METHODS AND APPARATUS FOR RECORDING IMPULSIVE SOUNDS

摘要

Loud sounds with fast rise times, like gunfire and explosions, can cause noise-induced hearing loss (NIHL). Unfortunately, current models do not adequately explain how impulsive sounds cause NIHL, which makes it difficult to predict and prevent NIHL on battlefields and other hostile or rugged environments. Fortunately, the impulsive sounds experienced by soldiers and others working in rugged environments can be recorded using a compact, portable system that acquires, digitizes, and stores high-bandwidth audio data. An example of this system can be mounted on a helmet or other article and used to record hours of audio data at a bandwidth of 20 kHz or higher, which is broad enough to capture sounds with rise times less than 50 ms. An analog-to-digital converter (ADC) digitizes these broadband audio signals at rate of 40 kB/s or higher to preserve the impulse information. A processor transfers the digitized samples from a buffer to a memory card for later retrieval using an interrupt-driven processing technique.

主权项

1. A portable system for recording sound in an environment subject to impulse noise characterized by an initial rise time, the portable system comprising:
a first microphone to produce a first analog signal representative of sound in a first amplitude range; a second microphone to produce a second analog signal representative of sound in a second amplitude range different than the first amplitude range; a combining/summing node, operably coupled to the first microphone and to the second microphone, to combine the first analog signal and the second analog signal into a combined analog signal having a combined amplitude range about equal to the sum of the first amplitude range and the second amplitude range; an analog-to-digital converter (ADC), operably coupled to the combining/summing node, to sample the combined analog signal at a sampling rate equal to or greater than twice the reciprocal of the initial rise time so as to produce a digital signal representative of the combined analog signal; and a processor, operably coupled to the ADC, to store a representation of the digital signal in a nonvolatile memory.