Introduction to ultrasonic pseudo-random code systems

In the last decade many successful and advantageous sonic systems for imaging, flow measurement, and medium characterization have been published, which use pseudo-random coding to provide performance greatly superior to that of classic pulsed-echo techniques. However, no review of such pseudo-random code systems has been published, nor is the subject treated in any textbooks. Chapters 5 through 9 are intended to fill this gap by providing a tutorial introduction to the design of pseudo-random code systems and by reviewing the published work in this field as well as the work that either has not been published before or exists only in conference proceedings or theses. Since the review is dedicated to the use of pseudo-random code in ultrasound applications, it does not cover their use in spread spectrum communications or in spectroscopy. These two subjects are respectively covered by Dixon [1979] and Harwit and Sloan [1979].