Teledrill, Inc.

S Tom Thawley

John J Goiffon

Craig M Scott

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 when reception of a digital bit stream is not imminent during normal operation, and controls the power supply control circuit to periodically generate a 'failure informant' message during a fault condition.

Downhole digital power amplifier for a measurements-while-drilling

A heat sink/retainer clip (54) capable of resiliently holding objects, such as printed circuit boards, in tubular members, such as telemetering tools. The heat sink/retainer clip comprises two portions (56, 60) which extend across the tube from opposite sides thereof and two portions (58, 62) which engage the inner periphery of a tube (48). The clip is made of a resilient material, and the outer radii of the second two portions is slightly greater than the inner radius of the tube, so that the clip is distorted by the tube, during assembly, to resiliently grip the object between the first two portions.

Growing community of inventors

Dallas, TX, United States of America

S Tom Thawley