Method and apparatus for discriminatively determining electrical constants
AssigneeShionogi & Co., Ltd.
InventorsYoshikazu Hoshino, Masayoshi Shuto
Life of this patent
Estimating the term…
Abstract
An apparatus and method for determining electrical characteristics of an object wherein the phase difference between an input signal to and an output signal from a measuring circuit containing the object is maintained constant. Properties of the object are determined by monitoring the output of the measuring circuit of an amplitude signal related to the resistance of the object and by monitoring the output of the measuring circuit for an amplitude signal and a frequency signal related to the reactive impedance of the object.
Claims20
A method for discriminatively determining electrical characteristics of an object, said characteristics including a resistive part, a capacitive part, and an inductive part, and said object being within a detection cell of a measuring unit circuit, comprising the steps of:
- maintaining a constant phase difference between the phase of an input signal to said measuring unit circuit and the phase of an output signal of said measuring unit circuit corresponding to the phase angle in a frequency transfer function of said measuring unit circuit;
- determining a value corresponding to said resistive part in accordance with an amplitude quantity corresponding to the amplitude of the output of said measuring unit circuit, said amplitude quantity being proportional to the resistance of said object;
- determining a value independent of said resistive part corresponding to one of other possible characteristics of said measuring unit circuit, said other possible characteristics being said capacitive part and said inductive part, in accordance with said amplitude quantity and a frequency quantity corresponding to the frequency of any one of the input and output signals of said measuring unit circuit, the respective frequencies of the input signal to said measuring unit circuit and the output signal of said measuring unit circuit being equal.
An apparatus for discriminatively determining electrical characteristics of an object, said characteristics including a resistive part, a capacitive part, and an inductive part, comprising:
- a constant value control loop for maintaining a phase angle in a frequency transfer function at a predetermined value, said constant value control loop comprising:
- a measuring unit circuit having said frequency transfer function for application to an input signal thereof to obtain an output signal thereof, said object being within a detection cell of said measuring unit circuit;
- detector means for detecting a phase difference between the output signal of said measuring unit circuit and the input signal to said measuring unit circuit and for obtaining a phase difference signal in accordance with said phase difference;
- and
- a voltage controlled oscillator for obtaining an output signal having a frequency determined in accordance with said phase difference signal, the signal obtained by said voltage controlled oscillator being supplied to said measuring unit circuit as the input signal thereof;
- and a signal processing circuit for selectively obtaining signals corresponding to the respective values of said electrical characteristics, comprising:
- a pulse generator for obtaining a pulse signal having a frequency corresponding to the amplitude of the output signal of said measuring unit circuit, the amplitude of the output signal of said measuring unit circuit being proportional to said resistive part, and
- counter means for counting said pulse signal in gate open time determined in accordance with any one of said input and output signals of said measuring unit circuit and the output signal of said voltage controlled oscillator, the respective frequencies thereof being equal, a signal indicative of one of said capacitive part and said inductive part thereby being obtained.
Dependencies are inferred from the claim text.