APPARATUS AND METHOD UTILIZING MULTI-BIT SYMBOL STREAM IN DIRECTIONAL DRILLING SYSTEM

摘要

A system includes a transmitter for use in conjunction with a horizontal directional drilling system that transmits a multi-bit symbol stream that characterizes sensor symbols for receipt by an aboveground portable device. The portable device receives the symbol stream for aboveground recovery of the sensor signals. The transmitter can precisely place the symbol frequencies at least to avoid a noise environment, as well as to avoid powerline harmonics, and can utilize wave shaping for transmitted symbols at least to provide for transmission power control, spectral content control and wideband antenna matching. The receiver can measure the noise environment to identify the symbol frequencies used by the transmitter. The noise can be scanned at an incremental resolution across a wide frequency bandwidth for display or automatic symbol frequency selection.