An adaptive system for robust analog signal sample/hold

In this paper, a scheme of adaptive system producing a signal sample that is equal to the input is proposed. The system consists of a simple signal sample generator and some logic gates forming a feedback loop. The sample generator is modeled as a multi-dimensional nonlinear circuit and the digital code is applied to determine the coordinates of its operating point. By using the negative feedback loop, the code is update step by step to get the right operating point for the system to produce the sample that is the closest to the input signal. This updating process makes good use of the non-linearity of the system to have the step size variable in such a way that it is large at the beginning of the process to have a quick convergence and small at the end for a small residue error. Because the signal sample is recorded by a digital code and it can be reproduced easily without problems occurring in analog signal storage and reproduction, the system can be used for a robust analog signal sample/hold. As an example of implementing such an adaptive system, a current-sample/hold circuit has been designed and presented in the paper.