一种高效宽带数字接收机设计技术

介绍了一种宽带数字接收机的设计技术,它结合多相滤波和一定条件下的电路等效关系,把抽取过程搬移到混频和滤波之前,从而可以高效地接收宽带信号.计算机仿真结果表明该技术是可行的.     

Measuring Market Orientation: Generalization and Synthesis

This paper reports on an integrative, cross-nationalstudy which synthesizes and retests work of three separate groupsof researchers who in the late 1980s developed measurementsof a firm's Market Orientation. The projects resulted in threedifferent but syntactically similar Market Orientation scaleswhich, along with other measures, were used to support substantiveconclusions, particularly those involving firm Performance. Basedon a new study of 82 managers in 27 European and U.S. companies,we show that all three scales are reliable and valid. The scalesalso seem to generalize well internationally, both in terms ofreliability and prediction of Performance. We also show thatthe scales are similar to one another in terms of various validitymeasures and in terms of correlations with Performance measures.Finally, we synthesize a 10-item scale based on a more parsimoniousdefinition of Market Orientation as: the set of cross-functionalprocesses and activities directed at creating and satisfyingcustomers through continuous needs-assessment.     

Schulleistungsunterschiede zwischen den deutschen Ländern

Since 2006 school achievement of German students has been measured on a regular basis within the so-called national educational monitoring. The most recent results show considerable differences between the states. At first glance, students in the eastern and southern states perform well while students in the city-states show poor results. This paper argues that these differences cannot be attributed to state-specific school policies. Rather, a large portion of the variance between the states can be explained by social and ethnical differences. As a consequence, not only educational policy but also social and integration policies have to be reviewed in order to get a better understanding of the differences in school achievement among the German states.     

Pecking order as a dynamic leverage theory

Static tradeoff theories, which do not explicitly treat the impact of transaction costs, do not explain the policy of asymmetry between frequent small debt transactions and infrequent large equity transactions. Nor do these theories explain why the debt ratio is allowed to wander a considerable distance from its alleged static optimum, or how much of a distance should be tolerated. We offer a class of diffusion models that mimic this behaviour in a stochastic-dynamic framework and are designed to optimize a financing strategy using any static tradeoff theory as input. The models developed reveal the determinants of the size and frequency of equity transactions and the range of values over which leverage variations are tolerated in four generic scenarios. They also yield a new formulation of the cost of capital that recognizes stochastic transaction costs and a penalty for deviation from any static-optimal leverage. Our class of models augments the pecking order theory, provides a flexible quantitative framework for its implementation as a decision tool, and facilitates the formulation of additional hypotheses for its empirical validation. Symmetrically, our results show the importance of dynamic factors in designing and interpreting empirical tests of static tradeoff theories. The results presented have important implications for the role played by static tradeoff theories in a stochastic-dynamic framework. One such implication is that the static-optimal leverage has no direct effect on the firm's leverage policy in this setting. The target leverage for refinancing transactions is different from the static-optimal leverage, and the mean leverage is generally different from both. As a consequence, the latter cannot be used to estimate the former. Another implication is that even when the mean leverage equals the static optimum, mean reversion is not an optimal behaviour and therefore not a legitimate test for the existence of a static tradeoff in a dynamic context. Still another implication is that wide variations in leverage ratios cannot be interpreted as evidence of leverage indifference. It follows that the pecking order theory is consistent with static tradeoff theories and does not require the assumption of leverage indifference.     

Do Monetary Unions Make Economic Sense? Evidence from the Scandinavian Currency Union, 1873–1913

Popular propositions as to what constitutes a successful single currency area are examined by looking at the Scandinavian Currency Union (1873–1913) formed by Denmark, Norway and Sweden. Applying a frequently used indicator of the desirability of monetary union, we study the symmetry of country-specific structural shocks (measured net of the non-Scandinavian influence) in these three countries. It is found that country-specific shocks are not highly symmetric. This conclusion is also supported by the absence of clear-cut differences between the pattern of structural shocks in Belgium and structural shocks in the Scandinavian countries. This suggests that the three Scandinavian countries did not form an optimum currency area during the period 1873–1913.
JEL classification : F 15; F 33; N 13