ABSTRACT
This chapter outlines the signal flow graph (SFG) method of characterizing a linear network. It describes way of using the SFG technique to synthesize an active filter. Instead of starting with a normalized passive filter, one can also construct a leapfrog-type SFG based on the unnormalized passive filter. If a doubly terminated passive filter has a shunt reactance at the source end and a series reactance the load end, then its dual network has a series reactance at the source end and a shunt reactance at the load end. For doubly terminated Butterworth and Chebyshev low-pass filters of odd orders, the passive filter either has series reactances or shunt reactances at both ends. The technique, when applied to a low-pass filter having an elliptic response or an inverse Chebyshev response will require the use of some differentiators.
