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 ${\cal O}(\log(K))$ 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.2.21 for the case $K=4$ .

Figure 2.21: An example Tapped Delay Line (TDL), with additions organized into a binary tree for maximized parallel computation.