Power bus signal integrity improvement and EMI mitigation on multilayer high-speed digital PCBs with embedded capacitance

The continuous technology trend in the telecommunication market toward higher operating frequencies and high processing performances will give rise to new sophisticated chip sets, processors, and RF transceivers which will demand new feature to the PCB designs. As the complexity of the integrated circuits increases, signal integrity (SI) and electromagnetic compatibility (EMC) become key elements in the board design process. This paper analyzes the beneficial effects that a thin dielectric material between a pair of power and ground layers (embedded capacitance) has both in reducing power bus resonance amplitudes (SI approach) and radiated emissions (EMC approach) as well. Scattering parameter measurements carried out on the power bus of two production boards are presented and correlated with the electric field strength measurements conducted on the same boards in a semianechoic chamber.     

Analysis of output slave clock stability in SDH systems in terms of percentile MRTIE(τ)

The ‘maximum (relative) time interval error’ (MRTIE(τ)) is one of the parameters most used by international standardization bodies to characterize the stability of the clocks in modern SDH synchronization networks. Besides the original definition of MRTIE(τ), ITU-T has introduced a new MRTIE(τ) definition of percentile character. This new definition allows linking of the MRTIE(τ) parameter to the stochastic noise processes affecting the clocks in synchronization networks. In this paper, after a brief discussion about the original and percentile definitions of MRTIE(τ), the study focuses on the output stability of a slave clock based on a phase-locked loop (PLL) system. A PLL with internal phase noise sources and fixed bandwidth value is considered. The output slave clock stability is studied when there is a step change in the phase of the PLL reference signal. The need to consider the MRTIE(τ) parameter not only as a simple measure of wander (slow phase fluctuations) but also as a measure of fast phase fluctuations (jitter) on the clocks is emphasized, in spite of the latest ITU-T recommendations and ETSI standards. © 1998 John Wiley & Sons, Ltd.     

Ultralow Voltage Nanoelectronics Powered Directly, and Solely, From a Tree

Complex patterns of electrical potential differences exist across the structure of a tree. We have characterized these voltages, and measured values ranging from a few millivolts to a few hundred millivolts for Bigleaf maple trees. These potential differences provide a unique opportunity to power nanoelectronic circuits directly from a tree. We have designed, constructed, and successfully tested two ICs, powered solely through a connection to Bigleaf maple trees. The first circuit, built in a 130-nm technology, creates a stable 1.1 V supply from input voltages as low as 20 mV, and can be deployed to generate a usable voltage level for standard circuits. The second circuit, fabricated in 90-nm technology is a timer, operating at 0.045 Hz and can be used for time keeping in stand-alone sensor network nodes. The boost circuit and timer consume 10 and 2.5 nW of power during operation, respectively.      

Eye pattern evaluation in high-speed digital systems analysis byusing MTL modeling

A method for simulating the eye pattern of high-speed digital signals propagated on printed circuit boards using multiconductor transmission-line modeling is proposed in this paper. The approach takes into account the frequency-dependent properties of the dielectric materials of the board and of the conductors. The validation is performed by comparing the modeling with measurements taken from the literature, and directly performed on test boards specially design for this study     

Cardiac troponin T isoforms expressed in renal diseased skeletal muscle will not cause false-positive results by the second generation cardiac troponin T assay by Boehringer Mannheim

The purpose of this study was to determine whether the two monoclonal anti-cardiac troponin T (cTnT) antibodies (MAbs) used in the second generation cTnT assay by Boehringer Mannheim (BM, capture Ab, M11.7; detection Ab, M7) would detect cTnT isoforms expressed in human skeletal muscle in response to chronic renal disease (CRD). cTnT expression was examined in skeletal muscle biopsies obtained from 45 CRD patients, as well as nondiseased human heart (n = 3) and skeletal muscle (n = 3). cTnT proteins were resolved by modified 7.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with the following anti-cTnT MAbs: M11.7; M7; JS-2, Lakeland Biomedical; and 13-11, Duke University. All four antibodies detected the cTnT isoforms (Ta, Te) expressed in human myocardium. In 20 of 45 skeletal muscle biopsies, MAb M11.7 recognized its epitope in one to three proteins, molecular mass 34-36 kDa, designated Te, Td, and Tc; the strongest signal was that of Te. The same proteins were recognized by MAbs JS-2 and 13-11. The BM M7 antibody did not detect the cTnT isoforms in the molecular mass range of 34-36 kDa. However, MAb M7 did detect a cTnT isoform, molecular mass 39 kDa, in 2 of 45 biopsies. This isoform had an electrophoretic mobility similar to the predominant heart cTnT isoform, Ta. We conclude that cTnT isoforms are expressed in the skeletal muscle of CRD patients. However, given the epitopes recognized by the BM MAbs M7 and M11.7 and the variable presence of these cTnT isoforms in skeletal muscle, the second generation BM cTnT assay will not detect these isoforms if they are released from skeletal muscle into the circulation.     

Jitter performances of STM-16 line regenerator in SDH system

In the modern high-speed telecommunication networks on fiber optic (SDH standard), the long distance transmission links (e.g. a transoceanic transmission line) employ several cascaded regenerators. To ensure the synchronization of these networks, the jitter at each regenerator span has to be limited rigorously and maintained within permissible levels, according to ITU-T Recommendations and ETSI Standards. In this paper the architecture of an STM-16 line regenerator (bit rate equal to 2·48832 Gbits/s) is analyzed with particular consideration to the traffic timing characteristics. The influence of traffic timing blocks on jitter performances of the regenerator is investigated more in depth. © 1997 John Wiley & Sons, Ltd.     

Occurrence and survival of Campylobacter spp. in dairy matrices investigated by viability qPCR

The aim of this study was to investigate the survival of Campylobacter jejuni in dairy matrices by viability qPCR. Survival in UHT milk was examined first and the cheese outbreak strain, C. jejuni 11 218 showed enhanced tendency to become viable but nonculturable (VBNC). It survived for long at different pH values, in raw and fermented milk and cheese. Viability qPCR was also used to examine the occurrence of viable Campylobacter spp. in raw milk, detecting the bacteria in 40.9% of 25 mL samples negative on culture. Results showed that viability qPCR is valuable in estimating Campylobacter risk in dairy products.