Understanding Smart Sensors - Nomads.usp

354 Understanding Smart Sensorsdeterministic refers to the property of a signal that allows its future behaviorto be precisely predicteddieSee chipdiffusion a thermochemical process whereby controlled impurities areintroduced into the silicon to define the piezoresistor. Compared to ionimplantation, it has two major disadvantages: (1) The maximum impurity concentrationoccurs at the surface of the silicon, rendering it subject to surfacecontamination and making it nearly impossible to produce buried piezoresistors;and (2) control over impurity concentrations and levels is about one thousandtimes poorer than that obtained with ion implantation.digital output transducer output that represents the magnitude of themeasurand in the form of a series of discrete quantities coded in a system ofnotationdirect sequencefixed frequency spread spectrum techniquedissipation constant the ratio (in milliwatts per degree Celsius) at a specifiedambient temperature, of a change in power dissipation in a thermistor tothe resultant body temperature changeDoppler effect the change in the observed frequency of a wave caused by atime rate of change in the distance between the source and the point ofobservationDoppler radar radar that exploits the Doppler effect to measure the radialcomponent of the relative velocity between the radar system and the targetdown converterlower frequencya device that provides gain and frequency translation to adrift an undesired change in output over a period of time, with constantinput applieddynamic range the ratio of the largest to the smallest values of a range, oftenexpressed in decibelsembedded controlSee embedded systemembedded sensing the use of a sensor in a product for a secondary insteadof a primary function, for example, protection in a power deviceembedded system a system with one or more computational devices (whichmay be microprocessors or microcontrollers) that are not directly accessible tothe user of the system