CLOSED-LOOP INTERFEROMETRIC SENSOR USING LOOP GAIN FOR DETERMINING INTERFERENCE CONTRAST

摘要

In order to measure the contrast of interference in an interference-based, closed-loop, phase-modulating optical sensor device, the gain of the feedback loop in a feedback controller (12) is evaluated. This gain is found to be a measure for the contrast. The contrast evaluated in this way can e.g. be used for period-disambiguation when determining the measurand of the sensor device. The sensor device can e.g. be a high-voltage sensor or a current sensor.