Optimal Testing of Digitally Assisted Adaptive RF Systems

Testing of adaptive analog/RF systems is challenging due to the fact that any test procedure must ensure that the system adapts correctly to external perturbations (process, workload) without incurring the excessive test time associated with iterative tuning procedures. This problem is made worse by the increased number of adaptation settings ("tuning knob values") and the requirement of measuring specifications at all of these settings. In this paper, a new test technique is proposed that allows the closed loop performance of the adaptation procedure to be predicted from a set of open-loop tests. The optimal knob settings where the system should be tested in open-loop are found using a gradient based search algorithm and optimized multitone test signals are generated such that the error in performance prediction across different tuning knob settings is minimized. The results of these tests are then mapped to the performance of the adaptive system which is validated implicitly without incurring large testing and tuning costs. Simulation results and hardware measurement results prove the validity of the proposed technique.