783Chapter 23
Filters and Equalizers
by Steven McManus
23.1 Filter and Equalizer Definitions............................................................ 785
23.1.1 Pass Band.......................................................................... 785
23.1.2 Stop Band.......................................................................... 785
23.1.3 Cutoff Frequency..................................................................... 785
23.1.4 Corner Frequency.................................................................... 785
23.1.5 Bandwidth.......................................................................... 785
23.1.6 Transition Band...................................................................... 785
23.1.7 Center Frequency..................................................................... 785
23.1.7.1 Geometric Symmetry.............................................................. 785
23.1.7.2 Arithmetic Symmetry............................................................. 785
23.1.8 Order.............................................................................. 786
23.1.9 Phase Angle......................................................................... 786
23.1.10 Phase Delay........................................................................ 786
23.1.11 Group Delay....................................................................... 786
23.1.12 Transient Response.................................................................. 786
23.1.13 Minimum Phase..................................................................... 786
23.2 Passive Filters.......................................................................... 786
23.2.1 First-Order L and C Networks........................................................... 786
23.2.1.1 Capacitive Networks.............................................................. 787
23.2.1.2 Inductive Networks............................................................... 788
23.2.2 Second-Order L-Type Networks......................................................... 788
23.2.3 T and SNetworks.................................................................... 789
23.2.3.1 Low Pass....................................................................... 789
23.2.3.2 High Pass....................................................................... 789
23.2.3.3 Parallel Resonant Elements......................................................... 790
23.2.3.4 Series Resonant Elements.......................................................... 790
23.2.3.5 Bandpass....................................................................... 791
23.2.3.6 Band Reject..................................................................... 791
23.2.3.7 Ladder Networks................................................................. 791
23.2.4 Filter Design........................................................................ 791
23.2.4.1 Butterworth..................................................................... 792
23.2.4.2 Linkwitz-Riley................................................................... 792
23.2.4.3 Chebyshev I and II................................................................ 792
23.2.4.4 Elliptical........................................................................ 793
23.2.4.5 Normalizing..................................................................... 793
23.2.4.6 Scaling......................................................................... 793
23.2.5 Q and Damping Factor................................................................ 793
23.2.6 Impedance Matching.................................................................. 793
23.3 Active Filters........................................................................... 793