# US 2025/0093286 A1 · Impedance measuring device and method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2025/0093286 A1
- Document ID: US20250093286A1
- Status: Published application
- Kind: A1
- Application number: 18/729,682
- Filed: 2022-10-26
- Published: 2025-03-20
- Earliest claimed: 2022-01-21
- Assignees: Hioki E.E. Corporation
- Applicants: Hioki E.E. Corporation
- Inventors: Kazuaki HANEDA; Tomohiro YOKOYAMA
- Web page: https://patentgrep.com/patent/US20250093286A1

## CPC

- G01N 27/02: by investigating impedance
- G01R 27/14: Measuring resistance by measuring current or voltage obtained from a reference source (G01R27/16, G01R27/20, G01R27/22 take precedence)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

An impedance measuring device capable of reducing influence of noise near a measurement frequency, and performing highly accurate measurement is provided. The problem can be solved by an impedance measuring device or the like, including: a signal generation unit that generates a first reference signal, and a second reference signal that is obtained by inverting a phase of the first reference signal at an interval of a predetermined inversion period; a measurement signal supply unit that produces a measurement signal based on the second reference signal, and supplies the measurement signal to a measurement object; a measuring unit that synchronously detects a signal occurring in the measurement object due to the measurement signal, using a modulation signal produced based on the first reference signal, and further produces a filtered signal by low-pass filtering the detected signal; and an arithmetic unit that determines impedance of the measurement object, based on an added average of a magnitude of the filtered signal when the first reference signal and the second reference signal are in phase, and a magnitude of the filtered signal with inverted sign when the first reference signal and the second reference signal are in anti-phase.

## Claims

### Claim 1

An impedance measuring device comprising:
a signal generation unit that generates a first reference signal, and a second reference signal that is obtained by inverting a phase of the first reference signal at an interval of a predetermined inversion period;
a measurement signal supply unit that produces a measurement signal, based on the second reference signal, and supplies the measurement signal to a measurement object;
a measuring unit that synchronously detects a signal occurring in the measurement object due to the measurement signal, using a modulation signal produced based on the first reference signal, and further produces a filtered signal by low-pass filtering the detected signal; and
an arithmetic unit that determines impedance of the measurement object, based on an added average of a magnitude of the filtered signal when the first reference signal and the second reference signal are in phase, and a magnitude of the filtered signal with inverted sign when the first reference signal and the second reference signal are in anti-phase.

### Claim 2

An impedance measuring device comprising:
a signal generation unit that generates a first reference signal, and a second reference signal that is obtained by inverting a phase of the first reference signal at an interval of a predetermined inversion period;
a measurement signal supply unit that produces a measurement signal, based on the second reference signal, and supplies the measurement signal to a measurement object;
a measuring unit that synchronously detects a signal occurring in the measurement object due to the measurement signal, using a modulation signal produced based on the second reference signal, and further produces a filtered signal by low-pass filtering the detected signal; and
an arithmetic unit that determines impedance of the measurement object, based on an added average of a magnitude of the filtered signal when the first reference signal and the second reference signal are in phase, and a magnitude of the filtered signal when the first reference signal and the second reference signal are in anti-phase.

### Claim 3 (depends on 1)

The impedance measuring device according to claim 1, wherein
the inversion period is an integral multiple of a period of the measurement signal, and
the arithmetic unit determines the impedance of the measurement object, based on an added average over a measurement time period that is an integral multiple of the inversion period.

### Claim 4

A method comprising steps of:
generating a first reference signal, and a second reference signal that is obtained by inverting a phase of the first reference signal at an interval of a predetermined inversion period;
producing a measurement signal, based on the second reference signal, and supplying the measurement signal to a measurement object;
synchronously detecting a signal occurring in the measurement object due to the measurement signal, using a modulation signal produced based on the first reference signal, and further producing a filtered signal by low-pass filtering the detected signal; and
determining impedance of the measurement object, based on an added average of a magnitude of the filtered signal when the first reference signal and the second reference signal are in phase, and a magnitude of the filtered signal with inverted sign when the first reference signal and the second reference signal are in anti-phase.

### Claim 5

A method comprising steps of:
generating a first reference signal, and a second reference signal that is obtained by inverting a phase of the first reference signal at an interval of a predetermined inversion period;
producing a measurement signal based on the second reference signal, and supplying the measurement signal to a measurement object;
synchronously detecting a signal occurring in the measurement object due to the measurement signal, using a modulation signal produced based on the second reference signal, and further producing a filtered signal by low-pass filtering the detected signal; and
determining impedance of the measurement object, based on an added average of a magnitude of the filtered signal when the first reference signal and the second reference signal are in phase, and a magnitude of the filtered signal when the first reference signal and the second reference signal are in anti-phase.

### Claim 6 (depends on 2)

The impedance measuring device according to claim 2, wherein
the inversion period is an integral multiple of a period of the measurement signal, and
the arithmetic unit determines the impedance of the measurement object, based on an added average over a measurement time period that is an integral multiple of the inversion period.