Infinite Impulse Response ( IIR ) Filter Sections
Maurice Bellanger · Digital Signal Processing · 2024
Digital filters with an infinite impulse response (IIR) are discrete linear systems which are governed by a convolution equation based on an infinite number of terms. This IIR allows for much more selective filtering functions to be obtained than with finite impulse response (FIR) filters of similar complexity. The study of the purely recursive section has been carried out in the frequency domain. The elements can be implemented by circuits which directly produce the operations represented in the expression for the transfer functions. The limitation of the coefficient wordlength means that the coefficients can have only a limited number of values. It follows, therefore, that the poles have a limited number of possible positions inside the unit circle. The introduction of the quantization device has consequences in the absence of a signal.