Digital-domain self-calibration technique for video-rate pipelineA/D converters using Gaussian white noise

A digital-domain self-calibration technique for video-rate pipeline A/D converters based on a Gaussian white noise input signal is presented. The proposed algorithm is simple and efficient. A design example is shown to illustrate that the overall linearity of a pipeline ADC can be highly improved using this technique     

Does solitary plasmacytoma still exist? Value of MRI of the spine

In order to differentiate benign from malignant pulmonary masses by means of observing blood flow signal, with coloured Doppler sonography, the authors examined 67 in-patients who had been found having masses in the lungs by X-ray or CT. For comparison 43 benign cases showing blood signals in the lung was also examined. The results showed that the blood flow signals of all lung cancers were of relatively low blood flow resistance or arteriovenous shunting, while those of benign lesions were of high blood flow resistance. The pulsatility index in lung cancer was 1.02 +/- 0.30, the restance index was 0.52 +/- 0.13, the peak systolic velocity was 0.19 +/- 0.11 m/s, the end diastolic velocity was 0.06 +/- 0.02 m/s. The pulsatility index in benign pulmonary lesions was 1.53 +/- 0.30, the resitance index was 0.86 +/- 0.05, the peak systolic velocity was 0.28 +/- 0.05 m/s and the end diastolic velocity was 0.04 +/- 0.01 m/s. There were significant differences between the benign and malignant pulmonary lesions in the four indices (P < 0.01) by t test and t' test. Lower pulsatility index, lower resistance index, lower peak systolic velocity and higher end diastolic velocity were characteristics of malignancy.     

Sixth-order differential Sallen-and-Key switched capacitor LPF using a-IGZO TFTs

This paper presents sixth-order fully differential active low pass RC and switched-capacitor (SC) filters using N-type IGZO thin-film transistors for flexible wearable continuous health monitoring systems. As a first step, a low-gain amplifier using a diode-connected load and a fully differential amplifier is designed with positive feedback based on capacitor bootstrapping. These amplifiers present a gain around 5.03 and 40 dB, respectively, whereas their respective GBW product are around 450 and 200 kHz. Then these amplifiers are employed to realize biquads, with which a sixth-order Sallen-Key low-pass RC and SC filters are implemented. The SC filter realized with low-gain DDA has shown a simulated THD of −30.9 dB, SFDR of 30.1 dB, and a power consumption of 456 μW. On the other hand, the SC filter presents a THD of −31.4 dB, SFDR of 32.2 dB, and a power consumption of 573 μW with high-gain differential difference amplifier (DDA) when a power supply of 10 V is used. Circuit simulations have been carried out in Cadence Virtuoso using in-house IGZO TFT models.     

A Cmos Interface for Thermocouples with Reference-Junction Compensation

This paper presents a CMOS interface for a thermocouple, includingreference-junction compensation. The interface contains a first-orderoscillator whose period is modulated by the signal from the thermocouple(V_X) and two other signals generated internally. One is abase-emitter voltage (V_BE) and the other is a PTAT voltage(V_PTAT). Linear combinations of the periods corresponding tothese two voltages are made by a µC, to obtain a reference signal anda temperature-dependent signal. The internal signals are required to provideauto-calibration for offset and gain and to measure the interface internaltemperature. Dynamic Element Matching is applied to generate an accurate andreliable PTAT voltage. The inaccuracy in the base-emitter voltage iscalibrated using a vertical PNP substrate transistor with multi-emitterareas. The applied modulator used in the circuit has a second-orderfiltering which suppresses low-frequency (1/f) noise. This filteringproperty enables the use of a low-cost CMOS process for the implementationof the circuit. The interface is able to measure a voltage(V_X) in the range of –27 mV to 100 mV, the measuredaccuracy of the system over a temperature range of –25°C to75°C is 550 ppm of V_X ± 2µV. The inaccuracyin determining the reference-junction temperature is 0.6 K. The measuringtime is 50 ms.     

