Figure 1.

(a) The block diagram of the DWT pyramid algorithm. The input signal $x\left(n\right)$ is filtered recursively by a set of high-pass wavelet and low-pass scaling filters. The output of each filter is downsampled by a factor of two. (b) The block diagram of the MODWT pyramid algorithm. In MODWT, the sampling rate is the same at all levels of decomposition. However, the $(j+1)$th-level filters are upsampled by a factor of two with respect to the jth-level filters.