摘要 |
<p>An improved inductive reactance to frequency converter circuit (10) for producing an output signal whose frequency is capable of variation in response to a variable input inductance or inductive reactance (30) comprises differential gain means (42) and an improved resonant circuit (20) whose resonance frequency determines the frequency of the output signal. The improved resonant circuit (20) comprises a capacitance element (60, 62) and a transformer (64) whose primary coil (70) is capable of being connected to the variable inductive input reactance (30) and whose secondary coil (68) is connected in parallel with the capacitive element (60, 62) for enabling relatively small changes in the variable input inductive reactance (30) to be measured as relatively large changes in the resonance frequency of the resonant circuit (20).</p> |