Search

This paper describes two algorithms for generating test signals to efficiently test the linearity of ADCs. Linearity is an important testing item for ADCs, and it takes a long time (hence is costly) to test especially low-sampling-rate, high-resolution ADCs. We have proposed to generate a test signal consisting of multiple-sine waves, to precisely test the linearity for specific important codes (such as around the center of the output codes), using an arbitrary waveform generator (AWG) and an analog filter in our previous studies. Here, we formulate them for general use. Their verification is performed on a single sine wave, and good results are obtained to show the validity of the derivation algorithm.

In LSI testing, equivalent time sampling techniques are frequently used because the input signals to the device under test and the sampling clock are controllable; when the repetitive input signals are applied to the analog device under test, its output signals can be also repetitive. In this paper, we investigate an efficient waveform acquisition method with the equivalent-sampling using the metallic ratio of the sampling frequency and the input frequency, which is expected to be used for on-line, short-time and simple analog/RF/mixed-signal IC testing.

This article improves ADC sampling efficiency of the histogram method by investigating the ratio between the input saw frequency and the sampling frequency; the goal is to shorten ADC test time, and thus cost. Using a saw wave signal, the histogram RMS error within a certain range is simulated for the golden ratio, silver ratio, bronze ratio and prime number ratios. Golden ratio can halve the test time compared to the conventional method. We simulate an increase in output bins (the number of histogram bins), and find bronze ratio yields the best sampling efficiency.

Aqueous fluids are one of the principal agents of chemical transport in Earth´s interior. The precise determination of fluid fractions is essential to understand bulk physical properties, suc...

This paper proposes a summing node test method for the operational amplifier and shows the followings: (i) It can be used for parallel testing of multiple AC characteristics (such as open loop gain (AOL), PSRR and CMRR) of one operational amplifier simultaneously with the equivalent accuracy but much faster compared to the NULL method. Also it can measure them even for multiple operational amplifiers at the same time. (ii) It can measure THD, SNR and THD+N of the operational amplifier with the comparable accuracy to the audio analyzer usage case, by applying proper analog filters. In other words, it can measure them with remarkable accuracy at very low cost. These have been verified with simulations and experiments. The proposed summing node test method uses an inverting operational amplifier under test and its negative input is amplified by an auxiliary non-inverting operational amplifier. The input and power supply voltages for the operational amplifier under test are modulated by AC signals with different frequencies. The auxiliary amplifier output is digitized after analog filtering and FFT is performed to the digitized data. This proposed method can reduce operational amplifier test time with good accuracy but without expensive instruments at mass production shipping, to meet the requirements for IoT and automotive as well as audio applications.

This paper describes an accurate and fast testing technique for a precision voltage reference. Our proposed DC-AC conversion and FFT spectrum analysis method is applied and its experiment results show that measurement accuracy within ±100μV and measurement variation (repeatability) within ±10μV are feasible.

This paper introduces our production testing research results for analog and mixed-signal SoC in IoT era, such as operational amplifier, ADC, sampling circuit, timing related testing technologies. Notice that production testing and measurement / characterization for ICs are similar but different, and this paper introduces the former. The analog / mixed-signal testing plays a very important role in achieving both reliability and low cost for IoT and automotive systems. It also is a big technological challenge because there is no general method, but it requires state-of-the-art combination and optimization of a wide variety of technologies including circuit and system design as well as signal processing, control and measurement algorithms. Their overview including future technology challenges is described.

Fluid flow on different scales is of interest for several Earth science disciplines like petrophysics, hydrogeology and volcanology. To parameterize fluid flow in large-scale numerical simulations (e.g. groundwater and volcanic systems), flow properties on the microscale need to be considered. For this purpose experimental and numerical investigations of flow through porous media over a wide range of porosities are necessary. In the present study we sinter glass bead media with various porosities, representing shallow depth crustal sediments. The microstructure, namely effective porosity and effective specific surface, is investigated using image processing. We furthermore determine flow properties like hydraulic tortuosity and permeability using both experimental measurements and numerical simulations. By fitting microstructural and flow properties to porosity, we obtain a modified Kozeny-Carman equation for isotropic low-porosity media, that can be used to simulate permeability in large-scale numerical models. To verify the modified Kozeny-Carman equation we compare it to the numerically computed and experimentally measured permeability values.

This paper investigates the NULL method to apply for the mass production testing of the operational amplifier. The NULL method is widely used to measure the operational amplifier characteristics accurately at the laboratory level, but it takes relatively a long measurement time. Then, we have examined the operation of the NULL method circuit with simulations where the SPICE model provided by the vendor is used for the amplifier under test. Some experiments have been also performed to confirm the agreements to the simulation results. We have found that the proper selection of the compensation capacitor values in the NULL method circuit can lead to short-time and stable testing, which would yield its applicability to the mass production testing.

