Integrated continuous-time Sigma-Delta Modulator and low noise amplifier for tracheostomy tube wireless application

Abstract

This paper presents the design and experimental results of a continuous-time (CT) sigma-delta (ΣΔ) modulator and low noise amplifier (LNA) with data-weighted average (DWA) technology. A new image-reject low noise amplifier is designed for ECG communication and bio-signal wireless acquisitions. An inter-stage T-structure filter is used in the low noise amplifier design to provide 35-dB image rejection. The DWA technique is used for reducing DAC noise due to component mismatches. Experimental results show the ΣΔ modulator achieves 54-dB dynamic range, 51-dB SNR, and 48-dB SNDR over a 10-MHz signal bandwidth with an oversampling ratio (OSR) of 8, while dissipating 19.8 mW from a 1.2-V supply, which can be used for electroencephalogram (EEG) or electrocardiogram (ECG) signal acquisition systems by wireless sensor and communication. This provided sensor setup CO2 concentration detecting instruments on chip. Oxygen generator will real time to support when sensor monitor and wireless send bio-signal to doctor or health cloud.