Digital filter realisation by passive network simulation

Recently it has been shown that the LU decomposition drawn from matrix theory can be employed to derive digital circuit topologies simulating passive LCR ladders (1-2). These, so called LUD type, circuits have some advantageous properties for parallel processing while retaining the low-sensitivity of the prototypes. In this paper, the basic principle of LUD design is outlined and a frequency transformation method is introduced. This will solve the instability problem encountered in high-pass and band-stop LUD design. The same technique is applied to band-pass filters with reduced hardware cost, when compared with a direct approach. The regularity of the structures allows easily programmable application.<>