Downhole digital power amplifier for a measurements-while-drilling telemetry system
US4468665A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 30, 1981 |
| Grant date | Aug 28, 1984 |
| Priority date | — |
| Expiry date | Jan 30, 2001 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/13
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A downhole digital power amplifier comprises a device which, through digital means, provides a sinusoidal, variable frequency, variable power and variably phase-shift modulated output for the transmission of data from a downhole sensor arrangement to an uphole receiver. Selection and variation of frequency, power and modulation are made through digital inputs. The device provides these functions at extra low frequencies (ELF) low-to-high power output, and varying phase-shift keying. The downhole digital power amplifier (68) comprises, in a preferred embodiment, an input shift register (81) for receiving a digital bit stream, a programmable frequency divider (82), a dead man timer circuit (84), a counter (86), a sync circuit (88), a PROM (90) (programmable read-only memory) for generating a digital sinusoidal output, a DAC (92) (digital-to-analog converter) for converting the digital sinusoidal output to an analog sinusoidal output, a power supply control circuit (94), an analog divider (96), and a conventional power amplifier (98). The dead man timer circuit detects normal operation and a fault condition, and controls the power supply control circuit to "power down" the amplifier w…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.