1 on this high-testing soil for all tillage systems in both crop rotations. Surface residue and corn yields following corn and soybean can be optimized using modified NT systems (ZT and ST) and starter fertilizer in these well-drained, loess soils.

Comparison between the ripple technique and the direct calibration method for characterisation of directional devices

A comparison between two different methods for measurement of directivity and test port match of directional couplers and bridges is presented. One of them, the popular ripple technique, is scalar. The other method, the so-called direct calibration method as derived by Juroshek (1997), with slight differences for the simultaneous measurement of both parameters, is vectorial. The two methods make use of a vector network analyser (VNA) and the calibrations performed are verified against known standards. The uncertainty associated with both techniques is computed.

Accuracy of hemodialysis modeling

One- and two-compartmental models of hemodialysis (HD) are well known. These models make it possible to analyze the course of treatment and to predict the effect of dialysis procedures. Mathematical modeling helps physicians to match dialysis therapy to the individual needs of the patient; however, the efficiency of the models depends on the accuracy of the coefficients. How to select coefficients in the case of one-compartmental models is known for urea and creatinine. Less information is available for two-compartmental models. Results on modeling of uric acid concentrations have not been published. The identification of the mathematical model coefficients was based on the concentration measurements of three markers of uremic toxicity (urea, creatinine, and uric acid) in both patients' blood and dialysate. Blood samples were taken from the arterial line several times throughout the dialysis period. Simultaneously, dialysate samples were taken from a test port in the dialyzer outflow line. The mathematical model parameters were determined so as to minimize the deviations between the measured points and the calculated curves. In this way, distribution volumes, cellular clearances, and dialyzer mass transfer coefficients were estimated. For a one-compartmental model, the median value of distribution volume V = 0.56 DW was obtained, where DW is the patient's dry weight. For a two-compartmental model, intercompartment volume Vi = 0.36 DW and extracompartment volume Ve = 0.21 DW. The following median values for cellular clearances were established: urea 415 (mL/min), creatinine 207 (mL/min), and uric acid 257 (mL/min). One- and two-compartmental models describe the concentration of the urea, creatinine, and uric acid very effectively, in contrast with phosphorus, in which modeling results are not satisfactory. Although two-compartmental models are more effective, they are much more complicated than one-compartmental models, which justifies using the one-compartmental model for hemodialysis modeling. A two-compartmental model must be used in the case of rebound phenomenon modeling. The total body water values we have obtained are similar to the anthropometrically based values for urea and creatinine and to a lesser degree for uric acid. Distribution volumes for one- and two-compartmental models obtained from patient weight are the simplest coefficients for mathematical models and have sufficient precision as well. The global value of both compartments is slightly greater than the corresponding value for a one-compartmental model. The effectiveness of dialyzers is in practice lower than might be expected on the basis of the data provided by their manufacturers. Urea cellular clearance is two times greater than creatinine and uric acid cellular clearances. The clearance differences are more prominent for the cellular membrane than for artificial semipermeable membranes.

An adaptive high power vector network analyzer for the tuning of NDB transmitter antennas

Reliable impedance measurements of installed HF air navigation antennas are possible with an automatically adjusted high power analyzer using levels above 30 dBm to overcome external interference signals coupled from the environment. Even a bad mismatch of an unknown device cannot cause unpredictable results or test equipment failures if this straightforward method is applied. The proposed adaptive network analyzer covers frequencies between 100 kHz-50 MHz and regulates the test port power down to 10 dBm according to the return loss and, thus, reduces the risk of damage and, at the same time, improves resolution at the other end of the return loss scale above 25 dB. The rejection of the misleading effects of unwanted signals can be further improved by the built-in modulation.

Synchronizing the IEEE 1149.1 test access port for chip level testability

IEEE STD 1149.9 is a widely accepted testability standard in the industry. Although its mandatory provisions focus narrowly on board level assembly verification testing, primarily via the boundary-scan register, its test access port (TAP) and many optional provisions make the standard usable for a much broader range of applications. Since its inception, numerous extensions and applications have been proposed that allow the standard's TAP to be used at the system level for general system-level test and maintenance tasks and at the chip level for accessing chip-level testability features. Chip-level applications thus far have used the port for accessing the chip's scan design or for simple triggering of on-chip built-in self-test features via the RUNBIST instruction. Applications requiring general access to chipwide testability features that operate at the full chip-clock rate have been rare, primarily because of one of the standard's basic tenets-namely, its dedicated test clock. This strategy enhances the test port to let it operate with two clocks. One is used while accessing IEEE 1149.1-compliant features, the other while accessing chip manufacturing test features.

