I'm using the Stimulus and Probe blocks in simulating the behavior of the ADAU1772. All works fine until I try and split part of the signal with the T Connection 1772 and then after some filters, sum the 2 signals with the Add block. Then, no matter what I do with the filter parameters, the probe plot stays the same. I have tested a schematic with the T Connection and no Add block (just sent each signal to a different output) and the plot changes with a change in filter specification. So it appears to be the Add block causing the problem. Unfortunately I need to simulate the overall filter behavior with multiple signals added together. How do I get the Add block to work with the Stimulus and Probe?