1330 THE BELL SYSTEM TECHXICAL JOURNAL, NOVEMBER 1954 



This "something" consists of using the large negative transient voltage 

 generated at the plate of tube a resulting from the application of a posi- 

 tive pulse to its grid. This transient, shown at (c) drives the grid of b 

 rapidly and heavily negative, thereby forcing the k relay to release. The 

 remainder of the pulse-correcting action consists in using this same 

 transient to delay the reoperation of the r relay. This is accomplished by 

 storing some of the energy in the Ri Ci network. This slows the building 

 up of the voltage as shown at (e), and the relay r reoperates at (f). The 

 resultant repeated signal is shown below, where a 75-millisecond signal 

 has been pulse-corrected to 65 milliseconds, further corrections being 

 effected in the subsequent sf units. 



Dialing performance of typical signaling units is shown by graphs in 

 Figs. 14(a), (b), and (c). These curves show per cent break input plotted 

 against per cent break output for 9, 1 and 1 2 pulses per second for one 

 and 6-link operation. If the system were linear the input-output charac- 

 teristic w^ould be a 45 degree straight line. When the slope is less than 45 

 degrees there is pulse correction, and if the slope were zero with an output 

 at 60 per cent, pulse correction would be perfect. It is noted that the 

 pulse correction action improves as the speed increases and at 12 pulses 

 per second the output is nearly independent of input. 



ACKNOWLEDGEMENTS 



The success of this project is the result of contributions by many 

 people, and all cannot be named specifically. However special mention 

 should be made of F. A. Hubbard, who designed the equipment arrange- 

 ments of the 2,600-cycle system and W. W. Fritschi, C. W. Lucek, R. 0. 

 Soffel and A. K. Schenck who made important contributions to the cir- 

 cuit design. 



REFERENCES 



1. J. J. Pilliod, Fundamental Plans for Toll Telephone Plant, B. S.T.J. , 31, pp. 



832-850, Sept., 1952. 



2. F. F. Shipley, Automatic Toll Switching Systems, B.S.T.J., 31, pp. 860-882, 



Sept., 1952. 



3. C. A. Dahlbom, A. W. Horton, Jr., and D. L. Moody, Application of Multi- 



frequency Pulsingin Switching, A.I.E.E. Transactions, 68, pp. 392-396, 1949. 



4. H. Fletcher, Speech and Hearing, Van Nostrand. 



