A professor in Stanford University's Center for Computer Research in Music and Acoustics is the author of this online book on digital filters. The material is mainly geared toward musicians, but it can be useful for anyone learning about digital signal processing. Available in draft form as of March 2003, the book contains equations, theorems, and principles of filter design spread across many...

dspGuru is a site dedicated to digital signal processing (DSP) designers. It has a good collection of resources for both beginners and seasoned users. Many open-source software titles can be freely downloaded, ranging from implementations of DSP algorithms to compilers and other software development tools. Five frequently asked questions lists cover some important DSP subjects, like finite and...

Professor Andreas Spanias of Arizona State University has supervised the development of this online digital signal processing (DSP) system simulation utility. This utility has many functions that allow the user to generate various signals, create filters, and analyze the responses. Other functions include Fourier Transforms, convolution, autocorrelation, and several speech processing tools. The...

Dr. Steve Smith offers his book about digital signal processing (DSP) free, in its entirety, on this site. The DSP guide introduces the reader to the fundamentals, and then delves into digital filters, applications, and complex techniques. All 33 chapters can be downloaded individually or as a whole. The book is quite well written, with plenty of figures, graphs, and illustrations that accompany...

Released on February 25, 2002, this article from the National Academy of Sciences' Beyond Discovery online magazine "describes the development of the mathematical modeling technique known as wavelets." Used in image compression and digital signal processing, wavelet functions are important for computer graphics and animation. The article is very well organized and can be understood by anyone with...