以某自动校时电子钟项目为例,在Cotex-M3内核芯片上采用面向对象编程方法分析项目的业务需求,提取业务逻辑的共性内容,并创建应用程序类。借鉴嵌入式操作系统时间片任务调度的方法,得到一种新的嵌入式项目编程解决方案,在无操作系统的...以某自动校时电子钟项目为例,在Cotex-M3内核芯片上采用面向对象编程方法分析项目的业务需求,提取业务逻辑的共性内容,并创建应用程序类。借鉴嵌入式操作系统时间片任务调度的方法,得到一种新的嵌入式项目编程解决方案,在无操作系统的微控制单元(Micro Control Unit,MCU)上实现时间片调度应用程序对象,用以提升程序的条理性,增强代码的可移植性和复用性,便于程序的扩展。展开更多
This paper considers blind chip rate estimation of DS-SS signals in multi-rate and multi-user DS-CDMA systems over channels having slow flat Rayleigh fading plus additive white Gaussian noise. Channel impulse response...This paper considers blind chip rate estimation of DS-SS signals in multi-rate and multi-user DS-CDMA systems over channels having slow flat Rayleigh fading plus additive white Gaussian noise. Channel impulse response is estimated by a subspace method, and then the chip rate of each signal is estimated using zero crossing of estimated differential channel impulse response. For chip rate estimation of each user, an algorithm which uses weighted zero-crossing ratio is proposed. Maximum value of the weighted zero crossing ratio takes place in the Nyquist rate sampling frequency, which equals to the twice of the chip rate. Furthermore, bit time of each user is estimated using fluctuations of autocorrelation estimators. Since code length of each user can be obtained using bit time and chip time ratio. Fading channels reduce reliability factor of the proposed algo-rithm. To overcome this problem, a receiver with multiple antennas is proposed, and the reliability factor of the proposed algorithm is analyzed over both spatially correlated and independent fading channels.展开更多
文摘以某自动校时电子钟项目为例,在Cotex-M3内核芯片上采用面向对象编程方法分析项目的业务需求,提取业务逻辑的共性内容,并创建应用程序类。借鉴嵌入式操作系统时间片任务调度的方法,得到一种新的嵌入式项目编程解决方案,在无操作系统的微控制单元(Micro Control Unit,MCU)上实现时间片调度应用程序对象,用以提升程序的条理性,增强代码的可移植性和复用性,便于程序的扩展。
文摘This paper considers blind chip rate estimation of DS-SS signals in multi-rate and multi-user DS-CDMA systems over channels having slow flat Rayleigh fading plus additive white Gaussian noise. Channel impulse response is estimated by a subspace method, and then the chip rate of each signal is estimated using zero crossing of estimated differential channel impulse response. For chip rate estimation of each user, an algorithm which uses weighted zero-crossing ratio is proposed. Maximum value of the weighted zero crossing ratio takes place in the Nyquist rate sampling frequency, which equals to the twice of the chip rate. Furthermore, bit time of each user is estimated using fluctuations of autocorrelation estimators. Since code length of each user can be obtained using bit time and chip time ratio. Fading channels reduce reliability factor of the proposed algo-rithm. To overcome this problem, a receiver with multiple antennas is proposed, and the reliability factor of the proposed algorithm is analyzed over both spatially correlated and independent fading channels.
