In order to predict bifurcation point of the closed-loop current-programmed boost converter and enable this converter to operate at stable parameter space, this paper firstly establishes stroboscopic maps for this con...In order to predict bifurcation point of the closed-loop current-programmed boost converter and enable this converter to operate at stable parameter space, this paper firstly establishes stroboscopic maps for this converter in the continuous conduction mode according to operating characteristics and topple of this converter. Parameter space at the steady state and bifurcation types are analysed together with stability theory of nonlinear equation. In the solving course, the duty cycle is avoided because of inversive solution, and accuracy is increased. Finally, correction is proved by numerical calculation.展开更多
在复杂的语音环境中,利用麦克风阵列语音增强技术能有效地拾取目标语音信号并消除噪声干扰,但传统的麦克风阵列波束形成的加权系数是固定的.为了能灵活地控制麦克风阵列波束的形成方向以及消除其波束旁瓣带来的残余噪声,提出了一种基于...在复杂的语音环境中,利用麦克风阵列语音增强技术能有效地拾取目标语音信号并消除噪声干扰,但传统的麦克风阵列波束形成的加权系数是固定的.为了能灵活地控制麦克风阵列波束的形成方向以及消除其波束旁瓣带来的残余噪声,提出了一种基于麦克风阵列的自适应语音增强技术.该技术将自适应滤波器和麦克风阵列相结合形成波束可控的广义旁瓣消除器,然后在广义旁瓣消除器后面续接一个改进的谱减法,并加入契比雪夫窗函数.仿真实验结果表明,所提出的语音增强方法能有效去除语音信号中的噪声干扰,相比于传统广义旁瓣消除器,信噪比大约提高了3.5 d B.展开更多
针对噪声背景下弱信号检测问题,设计了一种基于锁定放大原理的微弱信号检测系统。该系统基于CD4052模拟开关芯片、LM339比较器与CPLD可编程芯片,包括五个组成部分:微弱信号发生电路、信号调理电路、测频与移相电路、锁定放大电路与模拟...针对噪声背景下弱信号检测问题,设计了一种基于锁定放大原理的微弱信号检测系统。该系统基于CD4052模拟开关芯片、LM339比较器与CPLD可编程芯片,包括五个组成部分:微弱信号发生电路、信号调理电路、测频与移相电路、锁定放大电路与模拟-数字转换器。对每部分硬件电路作了详细分析和设计。实验结果显示所设计的弱信号检测系统能检测信噪比为20 d B,幅度10μV微弱信号。展开更多
文摘In order to predict bifurcation point of the closed-loop current-programmed boost converter and enable this converter to operate at stable parameter space, this paper firstly establishes stroboscopic maps for this converter in the continuous conduction mode according to operating characteristics and topple of this converter. Parameter space at the steady state and bifurcation types are analysed together with stability theory of nonlinear equation. In the solving course, the duty cycle is avoided because of inversive solution, and accuracy is increased. Finally, correction is proved by numerical calculation.
文摘在复杂的语音环境中,利用麦克风阵列语音增强技术能有效地拾取目标语音信号并消除噪声干扰,但传统的麦克风阵列波束形成的加权系数是固定的.为了能灵活地控制麦克风阵列波束的形成方向以及消除其波束旁瓣带来的残余噪声,提出了一种基于麦克风阵列的自适应语音增强技术.该技术将自适应滤波器和麦克风阵列相结合形成波束可控的广义旁瓣消除器,然后在广义旁瓣消除器后面续接一个改进的谱减法,并加入契比雪夫窗函数.仿真实验结果表明,所提出的语音增强方法能有效去除语音信号中的噪声干扰,相比于传统广义旁瓣消除器,信噪比大约提高了3.5 d B.
文摘针对噪声背景下弱信号检测问题,设计了一种基于锁定放大原理的微弱信号检测系统。该系统基于CD4052模拟开关芯片、LM339比较器与CPLD可编程芯片,包括五个组成部分:微弱信号发生电路、信号调理电路、测频与移相电路、锁定放大电路与模拟-数字转换器。对每部分硬件电路作了详细分析和设计。实验结果显示所设计的弱信号检测系统能检测信噪比为20 d B,幅度10μV微弱信号。
