Operational Amplifier Circuits

Introduction

to Active

Filters

59

The minimum order of filter required to separate two components of

dif-

ferent frequency by a specified amount on this basis can, therefore, readily be

determined. This is achieved by the computer program Filter Order Determina-

tion (Appendix

A. 10).

However, it should be noted that high Q filters can

exceed this performance for a particular range of frequencies (see Section 5.3.3

and Figure 5-11).

High-order filters can be produced in various ways. However, in many

cases,

it is convenient to use cascaded second-order filters (as discussed in Sec-

tion 5.3) with a single first-order filter (Section 5.2) if th ...