头盔的声学性能测试与分析

本文设计了使用自相关函数以测试混响声衰变速度、自功率谱以测试插入损失的方法，用于头盔的回声与隔声效果分析．结果表明，这一方法物理概念明确，测试简单，可以定量地说明头盔的声学性能可能存在的问题，可望用于头盔的声学性能客观测试与分析方法的建立．

Measurement and analysis of the acoustical characteristics of helmets

To analyze the echo effect and sound insulation property of a helmet, aoto-correlations, auto-power spectra of the incident sound signal at the ears are measured.The auto-correlations can give the rate of echo sound decay and the auto-power spectrumdifferences can describe the insertion loss. The physical concept of the method is clearand the measurement is simple. The results can quantitatively explain where the possi-ble problem in the acoustical characteristics of analysed helmets lies. It is prospective toestablish a standard on the objective measurement and analysis of acoustical character-istics of helmets.