ABSTRACT
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.
Subject(s)
Acoustics , Algorithms , Biophysical Phenomena , Computer-Aided Design , Equipment Design , Microwaves , Thermography , Methods , Tomography , MethodsABSTRACT
In order to improve the noise ratio and stability of the amplified small-signal in microwave-induced thermoacoustic tomography,an amplifying circuit with wide band and high voltage gain is designed in this paper.The results show that the voltage gain is up to 80dB and the bandwidth is about 7MHz.