Digitizing ohmmeter system
US6903558B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2003 |
| Grant date | Jun 7, 2005 |
| Priority date | — |
| Expiry date | Aug 9, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A digitizing ohmmeter system for providing a digital resistance measurement includes a current source for providing an excitation current to an impedance-varying input sensor and an ADC circuit including a charge-balancing modulator and a digital post processing circuit. The system utilizes synchronous AC excitation of the input sensor and an AC coupled analog-to-digital converter input. The digitizing ohmmeter system also implements correlated double sampling for noise cancellation to provide low noise and highly accurate analog-to-digital conversions. The ADC circuit includes a reference signal generator generating a resistance reference signal by time-sharing the excitation current with the input sensor. The digitizing ohmmeter system thereby realizes fully ratiometric operation such that neither a precise current source nor a precise voltage source is required for accurate resistance measurements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.