I would like to get some ideas from the authors of the AMI specification on what the intent was when Init_Returns_Impulse = False. I would also like to get some suggestions on what the Init function should return when Init_Returns_Impulse = False. Options: - return the same thing that was sent into Init - return impulse response of the filter - return uninitialized memory (garbage or noise) It seems that either the first or second answer may be the correct one if I consider that the calculations are supposed to be done "in place", i.e. in the same memory space where the input was placed. If nothing is done, the memory will still contain the input data in that place. If something is done, like returning the filter only impulse response, we will get that in that memory space. It is hard to turn that memory space into uninitialized memory, unless we use a random number generator to do something that can mimic that effect. Thanks, Arpad ======================================================