Analyzing the effect of the phase-jitter in the operation of second order phase-locked loops

Phase-locked loops (PLLs) are designed to extract timing signals in telecommunication networks. Noise, cross-talk, inter-symbol interference, quantization noise, and signal distortion are responsible for oscillations in the time between two successive transitions of the clock or data signal. It appears as an accidental phase modulation superposed to the original signal. This phenomenon is called timing jitter and affects the integrity of the data recovering process and, as a consequence, the error bit rate is increased. This problem has been studied by treating the jitter as a band limited noise process and tolerance masks for the jitter amplitude and frequency are recommended for several network architectures. Here, we develop a simple model with the continuous phase deviations of the clock signals considered as periodic signals in the band of the real disturbances. Comparisons with the stochastic approach are presented.     

An advanced laser application for controlling of electric resistivity of thick film resistors

When electric resistivity of Thick Film Resistor (TFR) is adjusted to the desired value, laser beam is irradiated onto the resistor material so that a part of the resistor material is instantaneously vaporized and cut away. This conventional laser trimming method to adjust the resistivity of TFRs is an indispensable technique for manufacturing elec-tronic devices such as hybrid ICs. A peculiar phenomena was revealed by us, that is, when specially selected pulse laser beams were irradiated to TFR, the TFR was surface modified without cutting grooves, and then resistivity of the TFR was decreased. We completed the advanced laser process to apply this peculiar phenomena. 8 By comparing with conventional trimming processes, we can show prominent features of the advanced process, for example, resistivity of fine size TFR (300 micrometers-width and under) can be easily controlled. The decrease in resistivity of the TFR is considered to result from the decrease in specific resistivity of glass in the TFR. Because it is considered that the glass in the TFR is heavily doped with ruthenium impurities during the surface modification due to results of morphology observations and x-ray diffraction analysis. We have applied this advanced laser process to fine size TFR (300 micrometers-width), and developed high density hybrid ICs.     

A copper/polyimide Metal-base packaging technology

A unique substrate MCPM (Mitsubishi Copper Polyimide Metal-base) technology has been developed by applying our basic copper/polyimide technology.¹ This new substrate technology MCPM is suited for a high-density, multi-layer, multi-chip, high-power module/package, such as used for a computer. The new MCPM was processed using a copper metal base (110 × 110 mm), full copper system (all layers) with 50-μm fine lines. As for pad metallizations for the IC assembly, we evaluated both Ni/Au for chip and wire ICs and solder for TAB ICs. The total number of assembled ICs is 25. To improve the thermal dispersion, copper thermal vias are simultaneously formed by electro-plating. This thermal via is located between the IC chip and copper metal base, and promotes heat dispersion. We employed one large thermal via (4.5 mm^?) and four small vias (1.0 mm^?) for each IC pad. The effect of thermal vias and/or base metal is simulated by a computer analysis and compared with an alumina base substrate. The results show that the thermal vias are effective at lowering the temperature difference between the IC and base substrate, and also lowering the temperature rise of the IC chip. We also evaluated the substrate’s reliability by adhesion test, pressure cooker test, etc.     

A 6-ns ECL 100 K I/O and 8-ns 3.3-V TTL I/O 4-Mb BiCMOS SRAM

The authors report a 4 M word×1 b/1 M word×4 b BiCMOS SRAM that can be metal mask programmed as either a 6-ns access time for an ECL 100 K I/O interface to an 8-ns access time for a 3.3-V TTL I/O interface. Die size is 18.87 mm×8.77 mm. Memory cell size is 5.8 μm×3.2 μm. In order to achieve such high-speed address access times the following technologies were developed: (1) a BiCMOS level converter that directly connects the ECL signal level to the CMOS level; (2) a high-speed BiCMOS circuit with low threshold voltage nMOSFETs; (3) a design method for determining the optimum number of decoder gate stages and the optimum size of gate transistors; (4) high-speed bipolar sensing circuits used at 3.3-V supply voltage; and (5) 0.55-μm BiCMOS process technology with a triple-well structure     

Unbiased InP detectors in the submillimetre wave region

High sensitivity unbiased detectors employing Ni-nInP Schottky-barrier diodes have been developed in a submillimetre-wave region. The voltage sensitivities of 120 V/W at 300 GHz and 17 V/W at 450 GHz were obtained, which are about three times higher than those of the usually used unbiased Si point contact diode detectors.     

