IEEE Signal Processing Magazine / DSP Tips and Tricks Column, vol. 30, 5, pp. 144-150, 2013
Subband signal processing is an important tool in numer-ous applications such as acoustic echo cancellation, noise reduction, signal enhancement, adaptive beam forming, and signal separation, among other applications (see, for instance, – for example applications). Subband sig-nal processing uses a filter bank to split each input signal into a set of frequency signals, each covering a fraction of the input signal bandwidth; see the illustra-tion in Figure 1. Subband processing provides an efficient way to divide and conquer tedious problems by a set of parallel and smaller subband algo-rithms. In many cases, the subband pro-cessing is performed together with decimation, which reduces the dimen-sionality of the data in the subband algorithm. The focus in this article is on temporal subband processing, i.e., time-frequency transformation, although spatial subband processing may also gain from the discussion here.