针对海洋环境中不同温度下声音检测的需求,研发了一种基于光纤布喇格光栅(FBG)的温度补偿型水听器。该水听器利用侧面拉伸式结构进行增敏,通过有限元分析方法对水听器结构进行优化,并在该结构中使用了补偿材料聚甲基丙烯酸甲酯(PMMA),...针对海洋环境中不同温度下声音检测的需求,研发了一种基于光纤布喇格光栅(FBG)的温度补偿型水听器。该水听器利用侧面拉伸式结构进行增敏,通过有限元分析方法对水听器结构进行优化,并在该结构中使用了补偿材料聚甲基丙烯酸甲酯(PMMA),利用其热膨胀效应对FBG进行调制,以降低温度对FBG产生的影响,实现温度补偿。仿真结果表明:该结构在10~2000 Hz范围内可实现较高增敏,同时水听器的灵敏度增益谱显示出共振特征,相比于远离共振频率处,灵敏度增益有进一步的提高,最高达到145 d B;在海洋温度变化范围内(-2℃~30℃)可实现波长偏移小于0.01006 nm的温度补偿。展开更多
The capacity of mobile communication system is improved by using Voice Activity Detection (VAD) technology. In this letter, a novel VAD algorithm, SVAD algorithm based on Fuzzy Neural Network Knowledge Discovery (FNNK...The capacity of mobile communication system is improved by using Voice Activity Detection (VAD) technology. In this letter, a novel VAD algorithm, SVAD algorithm based on Fuzzy Neural Network Knowledge Discovery (FNNKD) method is proposed. The performance of SVAD algorithm is discussed and compared with traditional algorithm recommended by ITU G.729B in different situations. The simulation results show that the SVAD algorithm performs better.展开更多
The present study explores the forward mask-ing of the two-tone stimuli in sequence that evoked responses in the inferior colliculus (IC) of the echolocating bats. The results indicate that forward masking is obvious ...The present study explores the forward mask-ing of the two-tone stimuli in sequence that evoked responses in the inferior colliculus (IC) of the echolocating bats. The results indicate that forward masking is obvious in the acoustic responses of the IC neurons to the two-tone stimuli. Meanwhile the intensity sensitivity of the neurons respond-ing to the probe increases with the inter-tone interval de-creasing. The effects of forward masking are correlated with the relative intensity and the interval between the masker and probe. That is, the effects of forward masking are re-duced with the masker intensity decreasing and enhanced with the probe intensity decreasing and the inter-tone inter-val shortened. The present study suggests that there is a cor-relation between the characteristics of the response to the probe and the dynamic conditions of the postsynaptic cur-rents in the IC neurons.展开更多
文摘针对海洋环境中不同温度下声音检测的需求,研发了一种基于光纤布喇格光栅(FBG)的温度补偿型水听器。该水听器利用侧面拉伸式结构进行增敏,通过有限元分析方法对水听器结构进行优化,并在该结构中使用了补偿材料聚甲基丙烯酸甲酯(PMMA),利用其热膨胀效应对FBG进行调制,以降低温度对FBG产生的影响,实现温度补偿。仿真结果表明:该结构在10~2000 Hz范围内可实现较高增敏,同时水听器的灵敏度增益谱显示出共振特征,相比于远离共振频率处,灵敏度增益有进一步的提高,最高达到145 d B;在海洋温度变化范围内(-2℃~30℃)可实现波长偏移小于0.01006 nm的温度补偿。
文摘The capacity of mobile communication system is improved by using Voice Activity Detection (VAD) technology. In this letter, a novel VAD algorithm, SVAD algorithm based on Fuzzy Neural Network Knowledge Discovery (FNNKD) method is proposed. The performance of SVAD algorithm is discussed and compared with traditional algorithm recommended by ITU G.729B in different situations. The simulation results show that the SVAD algorithm performs better.
基金supported by the National Natural Science Foundation of China(Grant No.30170313)the Ph.D.Education Fund of China(Grant No.2000026905)and the NSF of USA.`
文摘The present study explores the forward mask-ing of the two-tone stimuli in sequence that evoked responses in the inferior colliculus (IC) of the echolocating bats. The results indicate that forward masking is obvious in the acoustic responses of the IC neurons to the two-tone stimuli. Meanwhile the intensity sensitivity of the neurons respond-ing to the probe increases with the inter-tone interval de-creasing. The effects of forward masking are correlated with the relative intensity and the interval between the masker and probe. That is, the effects of forward masking are re-duced with the masker intensity decreasing and enhanced with the probe intensity decreasing and the inter-tone inter-val shortened. The present study suggests that there is a cor-relation between the characteristics of the response to the probe and the dynamic conditions of the postsynaptic cur-rents in the IC neurons.
