Determination of a low-order system model using an adaptive technique

An adaptive delay filter is used to model an unknown system. However, a low-order model is computed instead of a complete model. To illustrate the technique, an infinite impulse response (IIR) bandpass filter is modeled with a finite impulse response (FIR) approximation. Using the standard adaptive filter to model an IIR system requires a large filter, but an adaptive delay filter can do very well with only a few elements. Computer simulation results in the modeling process are included for both the adaptive delay filter and the standard adaptive filter using the least-mean-square (LMS) algorithm.<>