Systems and methods for energy-efficient measurement of neurophysiological oscillations

A system for measuring synchrony in one or more regions of a subject's brain, the system comprising:

• a signal conditioning circuit configured to:
• receive a neural signal from a neural signal source in the brain;
• and
• determine real (Re) and imaginary (Im) components of the received neural signal;
• a feature determination circuit coupled with the signal conditioning circuit and configured to:
• receive the real and imaginary components of the neural signal;
• determine, using a linear arctangent approximation algorithm, a phase of the neural signal;
• determine a magnitude of the neural signal;
• and
• determine, based on the determined phase and magnitude, synchrony metrics, wherein the feature determination circuit further comprises:
• a reciprocal lookup table configured to provide a reciprocal of a larger of the real component and imaginary component;
• a multiplication module configured to multiply an output of the reciprocal lookup table with a smaller of the real component and imaginary component to provide a fraction;
• an offset value module configured to provide an offset based on a determined quadrant of the received neural signal on the complex plane;
• a fraction sign module configured to provide a fraction sign based on the determined quadrant;
• and
• an addition module coupled with the output of the multiplication module, offset value module, and fraction sign module, and configured to add the provided offset and provided fraction, wherein the sign of the provided fraction is determined by the provided fraction sign;
• and
• a synchrony circuit coupled with the feature determination circuit and configured to:
• compare the synchrony metrics with a threshold.