基于磁转速信号的自适应增益采集系统设计

Design of Adaptive Gain Acquisition System Based on FPGA

摘要:

针对线圈式磁传感器随测量转速变化所产生的电动势信号幅值线性变化，为实现此类幅值与周期动态变化信号的无失真采集，设计了一种增益随输入信号幅值水平改变的自适应增益采集系统。本系统以现场可编程门阵列(FPGA)为控制核心，对输入信号幅值进行分析，根据幅值分析结果控制电路增益在-20dB~80dB范围内自适应改变，并记录系统当前时刻增益，根据当前增益还原得到输入信号，将增益信号和还原信号同步存储。采集信号经自适应增益后输出信号幅值控制在设定范围内，利于对动态信号中不同幅值区间信号变化细节直接观察。通过幅值在20μV~10V范围内转速信号输入测试，系统自适应增益后信号幅值控制在了0.1V~4V范围内，实现了对动态转速信号的无失真采集，验证了本自适应增益采集电路的性能，在高动态幅值信号采集领域，具有良好的应用前景。

Abstract:

The amplitude of the electromotive force signal generated by the coil magnetic sensor varies greatly with the change of measuring speed. In order to realize the distortion-free acquisition of such amplitude and periodic dynamic change signals, an adaptive gain acquisition system with the gain changing with the amplitude level of the input signal is designed. The system takes field programmable gate array (FPGA) as the control core, analyzes the amplitude of the input signal, and adaptively changes the gain of the control circuit in the range of -20dB~80dB according to the amplitude analysis result, records the current gain of the system, restores the input signal according to the current gain, and synchronously stores the gain signal and the restore signal. After adaptive gain, the amplitude of the output signal is controlled within the set range, which is conducive to the direct observation of the details of signal changes in different amplitude ranges of dynamic signals. Through the speed signal input test in the range of 20μV~10V, the signal amplitude of the system after adaptive gain is controlled in the range of 0.1V~4V, and the dynamic speed signal is acquired without distortion, and the performance of the adaptive gain acquisition circuit is verified. It has a good application prospect in the field of dynamic signal acquisition with high amplitude.