In a biopotential monitoring system, the sensors, the front end circuit, microprocessor, digital signal processor and transmitter are important blocks. The front end circuit is capable of amplifying and conditioning the biosignal. The power requirement of a biopotential monitoring system depends on the individual blocks present in the system. Direct reduction of the power is not possible in the conventional instrumentation amplifier. The conventional instrumentation amplifier is not suitable for portable applications because it consumes much power and has a low common mode rejection ratio (CMRR). To optimize the power consumption and simplify the system architecture, the front end system adopts two-stage amplifiers. A current-balancing instrumentation amplifier approach that amplifies a biosignal is proposed to improve the noise performance and CMRR and minimize the area, power consumption, and cost. In this CBIA design, passive component mismatch is minimized. To obtain an ECG signal, the output of an instrumentation amplifier signal is further processed by high pass, low pass and notch filters to eliminate muscular noise, motion artefacts and power line interference. The resultant signal is interfaced to a personal computer through a USB/SPI interface after the conversion of the analogue biosignal into digital signals.

中文翻译：

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采用常规和电流平衡方法的生物电位放大器用于胎儿心电图监测

在生物电势监测系统中，传感器、前端电路、微处理器、数字信号处理器和发射器是重要的模块。前端电路能够放大和调节生物信号。生物电势监测系统的电源需求取决于系统中存在的各个模块。传统仪表放大器无法直接降低功率。传统的仪表放大器不适合便携式应用，因为它消耗大量功率并且具有低共模抑制比 (CMRR)。为了优化功耗和简化系统架构，前端系统采用两级放大器。提出了一种放大生物信号的电流平衡仪表放大器方法，以提高噪声性能和 CMRR，并最大限度地减少面积、功耗和成本。在这种 CBIA 设计中，无源元件失配被最小化。为了获得 ECG 信号，仪表放大器信号的输出由高通、低通和陷波滤波器进一步处理，以消除肌肉噪声、运动伪影和电力线干扰。在将模拟生物信号转换为数字信号后，产生的信号通过 USB/SPI 接口连接到个人计算机。低通和陷波滤波器可消除肌肉噪音、运动伪影和电源线干扰。在将模拟生物信号转换为数字信号后，产生的信号通过 USB/SPI 接口连接到个人计算机。低通和陷波滤波器可消除肌肉噪音、运动伪影和电源线干扰。在将模拟生物信号转换为数字信号后，产生的信号通过 USB/SPI 接口连接到个人计算机。