Behavioural and electrophysiological responses of the phlebotomine sandfly Lutzomyia longipalpis (Diptera: Psychodidae) when exposed to canid host odour kairomones

SummaryCompounds from the odour‐producing glands of the fox Vulpes vulpes were collected. This complex mixture of compounds was used to stimulate the ‘ascoid’ olfactory organs of female sandflies in single sensillum and gas chromatography‐linked single sensillum recordings. Sixteen of these compounds were identified using gas chromatography‐linked mass spectrometry and amounts present were determined. The compounds fell into four organic classes: ketones, carboxylic acids, alcohols and aldehydes. Specific neurones present in the ascoid sensillum that responded to each of these classes of compound were characterized.A bioassay chamber was developed that gave female sandflies the choice of two odour sources. Female sandflies were attracted upwind by fox odour and were trapped in closer proximity to the fox odour port than the control port. Synthetic compounds were recombined in appropriate quantities to mimic the fox odour. In this bioassay, the synthetic blend attracted sandflies upwind, and again they were caught closer to the test port than the control port. Furthermore, the synthetic fox odour induced an electrophysiological response from neurones in the ascoid sensillum that was very similar to that induced by natural fox odour. No synthetic compound alone induced the same behavioural response from sandflies as did whole fox odour. However, benzaldehyde, 4‐hydroxy‐4‐methyl‐2‐pentanone and 4‐methyl‐2‐pentanone alone did cause sandflies to fly upwind and to be caught closer to the test port than the control.

Implementation and calibration of a two-port electrooptic network analyzer

A novel bidirectional electrooptic network analyzer has been demonstrated which enables the full S-parameter characterization of both electrooptic (E/O) and optoelectronic (O/E) components using a single connection of the device-under-test to the test ports. A combined two-tier E/O and O/E calibration is proposed. Measurement results which validate both the analyzer architecture and the calibration are presented.

Accurate power supply and ground plane pair models [for MCMs

In this paper, we derive a theory and method for the use of two-dimensional (2-D) discrete transmission lines (TL's) or discrete coupled transmission lines (CTL's) in modeling power supply and ground planes accurately. If the stray coupling between power or local ground and global ground is not significant, the discrete TL's model is used. Otherwise the discrete CTL's model is used. An arbitrarily shaped plane pair is discretized into a 2-D TL or CTL array by an automatic mesh algorithm. The equivalent distributed circuit, including skin loss effect at high frequencies, represents this power ground plane pair. The theory is extended to be applicable to a generic multiple dielectric layer structure. The model computation results are in excellent agreement with S parameter measurements for practical frequency ranges, including the first major resonant nulls and peaks. The null or peak of the S parameter frequency response represents the test port interaction with the resonant standing wave of these planes at that frequency. The resultant S parameter data of these models can be condensed into a simpler N port equivalent circuit to represent a larger hierarchical power and ground plane network for fast simulation.

Development of the EU water-cooled Pb-17Li blanket

The reference concept of the EU water-cooled Pb-17Li DEMO blanket is essentially formed by a directly-cooled steel box having the function of Pb-17Li container and by a double-wall U-tube bundle, immersed in the liquid metal, in which the pressurised water-coolant flows. The structural material is martensitic steel. All blanket performances satisfy DEMO requirements, such as tritium breeding self-sufficiency, capability of the box-structures to withstand water-coolant pressure under faulted conditions, limitation of the Pb-17Li/steel interface temperature to 480°C, power conversion efficiency of about 35%, and acceptable increase of temperature in case of out-of-vessel LOCA. A preliminary design of the test module and of the associated circuit components to be tested in ITER has been performed taking into account ITER specifications for test ports and ITER pulsed working conditions. Test-module DEMO-relevance has been one of the leading criteria for the module design. Preliminary module manufacturing sequences have been defined. The paper recalls the associated R and D activities which have to be finalised prior to the ITER testing and mainly involve tritium permeation barrier development, tritium extraction from Pb-17Li, advanced manufacturing techniques, definition of water/Pb-17Li interaction counter-measures, and Li-concentration control techniques.

Development and Evaluation of an Inhalable Bioaerosol Manifold Sampler

This paper describes the development and evaluation of an inhalable bioaerosol manifold sampler for the collection of replicate samples over sequential sampling periods. Wind tunnel experiments at wind velocities ≤0.6 m/sec (≤~120 ft/min) and at a sampling velocity of 0.6 m/sec yielded sampling efficiencies within 10% of the American Conference of Governmental Industrial Hygienists' inhalable curve up to particle diameters of about 18 urn and efficiencies within 18% for diameters up to 26 urn. At wind velocities ≥0.6 m/sec, a sampling velocity of 0.8 m/sec yielded efficiencies that were within 15% of the inhalable curve up to diameters of about 22 μm and within 20% for diameters up to 25 μm. Microscopic counts of 15.6-μm and 25.6-μm monodisperse polystyrene beads aerosolized in the wind tunnel and collected with the manifold sampler yielded precise concentrations (pooled CV=9.0 and 5.3%, respectively) averaging 115% and 92%, respectively, of measurements with the APS Model 3310 aerodynamic particle sizer. Field tests in a cotton dust environment demonstrated the ability to generate a time/concentration profile of fungal spores similar to that indicated for cotton dust levels determined with horizontal elutriators. Cotton dust was sampled efficiently while cotton fibers were excluded. Field tests on a dairy farm indicated no statistically significant bias (p=0.72) between spore concentrations determined with the manifold sampler and concentrations determined through a central test port.

