Method and apparatus for measuring electrical parameters using a differentiating current sensor and a digital integrator
US5485393A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 27, 1993 |
| Grant date | Jan 16, 1996 |
| Priority date | — |
| Expiry date | Jul 27, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R21/1331
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A digital current meter, usable either alone or in combination with a voltage meter, is disclosed. The current meter includes a current sensor which outputs the time derivative of the current flowing through the load being measured. The differentiated current signal is digitally sampled, usually by a sigma-delta sampler, filtered, and digitally integrated. A feedback path is provided to remove the direct-current (DC) component of the current signal, to keep the integrator from going out of range. A bleeder feedback channel around the digital integrator is provided to keep the digital integrator from permanently latching an impulse. In combination with a voltage meter, a half-sample delay is introduced in the current signal path, to compensate for the lead provided by the combination of the analog differentiator and the digital integrator, and the voltage signal path uses filters with the same characteristics as the current channel, to match the delay in the two channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.