In the storage ring RF system of Shanghai Synchrotron Radiation Facility,the clock distribution and the local oscillator are two parts of the digital low level radio frequency hardware board.In this paper,we designed ...In the storage ring RF system of Shanghai Synchrotron Radiation Facility,the clock distribution and the local oscillator are two parts of the digital low level radio frequency hardware board.In this paper,we designed and produced the clock distribution and the local oscillator board using the AD9858 and AD9510 chips.The results show that the phase noise of the local oscillator signal is lower than 100dBc/Hz with 50 kHz offset.展开更多
微处理器芯片的生态建设是高端装备与智能微系统自主、可控的关键,尽管国产数字信号处理(digital signal processing, DSP)器件及其相关开发应用技术近年来得到了一定的发展,但与需求仍存在较大差距。在主动噪声控制领域,前馈型多通道...微处理器芯片的生态建设是高端装备与智能微系统自主、可控的关键,尽管国产数字信号处理(digital signal processing, DSP)器件及其相关开发应用技术近年来得到了一定的发展,但与需求仍存在较大差距。在主动噪声控制领域,前馈型多通道控制方案比单通道有较大的控制范围和较好的性能,但对系统的运算能力有较高的要求。文章以多通道FxLMS算法为基础,对多通道降噪系统的运算量进行了分析,依据国产DSP开发板的电路结构,设计了控制系统方案,并进行了实验研究。实验表明,所设计的噪声控制系统运算效率较ARM作为运算器提高了80%,对100~1 000 Hz内的周期性噪声信号衰减达到15~20 dB,证明了该方案的正确性。展开更多
The IEEE Standard 1149.1 boundary scan (BS) implementation provides the internal access required for testing the digital printed circuit board (PCB). However, the integrity of the boundary scan test infrastructure sh...The IEEE Standard 1149.1 boundary scan (BS) implementation provides the internal access required for testing the digital printed circuit board (PCB). However, the integrity of the boundary scan test infrastructure should be tested first to guarantee the validation of the results of the rest functional test and diagnosis. This paper describes the fault models and test principles of the BS test access port (TAP) lines on PCBs. A test algorithm with high fault coverage and short time is then presented for the PCB on which all ICs are BS ones.展开更多
基金Supported by Shanghai Synchrotron Radiation Facility
文摘In the storage ring RF system of Shanghai Synchrotron Radiation Facility,the clock distribution and the local oscillator are two parts of the digital low level radio frequency hardware board.In this paper,we designed and produced the clock distribution and the local oscillator board using the AD9858 and AD9510 chips.The results show that the phase noise of the local oscillator signal is lower than 100dBc/Hz with 50 kHz offset.
文摘The IEEE Standard 1149.1 boundary scan (BS) implementation provides the internal access required for testing the digital printed circuit board (PCB). However, the integrity of the boundary scan test infrastructure should be tested first to guarantee the validation of the results of the rest functional test and diagnosis. This paper describes the fault models and test principles of the BS test access port (TAP) lines on PCBs. A test algorithm with high fault coverage and short time is then presented for the PCB on which all ICs are BS ones.
