In this work, we propose an ultra-low power highly configurable analog/mixed-signal (AMS) processor as part of a smart RF signal detection and recognition system focusing on the ISM band. The analog feature extraction approach reduces power consumption and data rate through smart feature selection. The implemented highly configurable analog circuit enables detection and recognition of various signal types across a large variety of spectrum conditions. The proposed system achieves state-of-the-art accuracy with sub-mW power consumption.