Delta–Sigma Sigma Encoder for Low Low-Power Wireless Bio-Sensors Sensors Using Ultrawideband Impulse Radio
Abstract: This brief presents a systematic method to reduce the power consumption of a wireless sensor node for sensing biomedical signals. The design combines the delta–sigma sigma modulator (DSM), the ultrawideband impulse radio (UWB-IR), (UWB and the proposed xnor-delay-bas based ed encoder/decoder, which replaces the decimation filter. The encoder and decoder for both the first first- and second-order order DSMs are presented. The clock synchronization problem is solved by using an asynchronous UWB-IR. IR. The effects of window length, the order of delta–sigma sigma modulation, and the oversampling ratio are studied by simulation using neural and electrocardiography signals. Based on the simulation results, the proposed method can save power by 50% compared to the system with decimation filters, and 53% compared to the system without the proposed encoder.