Robustness and Noise Voltage Analysis in Two Photometer Circuits

In this paper, a photometer circuit based on a robust two degrees-of-freedom controller is presented. Here, in order to improve the disturbance rejection performance of a conventional photometer circuit based on a basic current-to-voltage converter connection, a novel circuit based on both positive and negative feedback compensations was designed. The photometer circuit designed in this paper is robust against disturbances on the photodiode parameters, and the results showed that the robust photometer circuit is superior to the nonrobust one. The results were satisfactory and showed the importance of applying robust control techniques to the design of photometer circuits.