Evaluation of the aging of elastomeric acrylonitrile-butadiene rubber and ethylene-propylene-diene monomer gaskets used to seal plates heat exchanger

Acrylonitrile-butadiene rubber (NBR) and ethylene-propylene-diene monomer (EPDM) gaskets are used as seals in plates heat exchangers due to their elasticity and resilience. However, contact with fluids, oxygen, ozone, and heat lead to permanent deformation. This study investigates the degradation of gaskets submitted to similar service conditions: compressed in a groove for up to 360 h at 100 and 120°C. The analysis was carried through compression set (CS), compression stress relaxation, surface morphology, Shore A hardness, indentation modulus profile, crosslink density, and Fourier transform infrared region with attenuated total reflection analysis. For EPDM, in thermo-oxidative aging there is a counterbalance between chain scission and crosslinking, which increases CS while hardness and crosslink density remain low. For NBR, diffusion-limited oxidation causes heterogeneous oxidation, creating a crosslinking network near the surface. The values for CS, Shore A hardness, and crosslink density raised to 50%, 10%, and 75%, respectively. Furthermore, the side thermo-oxidation was reduced due to the presence of the groove, which reduces oxygen access. Using FITR analysis, a thermo-oxidative interaction mechanism was proposed for the EPDM and NBR gaskets. It was concluded that EPDM presented a more reliable behavior for the gasket and seal applications under the analyzed conditions.     

Advanced low viscosity synthetic passenger vehicle engine oils

Premium quality synthetic passenger vehicle engine oils have been marketed by the authors' company since the early 1970s. During this time, the performance benefits of synthetic-based engine oils have been documented in a wide variety of engine and vehicle tests. The purpose of this paper is to demonstrate that, with the use of synthetic base oils and advanced additive technology, low viscosity oils can be formulated that have high fuel efficiency but which retain superior engine protection and performance reserves. Specifically, two synthetic engine oils, an SAE OW–40 and an SAE OW–30, have been developed that exceed the highest industry standards in both US (AP1)and European (ACEA) fuel economy and durability engine tests. The high quality of this technology is demonstrated in industry-standard engine and laboratory performance tests, as well as non-standard tests, such as extended-length engine tests, vehicle fuel economy tests, high mileage chassis rolls tests, and extended oil drain ‘over-the-road’ vehicle tests.     

Positive-negative DC-DC converter using amorphous-InGaZnO TFTs

This paper presents two DC-DC converters capable of generating either positive or negative output DC voltage using amorphous-indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs). While one uses conventional diode-connected cross-coupled (design-1), the other employs a bootstrapped cross-coupled (design-2) DC-DC converter, which overcomes the limitations of design-1 but requires boosted clock pulses. Therefore, an on-chip clock booster is proposed to generate all the required signals without any external clock pulses. The performance of the proposed circuits (DC-DC converters and clock booster) has been demonstrated using in-house a-IGZO TFT models in the Cadence environment. The simulation results have shown that design-1 (design-2) generates negative or positive output DC voltage of 7.25 V (7.8 V) or 12.7 V (15.2 V), respectively, for a supply voltage of 8 V, using a single DC-DC converter. Therefore, the output DC voltage of design-2 is close to the theoretical value, and it ensures robust performance against different load currents when compared with design-1. Besides, design-2 has shown a maximum power efficiency of 90%, superior compared with design-1, where power efficiency is 60.7%. Therefore, this circuit finds potential applications in the next generation flexible displays.     

A 6.2 mW 0.024 mm2 fully-passive RF downconverter with 12 dB gain enhancement using MOS parametric amplification

This paper describes a fully-passive discrete-time switched-capacitor RF downconverter with an on-chip oscillator, that combines quadrature mixing and harmonic rejection, designed in a 130 nm digital CMOS technology. By using MOS capacitors (varactors) to perform parametric amplification, it is possible to achieve a measured gain enhancement of about 12 dB, together with 21 dB noise figure and more than 5 dBm IIP3. Operating in the VHF-III band, the downconverter core dissipates 6.2 mW and occupies 0.024 mm².     

A simple accurate bridge-transducer interface with continuousautocalibration

This paper presents a one-chip simple and accurate transducer interface for resistive bridges. A key part of this interface is formed by a novel dynamic voltage divider. In this divider the bridge supply voltage is measured for reference purposes in small parts (piece-wise measurement) which are within the range of the bridge output voltage. The use of an autocalibration technique, the three-signal method, eliminates influeuce of linear parameters and errors. Moreover, the effects of the nonidealities of the applied switches are also eliminated. The circuit has been realized in a 3 μm BiCMOS process and shows an uncertainty of only 10 μV for a bridge supply voltage of 5 V