TDL for Parallel Processing

When multiplies and additions can be performed in parallel, the computational complexity of a tapped delay line is ${\cal O}(1)$ multiplies and ${\cal O}(\lg(K))$ additions, where $K$ is the number of taps. This computational complexity is achieved by arranging the additions into a binary tree, as shown in Fig. 1.15 for the case $K=4$.

Figure 1.15: An example Tapped Delay Line (TDL), with additions organized into a binary tree for maximized parallel computation.