This paper describes an accurate and fast testing technique for small DC offset voltage of a high precision operational amplifier. Chopper techniques for DC-AC conversion and FFT spectrum analysis are combined and then accurate DC voltage measurement on the order of µV can be achieved. We have also investigated thermo-electromotive force effects and their countermeasures. Their simulations and experiments with prototype measurement systems have been carried out, and the measurement linearity up to as low as 0.2 µV of the DC measurement voltage was confirmed. We have also investigated its extension to multi-channel realization for short testing time.

The IP session highlights three innovative test practices in Japan, which include DC parametric test time reduction using digital controlled DC resource and deep reconsideration for ADC distortion testing as well as test time reduction of low sampling rate and high-resolution ADC linearity. These would be useful for automotive and IoT application device testing.

Silica-rich coatings of up to 660 μm thickness were found on the juvenile volcanic lapilli and blocks of the 1783 CE pyroclastic flow deposits 1.9–3.6 km northeast of the Maekake crater of Asama volcano in Central Japan. These coatings are composed of fine-grained volcanic ash particles with silica-rich cement. Raman spectroscopic measurements revealed that the interstitial silica-rich phase is hydrous amorphous silica and is considered to be a reaction product of ash particles with acidic volcanic rain and fog like volcanic smog (vog) as it has been recorded in Hawaii. The formation of amorphous silica without jarosite and the preferential alteration of plagioclase compared with pyroxene indicate that the reaction occurred with a sulfuric acid solution of pH

The dihedral angle (θ) between olivine and aqueous fluid is a critical parameter in identifying the grain-scale fluid connectivity which controls the distribution and migration of aqueous fluids in subduction zones besides physical properties of mantle wedges. Recent magnetotelluric observations have suggested the occurrence of significant fluid circulation in deep fore-arc regions, which can be explained by infiltration of saline fluid with a low θ in the mantle wedge ( Huang et al., 2019 ). Along with the salt component, non-polarized gas such as CO2, is a crucial constituent of subduction zone fluids. CO2 is known to increase the olivine–fluid θ under conditions in which the olivine does not react with CO2, which is in contrast to the effect of NaCl on θ. For a better understanding of the connectivity of multicomponent fluid in the mantle wedge, we experimentally constrained θ in olivine + H2O–CO2 fluid and olivine + H2O–CO2–NaCl (multicomponent) fluid systems at 1–4 GPa and 800–1100 °C. For the H2O–CO2 system, we found that CO2 tends to increase θ at 1 GPa and 800–1100 °C and at 2 GPa and 1100 °C. In contrast, CO2 reduced θ even below 60° at relatively high-pressure (P) and low-temperature (T) conditions, in which the olivine partly reacts with CO2 to form magnesite and orthopyroxene (opx). The consumption of non-wettable CO2 components in aqueous fluid alone cannot explain θ lower than those in a pure H2O system. Additional experiments on olivine–magnesite + H2O and olivine–opx + H2O systems showed that the presence of magnesite or opx decreased the olivine–fluid θ, which implies that coexisting minerals affect the olivine–fluid interfacial energy by changing the fluid chemistry. The results of the multicomponent system showed that the effect of NaCl on θ is much more significant than that of CO2. Strikingly, θ was smaller than 60° in all the magnesite- and opx-bearing multicomponent systems. Our results suggest that slab-derived fluid can infiltrate into the deep fore-arc mantle wedge through an interconnected network even in a CO2-bearing multicomponent system at pressures above 2 GPa, which facilitates significant fore-arc fluid circulation. The contrasting effects of aqueous fluid and silicate melt on the seismic wave velocity in a wide condition may allow for the possibility of mapping partial melt in the mantle wedge.

[Abstract] Directions and velocities of the motion of rain areas are estimated for each type of rain fronts, using time differences detected in the rain attenuation of the Ku-band satellite radio wave signals that have been measured at Osaka Electro-Communication University (OECU) in Neyagawa, Osaka, Research Institute of Sustainable Humanosphere (RISH) in Uji, Kyoto, and MU Observatory of Kyoto University in Shigaraki, Shiga, during four years since September 2002. These directions and velocities are shown to agree well with those manually obtained from the motion of rain fronts in the weather charts published by the Meteorological Agency. A numerical estimate of the effects of satellite diversity techniques indicates that between two locations among the three observation points (OECU, RISH, MU) separated by 20-50km, the joint cumulative time percentages of rain attenuation become lower as the two locations are aligned perpendicular to the rain front, in other words, along with the directions of the motion of rain areas.

Isothermal vapor-liquid equilibrium data of propylene oxide-ethylene and ethyl ether-ethylene systems were measured by a static method at 25°C and 40°C. The consistency of experimental results is examined by an enhancement factor of the vapor phase and by the Henry constant (f2/x2) of the liquid phase. By use of the Lewis fugacity rule for ethylene in the vapor phase, the activity coefficients of liquid phase and the fugacity coefficients of vapor phase are evaluated from themodynamic relationships. The P-x-y data of both systems are correlated with the Redlich-Kwong equation modified by Soave and the perturbation equation proposed by Gubbins and Twu. In the normal probability plot of the residuals, the SRK equation gives better correlation results for both systems.