A Clockless Method of Flicker Noise Suppression in Continuous-Time Acquisition of Biosignals

This paper presents a novel chopping method allowing suppression of 1/f flicker noise in continuous-time acquisition systems without the need for a fixed-frequency clock, stochastically deriving the chopping signal from the input and hence achieving completely signal-dependent power consumption. The method is analysed, its basis of operation explained and a proof-of-concept implementation presented alongside simulated results demonstrating an increase in achieved SNR of more than 8 dB during acquisition of ECG, EAP and EEG signals.

[1]  Jan M. Rabaey,et al.  A 0.013mm2 5μW DC-coupled neural signal acquisition IC with 0.5V supply , 2011, 2011 IEEE International Solid-State Circuits Conference.

[2]  Simha Sethumadhavan,et al.  Energy-Efficient Hybrid Analog/Digital Approximate Computation in Continuous Time , 2016, IEEE Journal of Solid-State Circuits.

[3]  C. B. Wang.  A 20 bit 25 kHz delta sigma A/D converter utilizing frequency-shaped chopper stabilization scheme , 2000, Proceedings of the IEEE 2000 Custom Integrated Circuits Conference (Cat. No.00CH37044).

[4]  V. Gilja,et al.  Signal Processing Challenges for Neural Prostheses , 2008, IEEE Signal Processing Magazine.

[5]  J. Alvin Connelly,et al.  A noise-based IC random number generator for applications in cryptography , 2000 .

[6]  Yingchieh Ho,et al.  A 0.09 $\mu$ W Low Power Front-End Biopotential Amplifier for Biosignal Recording , 2012, IEEE Transactions on Biomedical Circuits and Systems.

[7]  Timothy G. Constandinou,et al.  Continuous-Time Acquisition of Biosignals Using a Charge-Based ADC Topology , 2018, IEEE Transactions on Biomedical Circuits and Systems.

[8]  Ralf Bousseljot,et al.  Nutzung der EKG-Signaldatenbank CARDIODAT der PTB über das Internet , 2009 .

[9]  Menglian Zhao,et al.  A capacitively-coupled biomedical instrumentation amplifier employing chopping and auto-zeroing , 2012, 2012 IEEE Biomedical Circuits and Systems Conference (BioCAS).

[10]  Gabor C. Temes,et al.  Circuit techniques for reducing the effects of op-amp imperfections: autozeroing, correlated double sampling, and chopper stabilization , 1996, Proc. IEEE.

[11]  Yan Liu,et al.  Event-driven processing for hardware-efficient neural spike sorting , 2018, Journal of neural engineering.

[12]  P. K. Chan,et al.  A CMOS analog front-end IC for portable EEG/ECG monitoring applications , 2005, IEEE Transactions on Circuits and Systems I: Regular Papers.

[13]  F. Marvasti.  Nonuniform sampling : theory and practice , 2001 .

[14]  N. Birbaumer,et al.  BCI2000: a general-purpose brain-computer interface (BCI) system , 2004, IEEE Transactions on Biomedical Engineering.