IEEE Trans Biomed Circuits Syst. 2010 Oct;4(5):274-80. doi: 10.1109/TBCAS.2010.2051438.
We describe the design and development of an optoelectronic lock-in amplifier (LIA) for optical sensing and spectroscopy applications. The prototype amplifier is fabricated using Taiwan Semiconductor Manufacturing Co. complementary metal-oxide semiconductor 0.35-μm technology and uses a phototransistor array (total active area is 400 μm × 640μm) to convert the incident optical signals into electrical currents. The photocurrents are then converted into voltage signals using a transimpedance amplifier for subsequent convenient signal processing by the LIA circuitry. The LIA is optimized to be operational at 20-kHz modulation frequency but is operational in the frequency range from 13 kHz to 25 kHz. The system is tested with a light-emitting diode (LED) as the light source. The noise and signal distortions are suppressed with filters and a phase-locked loop (PLL) implemented in the LIA. The output dc voltage of the LIA is proportional to the incident optical power. The minimum measured dynamic reserve and sensitivity are 1.31 dB and 34 mV/μW, respectively. The output versus input relationship has shown good linearity. The LIA consumes an average power of 12.79 mW with a 3.3-V dc power supply.
我们描述了一种用于光学传感和光谱应用的光电锁相放大器 (LIA) 的设计和开发。该原型放大器是使用台湾积体电路制造公司的互补金属氧化物半导体 0.35-μm 技术制造的，使用光电晶体管阵列（总有效面积为 400 μm × 640μm）将入射光信号转换为电流。然后，使用跨阻放大器将光电流转换为电压信号，以便后续通过 LIA 电路进行方便的信号处理。LIA 经过优化，可在 20-kHz 调制频率下工作，但在 13 kHz 至 25 kHz 的频率范围内也可工作。该系统使用发光二极管 (LED) 作为光源进行测试。通过在 LIA 中实现滤波器和锁相环 (PLL)，可以抑制噪声和信号失真。LIA 的输出直流电压与入射光功率成正比。测量得到的最小动态储备和灵敏度分别为 1.31 dB 和 34 mV/μW。输出与输入的关系表现出良好的线性度。LIA 在 3.3-V 直流电源下平均消耗 12.79 mW 的功率。
