This note analyzes incoherent feedforward loops in signal processing and control. It studies the response properties of IFFLs to exponentially growing inputs, both for a standard version of the IFFL and for a variation in which the output variable has a positive self-feedback term. It also considers a negative feedback configuration, using such a device as a controller. It uncovers a somewhat surprising phenomenon in which stabilization is only possible in disconnected regions of parameter space, as the controlled systems growth rate is varied.
Download