A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for meastwing lowfrequency weak signal...A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for meastwing lowfrequency weak signal. Digital signal sequence is obtained through sampling signal measured over an integer number of signal periods, but digital reference sequence is acquired through mathematical operation, then digital phase sensitive detection can be implemented by calculating the cross-correlation function of digital signal sequence and digital reference sequence. In addition, the frequency response and phase character of the digital lock-in amplifier is analyzed. Finally, the designed digital lock-in amplifier is achieved. Expermental results show that the digital lock-in amplifier can be used for measuring weak signal with low ignal-to-noise ratio.展开更多
In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock...In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference.The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle.The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface.In the implementation of digital lock-in amplifier,a new routine which warranted the exactly matching of the reference phase to signal phase was proposed.The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal.The non linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degrees.The application of the software demodulation in the signal detection of micro-electro-mechanical-system(MEMS)device is a new attempt,and it shows the prospective for a high-performance application.展开更多
在光电检测系统的设计中,往往采用锁相检测系统来消除1/f噪声和其他外部的噪音。论文是在Alter公司DSP Builder基础上设计的数字锁相放大器,同时为避免待测信号与参考信号的失配,增设了频率自动跟踪模块,从而更好地实现参考信号频率的匹...在光电检测系统的设计中,往往采用锁相检测系统来消除1/f噪声和其他外部的噪音。论文是在Alter公司DSP Builder基础上设计的数字锁相放大器,同时为避免待测信号与参考信号的失配,增设了频率自动跟踪模块,从而更好地实现参考信号频率的匹配,确保测量精度。经过仿真验证可行后,将编译好的程序下载到FPGA器件中,并对硬件电路进行设计和测试。实验结果表明,在待测信号的信噪比RSNR≈-10 d B时,最小检测幅值为50μV,锁频相对误差小于0.015%,待测信号幅值的测量相对误差小于0.11%。因此该自动频率跟踪数字锁相放大器可以有效实现微弱光电信号的检测。展开更多
文摘A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for meastwing lowfrequency weak signal. Digital signal sequence is obtained through sampling signal measured over an integer number of signal periods, but digital reference sequence is acquired through mathematical operation, then digital phase sensitive detection can be implemented by calculating the cross-correlation function of digital signal sequence and digital reference sequence. In addition, the frequency response and phase character of the digital lock-in amplifier is analyzed. Finally, the designed digital lock-in amplifier is achieved. Expermental results show that the digital lock-in amplifier can be used for measuring weak signal with low ignal-to-noise ratio.
基金The National Natural Science Foundation ofChina(No.60402003)The National High Technology Research and Development Pro-gram of China(863Program)(No.2002AA745120)
文摘In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference.The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle.The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface.In the implementation of digital lock-in amplifier,a new routine which warranted the exactly matching of the reference phase to signal phase was proposed.The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal.The non linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degrees.The application of the software demodulation in the signal detection of micro-electro-mechanical-system(MEMS)device is a new attempt,and it shows the prospective for a high-performance application.
文摘在光电检测系统的设计中,往往采用锁相检测系统来消除1/f噪声和其他外部的噪音。论文是在Alter公司DSP Builder基础上设计的数字锁相放大器,同时为避免待测信号与参考信号的失配,增设了频率自动跟踪模块,从而更好地实现参考信号频率的匹配,确保测量精度。经过仿真验证可行后,将编译好的程序下载到FPGA器件中,并对硬件电路进行设计和测试。实验结果表明,在待测信号的信噪比RSNR≈-10 d B时,最小检测幅值为50μV,锁频相对误差小于0.015%,待测信号幅值的测量相对误差小于0.11%。因此该自动频率跟踪数字锁相放大器可以有效实现微弱光电信号的检测。
