Phase sensitive demodulator is the key to the electrical capacitance fomography( ECT) system. The existence of low accuracy, great noise and long stability time of analog devices and other issues in traditional analog demodulation become a bottleneck in further improving accuracy and speed of ECT system. Based on the FPGA, it achieves a fast, high-precision signed digital phase sensitive demodulation. Validation shows that the digital phase sensitive demodulation complete enough to meet the requirements of ECT system in accuracy and speed.%相敏解调是电容层析成像(ECT)系统中的关键环节.传统的模拟解调存在着精度低、噪声大和模拟器件的稳定时间过长等问题,成为进一步提高ECT系统精度和速度的“瓶颈”.为此,设计了一种基于FPGA的数字相敏解调方法,实现了快速、高精度的有符号数字相敏解调.验证显示,设计的数字化相敏解调完全满足ECT系统对精度和速度的要求.
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