2022 NHCA Annual Virtual Conference

For impulsive noise, such as produced by weapons fire, it is often suggested that sampling rates of at least 200 kHz are necessary (e.g., MIL-STD-1474E) to accurately estimate the damage risk. In many cases, the driving motivation for this high sampling rate is to ensure a high level of temporal resolution in the impulse waveform. However, the Nyquist-Shannon sampling theorem specifies that a sampled signal can accurately reconstruct both the amplitude and phase information of a signal as long as the sampling rate is at least twice the highest frequency present in the original analog signal. Thus, it is possible to reconstruct a band-limited signal with the same temporal resolution as one captured at a higher sampling rate if the contributions of energy above the Nyquist rate can be ignored. Here we show how resampling techniques can be applied to a signal sampled at 48 kHz to extract A-weighted peak pressure estimates within 0.2 dB of those obtained at a higher sampling rate. The results suggest that sampling rates for impulsive noise should be based on the range of frequencies that are expected to make a meaningful contribution to the risk of injury, rather than on concerns about temporal resolution.