Active Band Pass Filter Product Line

This line of active band pass filters was designed by Dr. Vlasak during the time that he was studying for his doctorate. The heart of this filter was a "negative resistor". With multilpole poles, the negative resistor produces a shift in the pole locations. These poles can have imaginary components, and the pole locations are stabilized by having very active feedback gain within the negative resisitor. This design method allowed filter design by means of a computer program that generated the negative resistance value and the values of the RC components.

 

 

 

 

 

 

Various types of filters are also possible using this design method. Standard filter types are illustrated at the right. These filter types include Butterworth (also known as Maximally Flat) filter, Bessel Function, and Chebyshev.

 

 

 

 

 

Note that the Chebyshev filter produces some ripple in the passband, but very steep band edge slopes can be obtained for maximum adjacent-channel rejection. Note that any filter that has a very rectangular shape also has more transient "ringing" effects.