COMPARISON" OF 8IGNALLING ALPHA HKTS 



.") 1 <) 



when' fi is the rms dislaiu'c from llie origin lo tiic points of u fonfiguru- 

 tioii .1, Ri) is the distance fioni tho origin to the centroid of A, and r-z 

 is the nns distance from the i)oints of A to the centroid of A. 



In plotting points on the efhciency graph the notation A', 1) is used 

 for the best K-letter D-dimensional alphabet which has been found. 

 The arrangement of points for various A', 2 and A, 3 alphabets is given in 

 Figs. 3 and 4. In these hgures two points are joined by a straight line 

 if the distance between them is 1 (which is the value we have adopted 

 for the minimum allowed separation 2/-()). Although not shown, the origin 

 is always at the centroid of the hgure. To aid interpretation of these 

 diagrams we have included Fig. 5 which demonstrates how all the signals 

 of a typical alphabet can be generated. The functions of time shown in 



^^(^'v^'-ri?) 



s, 



2W 



2 3 



2W 2W 



Y3 



J. 



L 



T 



i_ 



Z-{6 



ITT 



2V3 



— != "2V6 



2V3 



Fig. 5 — Generation of the 4,3 code signals. 



