I. Introduction
NEURAL signal recording has become standard practice in neurophysiological research and opens up a wide range of neuroprosthetic applications such as artificial retina and cochlear. The local field potential (LFP) using extracellular microelectrode represents a spatial average of neural activity and has an amplitude of 10 –5 mV and a bandwidth of 1–200 Hz [1]. Meanwhile, neural action potential (AP), associated with the individual neurons in the direct proximity of the electrode, contains the frequency signals from 100 Hz to 6 kHz [2]. Both LFP and AP are required for a neural recording system.