Matrix formulation: fast filter bank

The fast filter bank (FFB) describes a class of tree-structured filter banks that operate on a frequency response masking principle. Although the structure is highly regular and conveniently implemented in hardware designs, real-time software implementations lead to inefficiencies due to its branching structure. In this paper, an alternative formulation of the FFB is proposed in terms of matrix computations. This allows an efficient approach in its implementation, and significantly reduces the overall buffer memory size required. The matrix operations can be carried out using easily available highly-optimized mathematical software packages, resulting in improvements in computational speed. Savings of up to a factor of 3 in the computer time have been observed during tests on a Pentium 4 computational platform workstation.