10-GHz-spaced 1010-channel tandem AWG filter consisting of oneprimary and ten secondary AWGs

A very large channel-count arrayed waveguide grating (AWG) filter with more than 1000 channels is described. It was achieved by cascading a 1-THz-spaced flat-top 1×10 AWG as a primary filter and ten 10-GHz-spaced 1×160 AWGs as secondary filters in a tandem configuration. We achieved good adjacent and accumulated channel crosstalk values ranging from -32 to -25 dB and from -24 and -18 dB, respectively     

Memory LSI reliability

Large-scale integrated (LSI) memory circuit reliability is reviewed. Reliability of large-scale integrated memory circuits is discussed. The major physical mechanisms for failures in memory LSIs and measures to counter these failures are reviewed. Fault-tolerant techniques, divided into the spare row/column line substitution. (SLS) technique and the on-chip error-correcting code (ECC) technique, developed to overcome hard and soft failures are described. Design approaches for realizing high performance and high reliability are also discussed     

Involvement of brain serotonergic function in lidocaine-induced convulsions in mice

Influences of drug-induced manipulations of central serotonergic function on lidocaine- and pentylenetetrazol (PTZ)-induced convulsions were examined in mice. Agents that suppressed serotonergic transmission increased, whereas drugs that facilitated serotonin (5-HT) function decreased the incidence of lidocaine-induced convulsions. These treatments had similar influences on the incidence of PTZ-induced convulsions. Lidocaine (10(-5)-10(-3) M) reduced the stimulation evoked [3H]5-HT release from cortical slices, followed with an increased spontaneous [3H] overflow at higher concentrations. These results may suggest that brain 5-HT neurons are causally involved as inhibitory neurons in lidocaine-induced convulsions as in the case of PTZ-induced convulsions.     

Endothelin-1 secretion from cultured vascular endothelial cells of DOCA-salt hypertensive rats

The profile of endothelin-1 (ET-1) release from cultured vascular endothelial cells (ECs) obtained from deoxycorticosterone acetate (DOCA)-salt hypertensive rats, was examined and compared with that from normotensive sham rats. ET-1 release from ECs was increased in a time-dependent manner, and the level of DOCA-salt hypertensive rats was higher than that of sham rats. Incubation of ECs with transforming growth factor (TGF)-beta 1 or thrombin resulted in a significant increase in the ET-1 release, while FK409, a novel nitric oxide donor, produced a dose-dependent decrease in the release. In the case of ECs from DOCA-salt hypertensive rats, the potencies of TGF-beta 1- or thrombin-induced action was much less than that seen with sham rats, while the difference of reactivity to FK409 was not observed between ECs of DOCA-salt rats and sham rats. Thus, ET-1 production in ECs appears to be up-regulated in DOCA-salt hypertensive rats. In addition, there seems to be an abnormalities in the signaling pathway via TGF-beta 1- or thrombin-induced enhancement of ET-1 production in ECs of DOCA-salt hypertensive rats.     

Ectopic accumulation of 99mTc-HMDP in primary lung cancer in comparison with CT findings

Hypertension attributable to pheochromocytoma is a very attractive model for the elucidation of the pathogenesis of hypertension. Sixteen different point mutations in the RET proto-oncogene and 30 mutations in the Von Hippel-Lindau (VHL) tumor suppressor gene have been identified so far associated with expression of pheochromocytoma. Each of these mutations initiates either the syndrome of multiple endocrine neoplasia type 2 (MEN 2) (MEN 2A and MEN 2B) or the VHL disease. Certain mutations in both genes are associated with the presence of pheochromocytoma. In general, these pheochromocytomas produce catecholamines that result in hypertension. Therefore, analysis for germline mutations in these genes are of practical value, because susceptibility to these diseases can be predicted in as yet clinically unaffected relatives.