Presentation Information
[C-12-45]Adaptive Interference Cancellation Receiver Circuit for Brainwave Sensing Using the Acoustoelectric Effect
〇Ayato Mizutani1, Makoto Takamiya1, Michihiro Ide1 (1. The University of Tokyo)
Keywords:
Analog front end,CMOS Integrated circuit,In vivo sensing
We propose a receiver IC using an adaptive carrier-cancellation circuit for acoustoelectric neural sensing. Ultrasonic measurement using the acoustoelectric effect is attracting attention as a minimally invasive neural sensing method. While this method can read local activity with space resolution on the order of a few mm, suppressing interference waves caused by electric field coupling of ultrasonic signals in the reception path was a challenge. In the proposed configuration, an adaptive canceller circuit detects DC error after the TIA and injects a cancellation signal to suppress interference waves in the RF domain. This allows dynamic range requirements to be relaxed while maintaining a low-frequency passband of 10Hz or less. Simulation evaluation showed that 111dB interference-derived DC suppression, an 18.5bit relaxation of the subsequent ADC dynamic range, flat passband characteristics up to 10Hz, and NF degradation suppressed to +0.70dB can be achieved.