蓝牙模块的测试方案

测试项目在蓝牙环境中，哪些方面需要测试？蓝牙模块包括连接到主机设备的无线电 (硬件)和堆栈 (软件)。协议是构成堆栈的一套代码，在生产车间中将不会测试协议。修订系统软件可能会改变硬件性能，但必须在设计集成阶段对其进行粼选。需要使用的一些重要参数，如误码率(BER)、功率电平等对功能进行测试。选择测试必需理解由于无线电的设计方式哪些内容可能会改变，并根据测试的项目查看其发挥的作用。它是否提供了独特的功能？没有提供哪些功能？如打印机使用的蓝牙链路。在技术得到验证前，打印机可能仍会通过电缆提供打印功能，因此测…     

Effect of series compensation on the voltage instability of EHV long lines

In this paper, the effects of the operating conditions and dynamic performance on the voltage instability phenomena of EHV lines with series compensation is discussed. Exponential modelling of loads and exact long-line equations are used in the analysis. Graphs showing the variations of the receiving-end voltage and the transformer tap ratio with time for an assumed load variation are given. It is shown that when series compensation is provided, the chances of voltage instability occurring are less. The effect of switched series compensation on the voltage instability is also investigated. The error in using short-line equations for the analysis of voltage instability phenomena is highlighted. The random loading conditions of the system and the random load parameter variations are also considered for the first time in analysing the voltage instability phenomenon.     

Effect of Sb, P, Sn and B on the microstructure and creep properties of normalized and tempered 1.25 Cr-0.5 Mo steels

A program to study the effect of Sb, P, Sn and B on creep properties of four normalized and tempered 1.25 Cr-0.5 Mo steels at 538°C (1000°F) has been completed. Results show that even a combined addition of large amounts of Sb, P and Sn does not affect short time creep strength or ductility of the steel at 538°C (1000°F). Addition of B resulted in an increase or decrease of creep strength depending on the nature of the impurity species present, presumably due to B-impurity interactions. Regardless of the effect on creep strength, B additions caused sharp reductions in rupture ductility in all cases. Comparison of the present results on the four laboratory steels (100 pct bainite) with results of a previous study on a commercial steel (60 pct bainite + 40 pct ferrite) show that the effect of microstructure becomes negligible and rupture strength values of the various steels at 538°C (1000°F) approach each other at rupture times in excess of 10⁴ h.     

Measurement of individual differences in preference for numerical information.

Develops and validates a measure of preference for numerical information, defined as a proclivity toward using numerical information and engaging in thinking involving numerical information, and assesses the relationship of this construct to several constructs. Although past research has focused on ability in using numerical information, a basic attitude or proclivity toward numerical information has not been isolated and studied. This construct is argued to have applications in settings that involve the use of numerical information and to be related to several interests, temperaments, and cognitive styles. A measure of preference for numerical information is developed and tested for reliability and validity, its relationship with several constructs is examined, and its applications in various settings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The CEO problem [multiterminal source coding]

We consider a new problem in multiterminal source coding motivated by the following decentralized communication/estimation task. A firm's Chief Executive Officer (CEO) is interested in the data sequence {X(t)} _t=1^∞ which cannot be observed directly, perhaps because it represents tactical decisions by a competing firm. The CEO deploys a team of L agents who observe independently corrupted versions of {X(t)}_t=1^∞. Because {X(t)} is only one among many pressing matters to which the CEO must attend, the combined data rate at which the agents may communicate information about their observations to the CEO is limited to, say, R bits per second. If the agents were permitted to confer and pool their data, then in the limit as L→∞ they usually would be able to smooth out their independent observation noises entirely. Then they could use their R bits per second to provide the CEO with a representation of {X(t)} with fidelity D(R), where D(·) is the distortion-rate function of {X(t)}. In particular, with such data pooling D can be made arbitrarily small if R exceeds the entropy rate H of {X(t)}. Suppose, however, that the agents are not permitted to convene, Agent i having to send data based solely on his own noisy observations {Y_i(t)}. We show that then there does not exist a finite value of R for which even infinitely many agents can make D arbitrarily small. Furthermore, in this isolated-agents case we determine the asymptotic behavior of the minimal error frequency in the limit as L and then R tend to infinity     

Dilatometric technique for evaluation of the kinetics of solid-state transformation of maraging steel

Solid-state transformation kinetics of a 350 grade commercial maraging steel were investigated using a nonisothermal dilatometric technique. Two solid-state reactions—namely, precipitation of intermetallic phases from supersaturated martensite and reversion of martensite to austenite—were identified. Determination was made of the temperatures at which the rates of these reactions reached a maximum at different heating rates. The kinetics of the individual reactions in terms of activation energy were analyzed by simplified procedures based on the Kissinger equation. An estimated activation energy of 145 ± 4 kJ/mol for the precipitation of intermetallic phases was in good agreement with reported results based on the isothermal hardness measurement technique. Martensite to austenite reversion was associated with an activation energy of 224 ± 4 kJ/mol, which is very close to the activation energy for diffusion of substitutional elements in ferrite. Results were supplemented with microstructural analysis.     

Diversity combining in FH/BFSK systems to combat partial bandjamming

A combiner for a frequency-hopped binary frequency-shift keyed (FH/BFSK) system, called the product-combining receiver (PCR), is introduced. The performance of the PCR is evaluated for the cases of an on/off partial-band noise with optimum-jamming fraction, and worst-case, partial-band tone jamming. The performance of PCR is shown to be comparable to that of the clipper receiver. The effect of diversity combining, along with convolutional coding and ratio-threshold technique, is analyzed. Whereas the clipper requires the knowledge of signal-to-noise ratio for threshold adjustments, the PCR does not require this knowledge for this operation     

Effects of humidity and temperature on in vitro dissolution of carbamazepine tablets

The rate and extent of dissolution of various approved marketed carbamazepine (CBZ) tablets exposed to 33, 52, 75, and 97% relative humidities at both room temperature and 40 degrees C, and saturated water vapor at room temperature were compared to fresh unstressed tablets. The dissolution data indicate that exposure of CBZ tablets to high humidity and temperature can have a profound effect on tablet disintegration and dissolution. The dissolution rates of some batches of CBZ products exposed to 97% humidity at 40 degrees C or saturated water vapor at room temperature were drastically reduced in only 6-7 days.     

Superconductivity in irradiated A-15 compounds at low fluences. I. Neutron-irradiated V3Si

The behavior of the superconducting transition temperature T _c of singlecrystal and polycrystalline V₃Si was investigated as a function of low-fluence neutron irradiation. It is found that the initial degradation of T _c is sample-dependent, some specimens showing no degradation in T _c up to a fluence of 2 × 10¹⁸ n/cm². This and many other earlier observations on low-fluence behavior are explained in terms of a recently proposed model of radiation damage in A-15 compounds.Work performed under the auspices of the U.S. Energy Research and Development Administration.