Hardware-oriented algorithm for phase synchronization analysis of biomedical signals

Analysis of phase synchronization of biomedical signals is one of the essential processes in not only laboratories but also clinical practice such as prediction of seizures of epilepsy. To realize portable closed-loop systems with neural stimulators and recorders, reducing latency caused by analysis of phase synchronization is one of the fundamental points. This paper proposes a less-latency and hardware-oriented calculation algorithm for mean phase coherence (MPC) that is an indicator of the phase synchronization with the same accuracy compared with the conventional calculation method. With the trigonometric addition theorem and inner product, the proposed method uses only addition, multiplication, and reciprocal square root to calculate the MPC, and eliminates trigonometric functions from the definition equation of the MPC. From evaluation results, the proposed method can reduce the processing time by about 20% with a general purpose processor. Regarding products of the throughput and gate counts, a hardware implementation of the proposed method improves efficiency by about 30% compared with the conventional.