Fatemeh Karami Horestani ¹, Mohammad Eshghi ¹, Mohammadreza Yazdchi ²

Affiliations
1 Electrical & Computer Engineering faculty, Shahid BeheshtiUniversity, Tehran, IR
2 Biomedical Engineering DepartmentFaculty of Engineering, University of Isfahan, Isfahan, IR

Abstract

Neural micro-probing not only allows us to access the brain signals, it is also one of the key tools to achieve a better understanding of the fundamental mechanisms of the brain and nervous system. This knowledge is extremely essential to implement complex neural prosthetics. Considering the importance of the size, power consumption, and accuracy, in this Paper, a compact, low-power eight-channel implantable neural recording microsystem is presented. To this end, Time Division Multiplexing (TDM) method is used for multiplexing 8 input channels. Thus, only one Analog to Digital Converter (ADC) block is used, resulting in a small circuit size and low power consumption. Also, a new structure of Amplitude-Shift Keying (ASK) modulation technique with simple configuration and low power consumption is proposed and applied. This system is designed in TSMC 0.18 μm CMOS technology with 1.8 V power supply and simulated with HSPICE. The total power consumption of the system is measured to 2 mW. Neural signals recorded from auditory cortex of a guinea pig are used as the inputs of the eight channels of the system. Total RMS error between inputs and outputs caused by the system is 2.8%.

Keywords

ASK Modulation, Implantable Microsystems, Multichannel Neural Recording, Time Division Multiplexing

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