A novel ADPLL design using successive approximation frequency control

This paper presents a hardware implementation of a fully synthesizable, technology-independent clock generator. The design is based on an ADPLL architecture described in VHDL and characterized by a digital controlled oscillator with high frequency resolution and low jitter. Frequency control is done by using a robust regulation algorithm to allow a defined lock-in time of at most eight reference cycles. ASICs in CMOS AMS and UMC have been manufactured and tested. Measurements show competitive results to state-of-the-art mixed-signal implementations.     

Effect of manufacturing tolerances on dynamic equilibria of multibody systems undergoing prescribed rotational motion

A general formulation is developed for the tolerance analysis of dynamic equilibria in a multibody system undergoing prescribed rotational motion, with applications including robots, spacecraft, propulsion and power generation systems, and sensors and actuators. In a state of dynamic equilibrium, a subset of the generalized coordinates assumes constant values while the remaining coordinates vary and respond in time. Manufacturing tolerances can be mathematically represented by probabilistic distributions or statistical variables through either an analytical approach or a Monte Carlo simulation. In the present tolerance work, the tolerances of design parameters including lengths, stiffnesses, inertias, and attachment positions are examined. In order to analytically calculate the statistical response of the dynamic equilibrium positions to such tolerances, the first-order sensitivities of the equilibria with respect to parameters are calculated. To illustrate the method’s accuracy and computational efficiency, two numerical examples are considered, and the statistical results obtained analytically for the equilibria are compared with those calculated through Monte Carlo simulation. In some cases, an equilibrium configuration can have an operating condition for which the response has zero standard deviation to perturbations of a design parameter. That condition can be a useful design point to the extent that typical manufacturing tolerances or other sources of variation would have no effect on the dynamic equilibrium configuration.     

Joint maximum-likelihood parameter estimation for burst DSspread-spectrum transmission

We first derive the joint optimal maximum-likelihood (ML) estimator of the carrier phase, both Doppler shift and Doppler rate, and the spreading code delay for a short burst direct sequence/spread spectrum (DS/SS) transmission in the absence of the data modulation. The typical burst duration is three data bit periods (60 ms). The performance of the joint estimator is analytically derived separately for high and low carrier-to-noise ratio (CNR) values. A suboptimal ML estimator based on the method of averaged periodogram is proposed for the data modulation present case, allowing the joint estimation of the data bit values. Then the above parameters are assumed correctly estimated and a segmentation approach is adopted, deriving the optimal joint ML estimator for the bit synchronization epoch and data. Simulations show the joint estimators perform reliable down to a CNR of approximately 30 dB·Hz     

Bücherschau

Ohne Zusammenfassung VDI     

The pig caecum model: a suitable tool to study the intestinal metabolism of flavonoids

Pig caecum was used under anaerobic conditions to metabolize flavonoids from several classes, i.e., chrysin 1, naringenin 2, quercetin 3, and hesperetin 4. Whereas chrysin 1 was not converted by the pig intestinal flora under the experimental conditions used, naringenin 2 was transformed to 3-(4-hydroxyphenyl)-propionic acid and 3-phenylpropionic acid. Quercetin 3 was metabolized to phloroglucinol, 3,4-dihydroxyphenylacetic acid, and 3,4-dihydroxytoluene. Hesperetin 4 was degraded via eriodictyol to 3-(3-hydroxyphenyl)-propionic acid and phloroglucinol. Structural elucidation of the formed metabolites was performed by high-performance liquid chromatography--diode array detection (HPLC-DAD) as well as HPLC-electrospray ionization--mass spectrometry (ESI-MS (MS)) and high resolution gas chromatography-mass spectrometry (HRGC-MS) analyses. The time course of microbial conversion of 2-4 was determined by HPLC-DAD analysis, revealing slow degradation of 2 and rapid transformation of 3 and 4. The results lead to the conclusion that the pig caecum model is a suitable ex vivo model for studying the intestinal degradation of flavonoids.     

Limiter discriminator-detected GMSK with FM and GMSK interferencein a land mobile channel

This paper addresses Gaussian minimum-shift keyed (GMSK) receiver performance analysis for limiter discriminator detection with cochannel interference resulting from a combined cellular voice and packet radio network. A specific example is cellular digital packet data (CDPD), which shares spectrum with cellular voice users; thus, the CDPD receiver will see both narrow-band frequency modulation (NBFM) voice and GMSK data interference. Previous studies investigated the performance of a GMSK receiver with a single GMSK interferer and multipath delay. In this paper, we extend earlier work to multiple Rayleigh fading (Doppler spread) interferers having NBFM (f_dm=12 kHz) analog modulation and/or GMSK modulation. Probability of bit-error expressions are derived for the frequency modulation (FM) and GMSK interferer cases assuming medium-to-high signal-to-noise ratio regions. For scenarios of from one to six NBFM interferers, having the same total power, a corresponding Gaussian approximation is within 1.5 dB. Simulation results are also presented for various combinations of FM and GMSK interference. FM interference is only slightly worse than GMSK interference. Delay spread representing an urban scenario resulted in only a slight increase in the error floor     

纤维素纤维及其混纺机织物的连续前处理

描述了德国Zschimmer＆Schwarz公司开发的机织物前处理系统Optasize和Optasteam。，结果表明：用Optasize／Optasteam工艺可应用在日常生产中，并为定制加工提供解决方案以满足客户要求，其流程简洁经济而且可靠性高。通过采用这一工艺最初不同起因的织物质量差异可由此拉平。     

A Stripline-Implemented Baseband Signal Processor for Data and Clock Regeneration of PQM

A baseband signal processor for 1 Gbit/s pulse quaternary modulation (PQM), a pulse modulation format, has been developed and tested. A coupled stripline network is implemented for signal formatting, along with a frequency/phase tracking pulse demultiplexer which reduces predetection bandwidth and interpulse interference. Measured BER performance is presented along with computer simulation predictions.     

Potentialities of radio-occultation monitoring of the lower ionosphere on satellite-to-satellite paths

The data on the radio-occultation probing of the daytime ionosphere at altitudes of 70–130 km that are measured on satellite-to-satellite paths in subequatorial regions at latitudes of ±30° are analyzed. The dependence of regular variations in the integral electron concentration on the height of the ray line is discussed. It is shown that, at altitudes of 85–110 km, the height profile of electron concentration can be determined from the occultation data. The specific features of the variations in the radio-wave amplitude and in the integral electron concentration that are observed during the probing of sporadic ionospheric formations E _s are analyzed. Data on the frequency of occurrence of the E _s formations, their height, and the thickness of the layered structures are presented. The interfering effect of the ionospheric F region during determination of the parameters of the lower ionosphere is analyzed.