Resolving Delay-Free Loops in Recursive Filters Using the Modified Härmä Method

Pirkle W. Resolving Delay-Free Loops in Recursive Filters Using the Modified Härmä Method. In: AES Convention 137. Audio Engineering Society; 2014. Paper 9194. Available from: https://aes.org/publications/elibrary-page/?id=17517

@inproceedings{Pirkle2014_17517,
  author = {Pirkle, Will},
  title = {{Resolving Delay-Free Loops in Recursive Filters Using the Modified Härmä Method}},
  booktitle = {AES Convention 137},
  note = {Paper 9194},
  year = {2014},
  month = oct,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=17517}
}

TY  - CPAPER
TI  - Resolving Delay-Free Loops in Recursive Filters Using the Modified Härmä Method
AU  - Pirkle, Will
T2  - AES Convention 137
M1  - Paper 9194
PY  - 2014
DA  - 2014/10/06
UR  - https://aes.org/publications/elibrary-page/?id=17517
PB  - Audio Engineering Society
LA  - en
AB  - Resolving delay-free loops in recursive filter structures has been a longstanding problem approached in several different ways including signal flow graph manipulation [1], [2] and more recently with Zavalishin’s instantaneous response technique [3],[4]. Härmä demonstrates a method for resolving delay-less loops in recursive filter structures [5] but the technique is limited to a specific generic loop topology in which the feedforward branch does not implement signal processing; all processing is implemented in one or more delay-less feedback loops. We modify Härmä’s method to accommodate filter processing in the feedforward branch and provide a step-by-step method to resolve delay-less loops in recursive filter structures. We conclude with examples including a new method of synthesizing fourth order filters.
ER  -