A wideband dual-antenna receiver for wireless recording from animals behaving in large arenas.
A wideband dual-antenna receiver for wireless recording from animals behaving in large arenas.
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DOI：
10.1109/tbme.2013.2247603
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
Ghovanloo M
中科院分区：
文献类型：
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作者：
Lee SB;Yin M;Manns JR;Ghovanloo M
提出了一种用于多通道无线植入式神经记录（WINeR）系统的低噪声宽带接收器（Rx），该系统利用脉宽调制（PWM）样本的时分复用。WINeR-6 Rx由四个部分组成：1）RF前端; 2）信号调理; 3）模拟输出（AO）; 4）现场可编程门阵列（FPGA）后端。RF前端接收403-490 MHz频带内的RF调制神经信号，带宽为18 MHz。FPGA中的移频键控（FSK）PWM解调器是一个具有304 ps分辨率的时间-数字转换器，它将模拟脉宽信息转换为16位数字样本。自动频率跟踪已在Rx中实现，以锁定在发射机（Tx）中的自激压控振荡器上。使用两个天线和两个平行的RF路径来增加无线覆盖区域。BCI-2000图形用户界面已被采用和修改，以获取，可视化，并记录恢复的神经信号在真实的时间。AO模块选择三个解复用通道，并将其转换为模拟信号，以便在示波器上直接观察。其中一个信号被进一步放大以生成音频输出，为用户提供收听正在进行的神经活动的能力。使用32通道WINeR-6 Tx对Rx性能进行的台式测试表明，在Tx-Rx距离为1.5 m时，整个系统的输入参考噪声为4.58 μVrms，分辨率为8bit，速率为640 kSps。在体内实验中，海马位置细胞的位置特异性感受野在行为实验中被绘制出来，在该实验中，大鼠在一个大的圆形轨道上完成40圈。将结果与通过商业硬连线记录系统从相同动物和相同电极组获得的结果进行比较，以验证无线记录的信号。
A low-noise wideband receiver (Rx) is presented for a multichannel wireless implantable neural recording (WINeR) system that utilizes time-division multiplexing of pulse width modulated (PWM) samples. The WINeR-6 Rx consists of four parts: 1) RF front end; 2) signal conditioning; 3) analog output (AO); and 4) field-programmable gate array (FPGA) back end. The RF front end receives RF-modulated neural signals in the 403–490 MHz band with a wide bandwidth of 18 MHz. The frequency-shift keying (FSK) PWM demodulator in the FPGA is a time-to-digital converter with 304 ps resolution, which converts the analog pulse width information to 16-bit digital samples. Automated frequency tracking has been implemented in the Rx to lock onto the free-running voltage-controlled oscillator in the transmitter (Tx). Two antennas and two parallel RF paths are used to increase the wireless coverage area. BCI-2000 graphical user interface has been adopted and modified to acquire, visualize, and record the recovered neural signals in real time. The AO module picks three demultiplexed channels and converts them into analog signals for direct observation on an oscilloscope. One of these signals is further amplified to generate an audio output, offering users the ability to listen to ongoing neural activity. Bench-top testing of the Rx performance with a 32-channel WINeR-6 Tx showed that the input referred noise of the entire system at a Tx–Rx distance of 1.5 m was 4.58 μVrms with 8-bit resolution at 640 kSps. In an in vivo experiment, location-specific receptive fields of hippocampal place cells were mapped during a behavioral experiment in which a rat completed 40 laps in a large circular track. Results were compared against those acquired from the same animal and the same set of electrodes by a commercial hardwired recording system to validate the wirelessly recorded signals.