Patent ID: 7370535
Filing Date: 2008-05-13
Classification: G01L

Abstract:
1. A method of controlling operation of a state measuring apparatus comprising: synthesizing sensor oscillation signals having a frequency variable depending upon a state of an object to be inspected and reference oscillation signals together, to form beat signals having a beat frequency corresponding to a difference in frequencies between the sensor oscillation signals and the reference oscillation signals; measuring a period of the beat signals by counting count pulse signals in the period of the beat signals; and calculating a frequency of the sensor oscillation signals from a measured period of the beat signals and a period of the reference oscillation signals, and calculating a state value of the object from a calculated frequency of the sensor oscillation signals; wherein a frequency of the reference oscillation signals is varied, and the frequency of the sensor oscillation signals and the state value of the object are calculated based on the varied period of the reference oscillation signals.