Digital-analog hybrid optical phase-lock loop for optical quadrature phase-shift keying

We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Considering the non-negligible loop delay, we optimize the loop natural frequency. Without error correction coding, a sensitivity of -37 dBm/-35 dBm is achieved, while the bit error rate is below 10-9 at 2.5 Gbaud/5 Gbaud rate.For the QPSK communication system, the bit rate is twice the baud rate. The loop natural frequency is 0.647 Mrad/s, and the minimized steady-state phase-error standard deviation is 3.83°.

基于高频正弦脉振电压注入的永磁电机无传感器控制策略

为了降低因固定频率高频信号注入而引起的额外噪声,减弱噪音污染,研究了一种基于随机信号注入的永磁电机无位置传感器控制方法。根据随机注入的特点,建立了随机高频正弦注入的电机数学模型。在此基础上,对随机正弦信号的产生及注入方式以及包络线信号的提取原理进行分析,设计了一个转子位置跟踪器,准确的获取永磁电机转子位置。最后,在永磁同步电机实验研究平台上进行了验证,通过对高频响应电流的功率谱密度进行分析,进一步证明了所研究方法对降低高频噪音的有效性。