A biphasic integrate-and-fire system

A neuronal recording system for brain-machine interfaces (BMI) based on asynchronous biphasic pulse coding is described. It demonstrates the first step in the development of a completely implanted wireless solution with a fully integrated circuit architecture. A recording experiment comparing, in parallel, a commercial recording system (Tucker-Davis technology (TDT)) and the UF´s custom solution (FWIRE) is set up to compare performance. The novel aspect of the UF system is that the analog signal is represented by an asynchronous pulse train, which provides a low-power, low-bandwidth, noise-resistant means for coding and transmission. Taking advantage of neural firing features, the pulse-based approach uses only 3 K pulses/second to record a 25 kHz bandwidth signal from a hardware neural simulator.