POTENTIAL ANALOGUE METHOD OF NETWORK SYNTHESIS 



363 



(all poles) of a high-pass filter, f The contour C is shown surrounding the 

 band of interest. There are really two contours, one surrounding a band of 

 positive frequencies and another surrounding a band of negative frequencies. 

 To obtain an exact solution for the charge distribution using two contours 

 would be very troublesome. Fortunately the two contours are far enough 



3.5 



3.0 



2.5 



2.0 



0.5 



Z 2.870 



2.860 



3.0 



3.5 



4.0 



4.5 5.0 5.5 6.0 6.5 7.0 7.5 



FREQUENCY IN MEGACYCLES PER SECOND 



Fig. 25 — Curves showing phase delay of filter, equalizer and their combination. 



apart so that the charges on one produce only small effects inside the other. 



The charge distribution on the upper contour was found by replacing the 



lower contour charges by a single large pair of positive and negative charges. 



The delay to be produced by the equalizer varies slowly across the band 



t The zeros (not shown) of the filter are on the imaginary axis below the pass band. 

 They are ignored because they contribute no delay. 