Development and evaluation of an inhalable bioaerosol manifold sampler.

This paper describes the development and evaluation of an inhalable bioaerosol manifold sampler for the collection of replicate samples over sequential sampling periods. Wind tunnel experiments at wind velocities < or = 0.6 m/sec (< or = approximately 120 ft/min) and at a sampling velocity of 0.6 m/sec yielded sampling efficiencies within 10% of the American Conference of Governmental Industrial Hygienists' inhalable curve up to particle diameters of about 18 microns and efficiencies within 18% for diameters up to 26 microns. At wind velocities > or = 0.6 m/sec, a sampling velocity of 0.8 m/sec yielded efficiencies that were within 15% of the inhalable curve up to diameters of about 22 microns and within 20% for diameters up to 25 microns. Microscopic counts of 15.6-micron and 25.6-micron monodisperse polystyrene beads aerosolized in the wind tunnel and collected with the manifold sampler yielded precise concentrations (pooled CV = 9.0 and 5.3%, respectively) averaging 115% and 92%, respectively, of measurements with the APS Model 3310 aerodynamic particle sizer. Field tests in a cotton dust environment demonstrated the ability to generate a time/concentration profile of fungal spores similar to that indicated for cotton dust levels determined with horizontal elutriators. Cotton dust was sampled efficiently while cotton fibers were excluded. Field tests on a dairy farm indicated no statistically significant bias (p = 0.72) between spore concentrations determined with the manifold sampler and concentrations determined through a central test port.

US Demo Test Blankets in ITER

This paper summarizes the current status of the Demo blanket test systems and how the ITER reactor design and operations are being accommodated. The US blanket program is planning to develop a liquid metal breeder and a solid breeder blanket for testing and evaluation. The test blanket modules will have prototypical components, materials, and coolants representative of power reactor systems. The modules are to be located in the ITER horizontal test ports and installed/removed with special remote handling equipment. Adjacent ITER blanket neutronic and temperature conditions suggest the use of an isolation frame surrounding the test blanket modules or submodules. This frame will also provide additional shielding to protect the adjacent vacuum vessel. The frame and blanket module are attached to the surrounding backplate to transfer static and dynamic loads. All coolants and tritium-bearing fluids will be routed out of the midplane port to special heat exchangers and tritium separation systems. Special remote handling equipment is being designed to install and extract the test blanket modules. Dedicated transporters will be used to move the blanket and shielding modules to dedicated hot cells. Special facility areas will be provided immediately outside the port areas for the heat exchangers, pumps, and tritium-separationmore » systems. 1 ref., 6 figs.« less

Test stand for the Silicon Vertex Detector of the Collider Detector Facility

A test stand for the next generation of the Silicon Vertex Detector (SVX-II) of the Collider Detector Facility (CDF) at Fermilab has been developed. It is capable of performing cosmic ray, beam, and laser pulsing tests on silicon strip detectors using the new generation of SVX chips. The test stand is composed of a SGI workstation, a VME CPU, the Silicon Test Acquisition and Readout (STAR) board, the Test Fiber Interface Board (TFIB), and the Test Port Card (TPC). The STAR mediates between external stimuli for the different tests and produces appropriate high level commands which are sent to the TFIB. The TFIB, in conjunction with the TPC, translates these commands into the correct logic levels to control the SVX chips. The four modes of operation of the SVX chips are configuration, data acquisition, digitization, and data readout. The data read out from the SVX chips is transferred to the STAR. The STAR can then be accessed by the VME CPU and the SGI workstation for future analyses. The detailed description of this test stand will be given.

A broadband power meter calibration system in the frequency range from 10 MHz to 40 GHz using a coaxial calorimeter

A broadband power meter calibration system based on a newly constructed coaxial calorimeter has been developed in the frequency region 10 MHz-40 GHz. The RF power is measured as the difference of DC power supplied to the calorimeter built-in heater in the RF load, when RF is turned off and on, holding an isothermal control between the RF load and a temperature reference. To minimize the error due to the adiabatic coaxial waveguide, we devised a new method utilizing its output port as a test port. The evaluations showed a calibration uncertainty of (0.28-2.2)% expressed by one standard deviation at the 1 mW level in the full band.