| 摘要 |
The present invention relates to a fast, high precision, interference tolerant impedance measurement apparatus. The apparatus comprises an oscillator circuit having a characteristic frequency determined by the impedance to be measured. The oscillation voltage is converted by one or more high-gain limiting amplifiers to one or more square waves of the same characteristic frequency. The one or more square waves are down-divided by a frequency division circuit to a second square wave, and afterwards transfered to a time-to-digital converter which converts the period of said second square wave signal to a digital state. The digital state is fed to a digital processing unit, which may perform various functions like mapping the digital state to a digital number, filtering, rejection of scatter values, etc. Finally, a number is output from said digital processing unit which gives a measure for the value of the impedance to be measured.
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