The LTE FFT can occasionally give a mismatch between C model and HDL on the overflow output when using the Pipelined, Streaming I/O architecture with user-defined scaling.
The overflow (OVFLO0) output of the Pipelined, Streaming I/O architecture can occasionally not match the C model output. The C model behavior is always correct. Note that when overflow occurs in the Pipelined, Streaming I/O architecture, the output data will not match that from the C model, due to differing order of operations in each model.
To work around this issue, it is recommended to use a conservative scaling schedule (see documentation) which avoids overflow for all possible input data values. Where possible, the C model should be used in system simulations to verify overflow behavior and ensure overflow rates match the expected system requirements.