Low energy biomedical signal processor for wearable continuous ECG monitoring system

Abstract

A wearable ECG monitoring system is integrated on the clothes with the low energy ECG signal processor. A method to fabricate circuits on the cloth, planar fashionable circuit board (P-FCB), is proposed. Wet patterning method like screen printing as well as dry process of sputtering are used to fabricate the patterned film electrodes on various types of fabrics. Bonding and packaging of silicon chip directly on the fabric circuit board are proposed and their mechanical properties are investigated. The electrical and mechanical characteristic is measured to improve the system integration. The fabric dry electrode is implemented by P-FCB technique. An ECG signal processing algorithm with quad level vector (QLV) is proposed to reduce the system energy consumption. ECG signal processing reduces the transmission power consumption and the memory capacity. The proposed algorithm consists of the compression flow and the classification flow, and the QLV is proposed for both flows to achieve better performance with low computation complexity. The compression algorithm consisting of skeleton and the Huffman coding is applied to reduce the processing cost while maintaining the signal quality. The heartbeat segmentation and the R peak detection methods are employed for the classification algorithm. The performance is evaluated by using the MIT-BIH Arrhythmia Database, and the noise robust test is also performed for the reliability of the algorithm. Its average compression ratio is 16.9:1 with 0.641% PRD value. The accuracy performance of the R peak detection is 100% without noise and 95.63% at the worst case with -10dB SNR noise. An ECG signal processor (ESP) is designed to perform the required signal processing. The ESP performs filtering, compression, classification and encryption. The proposed ESP consists of three heterogeneous processors with specific functionalities. The QLV-based pre-processing, segmentation-based pipelined operation, processing bandwidth red...