Broadband versus narrowband experimental methods in acoustics.

Abstract

Active acoustic measurements (those requiring the input of acoustic energy) can be broadly classified as either broadband or narrowband. In a broadband technique, the acoustic energy introduced into the system is highly localized in time (i.e., a sharp pulse). When transformed into the frequency domain using Fourier analysis, it becomes clear that this energy is spread over a wide frequency range. In a narrowband technique, the acoustic energy is introduced over a longer time period and occupies a much more localized region in the frequency domain. The limit being a single tone excitation signal. Benefits and drawbacks for each of these methods will be discussed as they are applied to several experimental systems including resonance and pulse-echo measurements.