Feldkamp, Joseph R.,Sullivan, Shawn J.,Heller, Jeffrey R.
申请号：
AU2007285409
公开号：
AU2007285409B2
申请日:
2007.07.20
申请国别(地区):
AU
年份:
2012
代理人:
摘要：
An oscillator provides a reference signal having a phase. A tunable reactivecircuit, including an induction coil, is driven by the fixed frequency referencesignal of the oscillator with coil adapted to be positioned adjacent the specimento generate an oscillating signal corresponding to the condition of the specimen.The tunable reactive circuit provides an output signal having a parameter indicativeof the condition of the specimen. A resonant control circuit compares the referencesignal to the oscillating signal and provides to the tunable reactive circuita resonance control signal representative of the comparison. The resonancecontrol signal tunes the tunable reactive circuit, which may be a series RLC circuit,so that the frequency of the oscillating signal is substantially constant.
