Figure 8.12 Adaptive system identification results
4. Verifythe adaptation process byviewing how the adaptive filter coefficients are
adjusted. Record the steady-state values of w [],and plot the magnitude responses of
the adaptive filter and the unknown system. Save the adaptive filter coefficients,
and compare them with the unknown system coefficients given in the file
LP_coef.dat.
5. Adjust step size m, and repeat the adaptive system identification process. Observe
the change of the system performance.
6. Increase the number of the adaptive filter coefficients to N0 64, and observe the
system performance.
7. Reduce the number of the adaptive filter coefficients to N0 32, and observe the
system performance.
8.7.2 Experiment 8B ± Adaptive Predictor Using the Leaky LMS
Algorithm
As shown in Figure 8.7, an adaptive predictor receives the primarysignal that consists
of the broadband components v(n) and the narrowband components s(n). An adaptive
system can separate the narrowband signal from the broadband signal. The output of
the adaptive filter is the narrowband signal yn % sn. For applications such as spread
spectrum communications, the narrowband interference can be tracked and removed by
the adaptive filter. The error signal, en % vn, contains the desired broadband signal.
390
ADAPTIVE FILTERING