Improved capacitance measurement by means of resonance locking
| Autor: | J Tapson, J R Greene |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Materials science
Electronic oscillator business.industry Dynamic range Applied Mathematics Hardware_PERFORMANCEANDRELIABILITY LC circuit Quantum LC circuit Capacitance Phase detector Voltage-controlled oscillator Hardware_GENERAL Control theory Hardware_INTEGRATEDCIRCUITS Optoelectronics business Instrumentation Engineering (miscellaneous) Voltage |
| Zdroj: | Measurement Science and Technology. 5:20-26 |
| ISSN: | 1361-6501 0957-0233 |
| DOI: | 10.1088/0957-0233/5/1/004 |
| Popis: | We describe a new LC method of capacitance measurement. The method consists of a synthesis of LC resonance and LC oscillator methods. The LC tank circuit is driven by a voltage-controlled oscillator (vco) and is included in an analogue phase-locked loop; the loop is designed to lock with no phase difference between current flow and driving voltage in the tank circuit. The system effectively tracks the resonance peak as the capacitance changes, thus allowing automatic measurement of capacitance by monitoring the vco input voltage or output frequency. The measurement bandwidth is dependent only on phase detector response, and can extend to the range of several MHz. The accuracy of this 'resonance locked loop' is equivalent to that of conventional systems and the dynamic range is considerably improved; a system with measured accuracy of 11 aF and bandwidth of 100 kHz has been constructed, and has been used to measure high-frequency submicrometre movements of piezoelectric actuators. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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