MV's DSP ArticlesMatched OnePole Digital Shelving Filters
Onepole shelving filters with magnitude response matching the analog counterpart. A New Reverse IIR Filtering Algorithm
Straight and timereversed filters may be combined to form linear phase filters. Examples include a LinkwitzRiley crossover and a Hilbert filter. Recursive Filters in Image Processing
Recursive filters in 2D, with examples of isotropic blurs, directional blurs and notch filters. Matched Second Order Digital Filters
Biquad filters with magnitude response matching the analog counterpart for lowpass, bandpass, highpass, and peaking EQ prototypes. A New Recursive Quadrature Oscillator
A recursive, stable, lowfrequency accurate, equiamplitude quadrature oscillator  the only one I am aware of which comprises these features. Frequency Estimation from Two DFT Bins
Derivation of an exact (in the absence of noise) frequency estimation from two Fourier amplitudes.
