Design Of Analog Front-end For Neural Acquisition System

The interdisciplinary of neuroscience and electronics is one of the most advancedtopics. Scientists are tempting to use electronic technique to reconstruct the neural networkand implant the microelectrode into the brain, which make it possible to detect the electricactivities of single or groups of neurons. In this way we can better understand theoperational principle and mechanism of neurons and apply them into the development ofartificial neural nets etc. Studies about human brain and neural systems are one of the mostimportant areas in the high tech developing era. It is a milestone that the operationalprinciple of neural networks are discovered through electronic techniques and transmissionsof neural signals can be activated and even replaced by electronic signals, which provide abright way for the recovery of sensational and motional neurons.However, in order to realize the above goal, the basic premise is that we can attain theexact, effective and real-time electronic signals of neural cells, especially under thecircumstances of making sure of safety. The goal of this paper is to realize the acquisitionof electronic neural signals including the front amplification and analog to digitaltransformation under the application background of neural signal acquisition and recoverysystems invasive brain-computer interface, which provide the basics preparation of theconsequential digital processing.Even though the developing history of neural signal acquisition has been not short andthe technique has already been accumulated to some extent, few can be used into daily life.The equivalent input noise, DC bias and distortion etc. are still needed to devote lots ofenergy of researchers to finally realize a highly effective, real-time and exact neural signalacquisition.This paper illustrates the brain-computer interface of the invasive neural signalacquisition system and the signal acquisition processing module in details. Moreover, theinterface of neural circuits is discussed especially the characteristics of neural signals andmicroelectrodes and its electronic modules, which provide the theory supports of the frontend analog design.In addition, the main part of front end analog design is illustrated in the paper. The essence of analog low noise amplifier design in details is stated. The noise and powerconsumption of the amplifier are analyzed both from the constructive level and transmitterlevel. The trade-off optimal design is presented in the paper with the analysis of theories.The reason of chosen type of ADC is illustrated and theory analysis of the chosen ADC isstated. Behavioral modeling of ADC is proposed and the final design of circuits is givenbased on the results of behavioral modeling. The pre and post simulation results arepresented in the paper. Finally, the test results of4-channel Analog Front-ends for NeuralSignal Acquisition are shown and the analysis of results are given in this paper.