一种混合信号传输的低场核磁共振读出电路

A Low Field Nuclear Magnetic Resonance Readout Circuit Using Hybrid Signal Translation

提出了一种应用于低场核磁共振的采用混合信号传输的读出电路。该读出电路系统主要由前端放大器、接收机与后端模数转换器组成。提出的混合信号传输技术的本质在于利用相位域与电压域的混合模式检测,以及放大器与模数转换器之间的增益分配来增强线性度。采用0.18μmCMOS工艺设计,仿真结果表明,在1.2 V的电源电压下,整体电路的功耗为0.5 mW,前端放大器的输入1 dB压缩点与IIP3分别为-9.31 dBm和-5.98 dBm,接收机的等效输入噪声仅为2 nV·Hz^(-1/2)。

A readout circuit with hybrid signal translation applied to low field nuclear magnetic resonance(NMR) was proposed. The readout circuit system was mainly composed of front-end amplifiers, receivers and back-end analog-to-digital converters. The natures of the proposed hybrid signal translation technique were the linearity enhanced through hybrid mode detection of phase domain and voltage domain, as well as the gain distribution between the amplifiers and the ADC. The circuit was designed in a 0.18 μm CMOS process. The simulation results showed that the power consumption of the whole circuit was 0.5 mW at a power supply voltage of 1.2 V. The input referred 1 dB compression point and IIP3 of the front-end amplifiers were-9.31 dBm and-5.98 dBm respectively. The input referred noise of the receiver was only 2 nV·Hz^(-1/2).