Does anyone know where I can learn how to code filters? I've seen a few block diagrams of digital filters (such as http://www.qsl.net/dl4yhf/speclab/filters.htm), which I could easily implement.
The problem is the coefficients. They seem completely arbitrary to me - I wouldn't have a clue about how to translate filter parameters like filter type, cutoff, resonance, etc into coefficients.
Can anyone help?