Frequency shift of two-dimensional real coefficient zero phase FIR digital filters
Pavel Zahradník, Rolf Unbehauen · 2002
The paper concerns the frequency shift of the frequency response of two-dimensional (2-D) real coefficient zero phase finite impulse response (FIR) digital filters. Three types of the frequency shift are considered. The frequency shift allows one to move the passband of the filter in the frequency plane. By this way useful frequency transformations, e.g. lowpass to bandpass or lowpass to high-pass filter are easily achievable. The frequency shift is performed in purely analytical form. Formulas describing the mutual relation between the original impulse response and the transformed one are derived. The frequency shift is used in fast (re)design of 2-D FIR filters. The application in adaptive filtering is advantageous. Some examples are included. Side-effects of the frequency shift are mentioned.