为了研究有源降噪系统仿真时电声器件的频率响应对次级通路建模的影响,使用有限脉冲响应(Finite Impulse Response, FIR)滤波器模拟电声器件的频率响应曲线,并以FxLMS(Filtered-x Least Mean Square)算法为例,研究扬声器与传声器的频率...为了研究有源降噪系统仿真时电声器件的频率响应对次级通路建模的影响,使用有限脉冲响应(Finite Impulse Response, FIR)滤波器模拟电声器件的频率响应曲线,并以FxLMS(Filtered-x Least Mean Square)算法为例,研究扬声器与传声器的频率响应对系统降噪效果的影响。仿真结果表明,在实际降噪应用中电声器件陡峭的频率响应曲线会对输入信号幅值造成衰减,产生幅值失配的现象,使控制系统的实际降噪量远小于理想电声器件模型,并通过不同情况下的降噪效果分析了电声器件对系统降噪量的影响。该分析方法为深入进行有源降噪系统研究提供了一种新的次级通道模型分析思路。展开更多
According to the World Health Organization (WHO), men and women older than 50 years present osteoporosis with reduced bone mass, this is one of the major impact morbidities causes in the world. It may be present in th...According to the World Health Organization (WHO), men and women older than 50 years present osteoporosis with reduced bone mass, this is one of the major impact morbidities causes in the world. It may be present in the hip, spine, and wrist. The gold standard technique for osteoporosis diagnosis is the Bone Densitometry (DXA). The evaluation of an electroacoustic device is as an alternative procedure for the validation and diagnosis of osteoporosis. Diagnosis of osteoporosis severity was carried out in 49 females by using the registers of the DEXA’s T-Score values. These were statistically compared with the measurements performed using the electroacoustic device. Non-Significative difference between measurements was found with ANOVA and Chi-square tests and the area for the ROC curve on electroacoustic devices was 0.551. The Bland Altman suggests an excellent concordance between both techniques. This is a non-invasive method that has a proper match with the gold standard. The study suggests that procedure measurements with the electroacoustic device could be implemented as an alternative clinical practice for osteoporosis diagnosis.展开更多
文摘为了研究有源降噪系统仿真时电声器件的频率响应对次级通路建模的影响,使用有限脉冲响应(Finite Impulse Response, FIR)滤波器模拟电声器件的频率响应曲线,并以FxLMS(Filtered-x Least Mean Square)算法为例,研究扬声器与传声器的频率响应对系统降噪效果的影响。仿真结果表明,在实际降噪应用中电声器件陡峭的频率响应曲线会对输入信号幅值造成衰减,产生幅值失配的现象,使控制系统的实际降噪量远小于理想电声器件模型,并通过不同情况下的降噪效果分析了电声器件对系统降噪量的影响。该分析方法为深入进行有源降噪系统研究提供了一种新的次级通道模型分析思路。
文摘According to the World Health Organization (WHO), men and women older than 50 years present osteoporosis with reduced bone mass, this is one of the major impact morbidities causes in the world. It may be present in the hip, spine, and wrist. The gold standard technique for osteoporosis diagnosis is the Bone Densitometry (DXA). The evaluation of an electroacoustic device is as an alternative procedure for the validation and diagnosis of osteoporosis. Diagnosis of osteoporosis severity was carried out in 49 females by using the registers of the DEXA’s T-Score values. These were statistically compared with the measurements performed using the electroacoustic device. Non-Significative difference between measurements was found with ANOVA and Chi-square tests and the area for the ROC curve on electroacoustic devices was 0.551. The Bland Altman suggests an excellent concordance between both techniques. This is a non-invasive method that has a proper match with the gold standard. The study suggests that procedure measurements with the electroacoustic device could be implemented as an alternative clinical practice for osteoporosis diagnosis.
