The new "zero delay the easy way" provides tools for designing digital
filters based on analog prototypes, and analyzing the results, including
plotting frequency response accurately.
State Variable Filters have many desirable properties, and adapt well
to matrix form. This notebook describes the theory and provides some
measurements of error and behavior under modulation.
The lab/ directory is for experiments and explorations. This is an
IPython notebook suggesting that a matrix-based implementation of biquad
filters may be faster than the traditional method.
The sawtest.py script generates audio samples for various filter
implementations (including matrix exponential and TPT) with various
input signals and settings. It should be useful for comparing the
quality of the various implementations, even though it's pretty slow.
Raph Levien