A sparse matrix approach to digital filter analysis using IBM PCs

Modifications are proposed for the Digital Filter Plotting Program by Donald Brunnett. These modifications take advantage of the inherent sparsity of the nodal transmittance matrix of the digital filter analysis problem. Procedures are presented for realizing greater speed and efficiency by storing non-zero elements only and ignoring operations on zeros. Comparisons of the two versions are made and several examples are presented to demonstrate the advantages of the approach taken.