Libfilth

Libfilth - (c) 2004 Anders Johansson

Description

Libfilth is a library for designing, analysing, transforming and executing digital FIR and IIR filters. Several examples of how to use the library are found in the manual. The library is available under the GPL, except for the file qld.c, see COPYING.

For installation see INSTALL.

The filter design methods include:

• FIR filter with linear-phase, least-squares design.
• FIR filter with complex specification, least-squares Design.
• FIR filter with linear-phase, minimax-design using linear programming.
• FIR filter with linear-phase, minimax-design using Remes algorithm.
• FIR filter with minimum-phase and optimal amplitude.
• FIR filter with complex specification, minimax-design.
• FIR filter with group delay constraints.
• FIR optimal window using quadratic programming.
• FIR filter with minimum-phase by spectral factorisation.
• FIR filter design by cepstrum technique.
• Analog filter design Bessel-Thomson, Butterworth, Chebyshev type I, II and Elliptic function filter.
• Transformation of analog to analog and analog to digital filters.
• All-pass realization of IIR filters.
• FIR half-band filters.
• DFT filterbanks and parallel DFT filterbanks design and implementation.
• Analysis functions for calculating the properties if analog, IIR and FIR filters.

Download

Reference manual http://www.its.bth.se/staff/ajh/manual.pdf
API Reference http://www.its.bth.se/staff/ajh/libfilth/api.pdf
Source http://www.its.bth.se/staff/ajh/libfilth/libfilth.tar.gz

Todo

Remove dependency on other libraries (work begun) and find GPL compatible implementation of quadratic programming solver.

History

Version 0.1 released 2004-04-10

The first 13 design methods were written by Anders Johansson in 2003-2004 as part of course in advanced digital filter design at the Blekinge Institute of Technology in Sweden.

DFT Filterbanks were added for fun, at the release date it was the only properly debugged part of the library.

Version 0.2 released 2004-04-26

IIR Filter design debugged, problems with passband gain errors for Elliptic and Chebyshev fixed. A new design method for analog Bessel-Thomson filter added.

Version 0.3 released 2004-05-13

IIR Filter transformation added and analog filter representation reworked. Allpass realisation of IIR filter debugged.

Version 0.4 released 2004-05-23

Doxygen generated API documentation added. Major cleanup of unused functions and spell check of all source files.

Submitting patches and complaints

diff -Naur > patch.diff mail it to me