Efficient CAD tools for the coefficient optimisation of arbitrary integrated digital filters
Rajeev Jain, Joos P. L. Vandewalle, Hillarie Man · 2005
An interactive CAD methodology is presented for designing digital filters with optimised discrete coefficients. The objective is to minimise the cost of integrationC(\undertilde{a})subject to the constraint that the desired specifications on the complex frequency transfer functionH(w,\undertilde{a})are satisfied. The vector a represents the fixed coefficients in the filter network. For VLSI DSP architectures, where multiplication is implemented using software controlled or hardwired shift-and-add operations,C(\undertilde{a})is defined as the total number of non-zero bits in the discrete representation of\undertilde{a}. An accurate multiparameter analysis technique, based on the bilinear property ofH(w,\undertilde{a}), is exploited to develop numerically reliable and computationally efficient tools for function evaluation and feasible region determination. These are built into a CAD framework together with tools for computingC(\undertilde{a})and predicting the location of the minima ofC(\undertilde{a})Extremely fast optimisation strategies using this framework are demonstrated, for different filter topologies with up to 10 coefficients.