Page 219 - Mechanical Engineers' Handbook (Volume 2)

208 Signal Processing

determine the principal angle on each part and the accumulated phase shift by summing the
parts.

4.3 Comparison of FIR and IIR Filters
There are various factors when deciding on a particular filter for a given application. Table
3 summarizes these.

5 EXTRACTING SIGNAL FROM NOISE
The PSD of white noise is uniformly distributed over all frequencies. Therefore, it is possible
to detect the PSD signature of a signal corrupted by white noise by inspecting spectral
components that rise above some baseline. From this we can design a matching filter to
optimally extract the signal from the noise. Figures 11 and 12 illustrate this procedure.

REFERENCES
1. W. Press, B. Flannery, A. Teukolsky, and W. Vetterline, Numerical Recipes in C, Cambridge University
Press, Cambridge, UK, 1988.
2. T. Parks and C. Burrus, Digital Filter Design, Wiley, New York, 1987.
ˇ
3. M. Vlcek and R. Unbehauen, ‘‘Analytical Solutions for Design of IIR Equiripple Filters,’’ IEEE
Transactions on Acoustics, Speech, and Signal Processing 37(10) (October 1989).
4. S. Marple, Digital Spectral Analysis with Applications, Prentice-Hall, Englewood Cliffs, NJ, 1987.
5. A. Oppenheim and R. Schafer, Digital Signal Processing, Prentice-Hall, Englewood Cliffs, NJ, 1975.