Ess Technology, Inc.

Structural Monitoring Systems Ltd

Trevor Blake Lynch-Staunton

Dustin Forman

Henry Abe Kroker

Montana T C Reid

A sensing system () for monitoring the integrity of a structure has first and second channels (and) arranged for sealing onto a surface () of the structure () to form respective spaced apart first and second galleries (and). A fluid (F) is in the first gallery () and a fluid (F) is in the second gallery (). A measurement system () measures for a change in a pressure independent physical characteristic: a) in the first gallery (); b) in the second gallery (); c) between the first gallery () and the second gallery (); or d) a combination of two or more of a), b) and c) where the change is dependent on a mass flow of fluid from one of, or between, the sealed galleries due to a crack in the structure. The pressure independent physical characteristic of the fluid can be the conductivity of the fluid or the optical properties of the fluid.

Sensing system for monitoring the integrity of a structure

The present application describes an apparatus and method for reducing distortion in a class-D amplifier. The power output section of the amplifier is driven by an adjusted PWM signal, rather than by a PWM signal created directly from the input analog signal. A reference output, designed to closely track the input analog signal, is compared to the amplifier output. The resulting difference is an error signal which is inverted and summed with a second analog signal corresponding to the directly created PWM signal and changes the timing of the voltage transitions of the second analog signal. The changed voltage transitions are used to create the adjusted PWM signal. The inversion of the error signal causes negative feedback which results in the adjustment of the PWM signal being in a direction which reduces the error signal and thus the distortion of the amplifier.

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West Kelowna, Canada

Trevor Blake Lynch-Staunton