Dipartimento di Ingegneria Enzo Ferrari. University of Modena and Reggio Emilia, Modena (MO) 41125, Italy.
Rev Sci Instrum. 2023 Jan 1;94(1):014705. doi: 10.1063/5.0130239.
The preamplifier proposed in this paper is designed to extract weak variable photogenerated signals from a high-level continuous background ensuring low noise and high transimpedance gain. An efficient cancellation of the DC component directly at the photodetector output, exploiting a feedforward approach, allows us to properly amplify the variable signal components of interest avoiding saturation of the preamplifier. Furthermore, the large transimpedance gain allows for minimizing the effects of the noise introduced by the following stages on the signal processing chain. In the paper, we present the proposed approach and a possible circuit realization with a signal AC/DC ratio as small as 1/1000 ensuring low noise, high gain, and a considerable bandwidth. The realized preamplifier offers a Noise Equivalent Power NEP ≃ 1.12 nW, an in-band transimpedance gain of 4.4 MΩ, and a wide bandwidth from about 1 Hz up to 100 kHz, making it suitable for use in several applications both in biomedical and industrial fields.
本文提出的前置放大器旨在从高电平连续背景中提取弱变量光生信号，同时确保低噪声和高跨阻增益。通过前馈方法有效地消除光电探测器输出端的直流分量，可以对感兴趣的变量信号分量进行适当放大，避免前置放大器饱和。此外，大的跨阻增益可以最小化后续级引入的噪声对信号处理链的影响。在本文中，我们提出了这种方法，并给出了一种可能的电路实现方案，该方案在信号交流/直流比低至 1/1000 的情况下仍能保证低噪声、高增益和相当宽的带宽。实现的前置放大器具有噪声等效功率 NEP ≃ 1.12 nW、带内跨阻增益为 4.4 MΩ，以及从大约 1 Hz 到 100 kHz 的宽带宽，使其适用于生物医学和工业领域的多种应用。
