Swept Frequency Acoustic Time Domain Reflection Measurement for Extraction of Acoustic Mode Velocities

The purpose of this paper is to discuss an extension of the swept frequency technique (SFT) for the extraction of acoustic velocities in piezoelectric materials, which uses data obtained by sweeping not only the acoustic waves launched at the fundamental transducer operating frequency, but also the waves generated by the harmonic operation of the transducer. The wideband S₁₁ response provides new detail in the extracted time-echo pulse, which allows a better "signature" in the extracted pulse shape, leading to better accuracy. In addition, further discussion of the concept of data padding for obtaining better time domain resolution of the extracted pulse delay is provided