Adaptive removal of resonance-induced noise
US5960091A · kind A · utility
Inventors
Key dates
| Filing date | Apr 25, 1997 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | Apr 25, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2017/0297
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Noise is removed from the digitized output of a sensor, subject to undesired resonance, even when the resonant frequency is unknown or drifts, with sufficiently low phase delay for the sensor to be used in closed-loop control. A very narrow notch filter which removes the resonance-induced noise is recursive (IIR) and therefore has a low phase delay. However, the apparatus which determines the center frequency of the notch filter is non-recursive, and therefore stable. It includes a tunable FIR filter which tracks the same resonance that we wish the IIR filter to remove. Tuning the FIR filter to minimize the output of the FIR filter therefore tunes the notch frequency to align with the resonant frequency. The tuning parameter which adaptively produces this result is suitably scaled and biased, and is applied to the IIR filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.