Advanced digital telemetry system for monocable transmission featuring multilevel correlative coding and adaptive transversal filter equalizer
US5010333A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1989 |
| Grant date | Apr 23, 1991 |
| Priority date | — |
| Expiry date | May 17, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/12
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The present disclosure is directed to an improved telemetry system and data recovery telemetry receiver apparatus for installation with a logging cable supported sonde. In the sonde, a data stream is modulated onto a carrier after conversion by an encoder. Encoding involves conversion from a stream of binary data into four state symbols which are then encoded into seven duobinary levels. The availability of redundant levels permits correlation between encoded symbols and adjacent symbols. This is transmitted up the monocable to the surface and is recovered. The recovery involves amplification by an automatic gain control amplifier, conversion from an analog to digital form in an ADC, demodulation and reconstruction of the transmitted signal by means of a adaptive transversal filter equalizer featuring fractionally spaced sampling. Reconstructed output levels are then provided, and a slicer adjusts those values to the permitted seven levels. The data is then decoded. Extraordinary bandwidth compression is accomplished so that a large data flow can be provided through a monocable having only limited band pass capacity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.