US 5,345,182 A · Impedance meter capable of performing measurements at high precision over wide impedance and frequency ranges

Abstract

A system for measuring a broad range of impedance values with high precision and over a broad frequency band. Both the broadrange impedance measurement capability of the V-I method and the broadband frequency measuring capability of the reflection coefficient method are provided. A remote measurement capability is also available. Based upon the V-I method, a selection is made between a circuit to achieve an ideal open and a circuit to achieve an ideal short circuit in response to the impedance values. A boundary for selecting the impedance is, for instance, 50.OMEGA.. To measure a high impedance, the ideal open type circuit is selected; to measure a low impedance, the ideal short circuit is selected. The source and measuring instruments are extended by a coaxial cable. A floating measuring instrument is obtained by using a balun. Impedance measurements for 1 MHz to 2 GHz are possible.

Claims19

Dependent claims

An impedance meter, comprising:

(a) a signal source comprising means for exciting a device under test (DUT);
(b) a first measuring instrument for measuring a first voltage indicative of a voltage drop across said DUT;
(c) a second measuring instrument for measuring a second voltage indicative of a current through said DUT;
and
(d) switching means for switching the interconnection of said signal source and said first and second measuring instruments between an ideal open type circuit and an ideal short circuit type circuit in response to a DUT impedance determined on the basis on said first and second voltages, said ideal open and ideal short circuit type circuits being pre-defined circuit configurations;
wherein the DUT impedance is a function of at least said first and second voltages.

3 more elements

A method for measuring an impedance of a device under test (DUT), wherein the DUT is operatively interconnected with first and second voltage measuring instruments and a signal source, comprising the steps of:

(a) exciting a DUT with a signal source;
(b) measuring, with a first measuring instrument, a first voltage indicative of a voltage drop across said DUT;
(c) measuring, with a second measuring instrument, a second voltage indicative of a current through said DUT;
(d) determining a DUT impedance on the basis of said first and second voltages;
and
(e) switching the interconnection of said signal source and said first and second measuring instruments between an ideal open type circuit and an ideal short circuit type circuit in response to the DUT impedance determined on the basis on said first and second voltages, said ideal open and ideal short circuit type circuits being predefined circuit configurations;
wherein the DUT impedance is a function of at least said first and second voltages.

4 more elements

Dependencies are inferred from the claim text.

Impedance meter capable of performing measurements at high precision over wide impedance and frequency ranges

Life of this patent

Impedance meter capable of performing measurements at high precision over wide impedance and frequency ranges

Life of this patent

Abstract

Claims19