Faculty of Advanced Technology, University of Glamorgan, Pontypridd, UK.
Physiol Meas. 2011 Jul;32(7):917-26. doi: 10.1088/0967-3334/32/7/S14. Epub 2011 Jun 7.
Magnetic induction tomography (MIT) has been proposed for the detection of cerebral oedema and haemorrhagic stroke. Achieving the required phase measurement precision for these applications is however a major technical challenge. A critical component within an MIT system is the detector amplifier and for this role an ultra-phase-stable, low noise instrumentation amplifier has been developed. The design of the amplifier is described and (i) the results of simulations and measurements of the amplifiers phase stability versus temperature and (ii) measurements of the phase noise and drift performance of the amplifier within a single-channel magnetic induction spectroscopy system are provided and discussed. For a 10 MHz signal the amplifier, with a gain of 21, displayed an average change in the measured phase of its output of just -0.1 ± 0.6 m° °C(-1) as the ambient temperature was varied between 35 and 50 °C, demonstrating a level of phase stability approaching that required for potential biomedical applications such as the detection of cerebral haemorrhage.
磁感应断层成像（MIT）已被提议用于检测脑水肿和出血性中风。然而，为这些应用实现所需的相位测量精度是一个主要的技术挑战。在 MIT 系统中，一个关键的组件是探测器放大器，为此，已经开发出了一种超相位稳定、低噪声仪表放大器。本文介绍了该放大器的设计，并提供和讨论了（i）放大器的相位稳定性对温度的模拟和测量结果，以及（ii）在单通道磁感应光谱系统中测量放大器的相位噪声和漂移性能。对于 10 MHz 的信号，增益为 21 的放大器在环境温度在 35 至 50°C 之间变化时，其输出的测量相位仅平均变化 0.1±0.6m°°C(-1)，显示出接近潜在生物医学应用所需的相位稳定性水平，例如检测脑出血。
