Properties of digital 1/3-octave filters implemented according to ANSI S1.11
Antonina Geras, Tomasz Starecki · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2012
The paper presents results of investigation into properties of digital filters implemented in compliance with ANSI S1.11 Standard: Octave-Band and Fractional-Octave Band Analog and Digital Filters. The discussed solutions are digital one-third-octave IIR filters with Direct Form I topology. Performed simulations showed that the filters exhibit strong problems with stability, especially in the case of low center frequency filters. Another problem clearly visible in all investigated structures was poor attenuation at the frequencies above the passband. Although the filters were implemented according to the ANSI standard, none of them met all of the requirements of the standard.