We have a schematic, with 3 s-parameter models in it. Its a differential Channel and the s-parameter models are 3x 3D differential Via models interconnected
by diff pair traces. an IBIS driver and an IBIS receiver are at each end of the channel. Simulations of the channel (eye ) are exactly as expected.
We've then export the circuit to an S-parameter model. After we export it, we connect the Driver and Receiver up to the exported model to check it,
only now, after simulation the eye is not the same...its actually slightly distorted with some ringing.
Does anyone know why the test circuit with the exported s-param model does not behave the same as the original circuit for which the
model was exported from?