| This thesis reports on the development of a reliable, single-chip, multichannel wireless biotelemetry microsystem intended for extracellular neural recording from awake, mobile, and small animal models. The inherently conflicting requirements of low power and reliability are addressed in the proposed microsystem at architectural and circuit levels. Through employing the preliminary microsystems in various in-vivo experiments, the system requirements for reliable neural recording are identified and addressed at architectural level through the analytical tool: signal path co-optimization.;The 2.85mmx3.84mm, mixed-signal ASIC integrates a low-noise front-end, programmable digital controller, an RI, modulator, and an RF power amplifier (PA) at the ISM band of 433MHz on a single-chip; and is fabricated using a 0.5microm double-poly triple-metal n-well standard CMOS process.;The proposed microsystem, incorporating the ASIC, is a 9-channel (8-neural, 1-audio) user programmable reliable wireless neural telemetry microsystem with a weight of 2.2g (including two 1.5V batteries) and size of 2.2x1.1x0.5cm 3. The electrical characteristics of this microsystem are extensively characterized via benchtop tests. The transmitter consumes 5mW and has a measured total input referred voltage noise of 4.74microV rms, 6.47microVrms, and 8.27microVrms at transmission distances of 3m, 10m, and 20m, respectively. The measured inter-channel crosstalk is less than 3.5% and battery life is about an hour. To compare the wireless neural telemetry systems, a figure of merit (FoM) is defined as the reciprocal of the power spent on broadcasting one channel over one meter distance. The proposed microsystem's FoM is an order of magnitude larger compared to all other research and commercial systems.;The proposed biotelemetry system has been successfully used in two in-vivo neural recording experiments: i) from a freely roaming South-American cockroach, and ii) from an awake and mobile rat. In recording from the cockroach's antennas, the small amplitude action potentials (100microV pp) on left and right antennas sensory inputs were captured wirelessly from the freely roaming subject. In recording from the Femur sections of the cockroach rear legs a variety of biopotential signals from small amplitude action potentials (microVpp) to large amplitude intramuscular EMO signals (2mVpp) were recorded wirelessly and could be attributed to state of the cockroach, i.e. walking versus standing. In recording from the hippocampus of an awake and mobile rat, the extracellular neural action potentials on eight channels were received and recovered wirelessly. |
