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Aim 3

The third aim was to develop acoustic pulse reflectometry to enable the measurement of longer instruments and to speed up the measurement process.

In the original pulse reflectometry method, a cylindrical connector called the ``dc tube'' was placed between the source tube and the object under test. This was necessary to enable easy removal of the dc offset in the measurement upon which the bore reconstruction is highly sensitive. By developing the virtual dc tube method, the need for attaching this cylindrical connector was eliminated, making the measurement process quicker, more reliable and compact. In addition to this, a source reflection cancellation method was shown to successfully remove the reflections from the source, enabling the measurement of longer objects. MLS excitation has been shown to be useful for improving signal to noise ratio, thereby removing the need to perform many measurements and average the results.

Jonathan Kemp 2003-03-24