Obeid Iyad, Nicolelis Miguel A L, Wolf Patrick D
Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
J Neurosci Methods. 2004 Feb 15;133(1-2):27-32. doi: 10.1016/j.jneumeth.2003.09.024.
We present the design and testing of a 16-channel analog amplifier for processing neural signals. Each channel has the following features: (1) variable gain (70-94 dB), (2) four high pass Bessel filter poles (f(-3 dB)=445 Hz), (3) five low pass Bessel filter poles (f(-3 dB)=6.6 kHz), and (4) differential amplification with a user selectable reference channel to reject common mode background biological noise. Processed signals are time division multiplexed and sampled by an on-board 12-bit analog to digital converter at up to 62.5k samples/s per channel. The board is powered by two low dropout voltage regulators which may be supplied by a single battery. The board measures 8.1 cm x 9.9 cm, weighs 50 g, and consumes up to 130 mW. Its low input-referred noise (1.0 microV(RMS)) makes it possible to process low amplitude neural signals; the board was successfully tested in vivo to process cortically derived extracellular action potentials in primates. Signals processed by this board were compared to those generated by a commercially available system and were found to be nearly identical. Background noise generated by mastication was substantially attenuated by the selectable reference circuit. The described circuit is light weight and low power and is used as a component of a wearable multichannel neural telemetry system.
我们展示了一种用于处理神经信号的16通道模拟放大器的设计与测试。每个通道具有以下特性：(1)可变增益(70 - 94 dB)，(2)四个高通贝塞尔滤波器极点(f(-3 dB)=445 Hz)，(3)五个低通贝塞尔滤波器极点(f(-3 dB)=6.6 kHz)，以及(4)带有用户可选择参考通道的差分放大，以抑制共模背景生物噪声。处理后的信号通过板载12位模数转换器进行时分复用和采样，每个通道最高可达62.5k样本/秒。该板由两个低压差稳压器供电，可由单个电池供电。该板尺寸为8.1 cm x 9.9 cm，重50 g，功耗高达130 mW。其低输入参考噪声(1.0微伏(RMS))使得处理低幅度神经信号成为可能；该板在体内成功测试，用于处理灵长类动物皮质衍生的细胞外动作电位。将该板处理的信号与市售系统产生的信号进行比较，发现几乎相同。咀嚼产生的背景噪声被可选择的参考电路大幅衰减。所描述的电路重量轻、功耗低，用作可穿戴多通道神经遥测系统的一个组件。
