Wei Yusen, Wang Hua, Zhu Xinya, Jiao Teng, Yang Guosheng
Department of Biomedical Engineering, The Fourth Military Medical University, Xi'an 710032, China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2009 Jun;26(3):471-4.
According to the results of analyzing the microwave-induced thermoacoustic signals, the amplitude and frequency were estimated and the designing parameters of preprocessor were decided. Based on the parameters, the signals preprocessor was designed with the band pass frequency ranging from 50 KHz to 3MHz, the gain ranging from 55 dB to 105 dB and the output noise being 1.32 V when the input was zero and the gain was 105 dB. The de-noising method of thermoacoustic signals was also discussed. The signals can be picked up by the preprocessor combined with the digital multipoint average method. The amplitude of signals is only 5 microV or even less. The results indicated that the preprocessor can meet the needs of thermoacoustic signals acquisition in bandwidth, gain and noise control.
根据对微波诱导热声信号的分析结果，估算了信号的幅度和频率，并确定了预处理装置的设计参数。基于这些参数，设计了信号预处理装置，其带通频率范围为50kHz至3MHz，增益范围为55dB至105dB，当输入为零且增益为105dB时输出噪声为1.32V。还讨论了热声信号的去噪方法。通过预处理装置结合数字多点平均法可以采集到信号。信号幅度仅为5微伏甚至更小。结果表明，该预处理装置在带宽、增益和噪声控制方面能够满足热声信号采集的需求。
