2.7 CONCLUSION

In this chapter, we studied the core of analog filter design, the normalized approximation functions. By developing these functions, we have laid the foundation for the remainder of the chapters on analog filter design as well as a good bit of digital IIR filter design. By approaching each approximation function in the same manner, and developing methods for determining exact pole and zero placement, we have simplified the job of generating the C code necessary to implement these algorithms in a clean, efficient manner. (Those who are interested in seeing more on the development of the C code can turn to Appendix D.) In the next chapter, we will finish up the analog filter design calculations by determining a technique to unnormalize the transfer functions we have just developed.