摘要
本文描述限幅式通讯隔声耳罩的设计及限幅隔声原理。试验表明:在125~800Hz平均隔声值为27.9dB;在500Hz中心频率,带宽为316Hz的粉红噪声,声级80dBA和75dBA环境下,戴耳罩接收75dB、70dB的单音字,清晰度分别为86.4%和84.4%,不戴则为70%和64.7%;经105dBA主机噪声暴露2h后,10名受试者听力测定,TTS_(2min)平均仅上升3dB,不戴该耳罩则上升26.1dB,其中4000Hz和6000Hz尤为严重,分别上升44dB和37.6dB,实验后第6天才能恢复,用中耳阻抗测定蹬骨肌反射阈变化,亦得到类似结论。温湿度试验表明,在50℃电热恒温水温箱(湿度>95%)和-20℃医用冰箱内各连续试验2h;电路增益仅变化2dB。
In this paper the design of limited amplitude communication earmuffand the limiting attenuation principle was described. The laboratory expe-riments and field studies showed that the average sound insulation levelwas 27.9dB at 125-8000 Hz. In the condition of noise level of 80 dBA and75 dBA (center frequency 500Hz, band 316Hz in pink noise) and speech le-vel of 75 dB and 70 dB, the intelligibility (single word) for listeners wea-ring earmuff were 86.7% and 84.6% respectively, however, for those notwearing earmuff were only 70% and 64.8%. When exposed to cabin noiseof 105dBA for two hours, TTSs2 was 3dB for subjects wearing earmuff but26.1dB for 10 subjects non-wearing earmuff, especially at 4000 Hz and6000Hz。The thresholds returned to normal 6 days after the expossure.The changes of circuit gain were only 2dB when the earmuff was exposedto temperature of 50 ℃ (relative humidity 95%) and to - 20℃
出处
《解放军预防医学杂志》
CAS
北大核心
1991年第6期408-412,共5页
Journal of Preventive Medicine of Chinese People's Liberation Army
关键词
耳罩
限幅
脉冲噪声
清晰度
limited amplitude
earmuff
impulse noise intelligibility