This volume features the complete text of the material presented at the Nineteenth Annual Conference of the Cognitive Science Society. Papers have been loosely grouped by topic and an author index is provided in the back. As in previous years, the symposium included an interesting mixture of papers on many topics from researchers with diverse backgrounds and different goals, presenting a multifaceted view of cognitive science. In hopes of facilitating searches of this work, an electronic index on the Internet's World Wide Web is provided. Titles, authors, and summaries of all the papers published here have been placed in an online database which may be freely searched by anyone. You can reach the web site at: www-csli.stanford.edu/cogsci97.

With the advent of integrated circuits (IC), digital systems havebecome widely used in modern electronic devices, includingcommunications and measurement equipment. Direct Digital FrequencySynthesizers (DDS) are used in communications as transmitterexciters and local oscillators in receivers. The advantages aresuperior frequency stability, the same as that of the driving clockoscillator, and short switching times. The difficulties are loweroutput frequencies and rather large spurious signals. Compiled for practicing engineers who do not have theprerequisite of a specialist's knowledge in Direct DigitalFrequency Synthesizers (DDS), this collection of 40 importantreprinted papers and 9 never-before published contributionspresents a comprehensive introduction to DDS properties and a clearunderstanding of actual devices. The information in this volume canlead to easier computer simulations and improved designs. Featured topics include: * Discussion of principles and state of the art of wide-rangeDDS * Investigation of spurious signals in DDS * Combination of DDS with Phase Lock Loops (PLL) * Examination of phase and background 'noise' in DDS * Introduction to Digital to Analog Conversion (DAC) * Analysis of mathematics of quasiperiodic omission ofpulses DDFS can also serve as a textbook for students seeking essentialbackground theory.

This book is a printed edition of the Special Issue "Micro-Resonators: The Quest for Superior Performance" that was published in Micromachines