Multielectrode arrays are used broadly for neural recording, both in vivo and for ex vivo cultured neurons. In most cases, recording sites are passive electrodes wired to external read-out circuitry, and the number of wires is at least equal to the number of recording sites. We present an approach to break the conventional N-wire, N-electrode array architecture using graphene active electrodes, which allow signal upconversion at the recording site and sharing of each interface wire among multiple active electrodes using frequency-division multiplexing (FDM). The presented work includes the design and implementation of a frequency modulation and readout architecture using graphene FET electrodes, a custom integrated circuit (IC) analog front-end (AFE), and digital demodulation. The AFE was fabricated in 0.18 $\mu \text{m}$ CMOS; electrical characterization and multi-channel FDM results are provided, including GFET-based signal modulation and IC/DSP demodulation. Long-term, this approach can simultaneously enable high signal count, high spatial resolution, and high temporal precision to infer functional interactions between neurons while markedly decreasing access wires.

中文翻译：

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用于神经传感器应用的石墨烯有源电极的频分复用

多电极阵列广泛用于神经记录，无论是体内并且对于离体培养的神经元。在大多数情况下，记录点是连接到外部读出电路的无源电极，导线的数量至少等于记录点的数量。我们提出了一种使用石墨烯有源电极打破传统 N 线、N 电极阵列架构的方法，该方法允许在记录位置进行信号上转换，并使用频分复用 (FDM) 在多个有源电极之间共享每个接口线。所展示的工作包括使用石墨烯 FET 电极、定制集成电路 (IC) 模拟前端 (AFE) 和数字解调设计和实现频率调制和读出架构。AFE 在 0.18 中制造 $\mu \text{m}$CMOS；提供了电气特性和多通道 FDM 结果，包括基于 GFET 的信号调制和 IC/DSP 解调。从长远来看，这种方法可以同时实现高信号计数、高空间分辨率和高时间精度，以推断神经元之间的功能相互作用，同时显着减少接入线。