Cancellation of tool mode signal from combined signal
US5780784A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1996 |
| Grant date | Jul 14, 1998 |
| Priority date | — |
| Expiry date | Oct 17, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V1/46
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for eliminating the tool mode signal from a received combined signal comprising both tool mode and formation mode components, comprising: a formation receiver for receiving said combined signal, a reference receiver for receiving a tool mode reference signal, a filter for processing said tool mode reference signal and generating a predicted tool mode component of the combined signal, and a summation element for subtracting said predicted tool mode component from said combined signal and generating a predicted formation mode component. The filter preferably incorporates a portion of the output of the summation element as an error signal, enabling the filter to adapt to changing conditions and update the algorithm on which it makes its predictions. According to an alternative system, an average value for the tool mode signal is updated according to a moving average to which new data points are added as they become available. Tool mode signals are distinguishable from signals having both components because they have lower energies. When a signal is received having the lower energy that is indicative of the absence of a formation mode signal, the data point is treated as a pur…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.