传感器和传感器激励和测量技术.docxVIP

附录ATransducer and sensor excitation and measurement techniquesMany of todays industrial and instrumentation applications involving sensor. The function of the sensor system is to monitor changes, and then this data back to the main controller. For a simple voltage or current measurement sensors may be resistance in nature. However, some sensor system may be inductive or capacitive in nature, that is to say, the frequency range of the sensor resistance change is nonlinear. Impedance sensors such typical example is the proximity sensor - a campaign for the detection of the relative distance of objects; In addition, capacitive sensors or sensor sensibility - in the medical devices used to measure blood flow or blood pressure or blood qualitative analysis. In order to use these complex impedance sensors, the realization of measurement, to provide an exchange of (AC) excitation source frequency in the frequency range of the sensor for scanning. This article attempts to explain how the use of single-chip digital waveform generator to easily achieve this up to 10 MHz frequency scanning. Also introduced a kind of integrated incentive, response and digital signal processor (DSP) features a complete single-chip sensor solution that suited the requirements of up to nearly 50 kHz frequency applications. Sensors: working principle.Inspired by the frequency of sensor signals based on sensor values of L or C to show the corresponding instantaneous magnitude, frequency or phase changes. For example, the ultrasound will show a flow of phase offset, while the proximity sensor will cause the rate to change. Tracking changes in impedance that is the most commonly used to monitor the resonant frequency circuit. Capacitance value of the resonant frequency is equal to the frequency where the inductance value point. This is also the largest frequency curve frequency impedance value of the corresponding point. Under normal circumstances, for example, in static conditions, the sensor L, R an