Researching on the Preprocessor of Microwave-Induced Thermoacoustic Signals

According to analyzing the microwave-induced thermoacoustic signals, the ranges of the amplitude and frequency were estimated and the designing parameters of preprocessor were decided. Based on the parameters, the signal preprocessor was designed with band pass frequency range from 100 KHz to 2.5 MHz, gain range from 55 dB to 100 dB and output noise is 845 mV when the input was zero and the gain was 100 dB. The signals, which were amplified 88 dB by the preprocessor, were obtained from the experiment successfully. The de-noising method of these signals was also discussed. The results indicated that the preprocessor can meet the needs of thermoacoustic signals acquisition in bandwidth, gain and noise control very well.