Signal recovery using a cascade adaptive filter: application to ultrasonic testing of heterogeneous media
Patrick A. Gaydecki · Measurement Science and Technology · 1997
The basic principles of an adaptive filter implemented in discrete space are discussed, and an algorithm for a two-stage cascade adaptive filter using the least-mean-squares method is given. The filter was employed to process digitised low-frequency ultrasonic signals propagated through concrete, obtained under a variety of transducer/sample coupling conditions. Very significant levels of signal recovery were possible with waveforms initially exhibiting poor signal-to-noise ratios arising from high levels of amplifier gain.