SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The traceback hard decision memory can store up to 32768 traceback bits and there are 2(K-1) bits stored at each trellis stage. Therefore, the traceback hard decision memory can store decisions of 32768/2(K-1) symbols. The traceback soft decision memory can store up to 8192 traceback soft values and, therefore, contain up to 8192 soft decisions of 8192/2(K-1) symbols. Assume a terminated frame of length F (excluding tail bits) and a constraint length K, F and K determine whether all decisions can be stored in the traceback memories.
If the decisions do not fit in the traceback HD/SD memory, then the convergent or mixed mode is used and the original frame is segmented into sliding windows (SW) otherwise, the traceback mode is set to tailed and no segmentation is required.