Design and architecture of multiplier-free FIR filters using periodically time-varying ternary coefficients

Multiplier-free realizations for FIR filters are proposed. The realizations use a periodically time-varying (PTV) system, flanked by simple units for upsampling and downsampling to achieve time-invariant multiplier-free FIR filter operation. The PTV system uses only ternary (0, ±1) coefficients, and the units before and after the PTV system use only power-of-two scalers. Therefore, the realizations can be implemented with only add/subtract operations. Some architectures for the proposed structures are also presented