FERRITES IN Ml( li«)\\ \\ t, \ I'FLICATIONR 



1355 



400 800 1200 



1600 2000 2400 2800 3200 

 APPLIED FIELD IN OERSTEDS 



3600 4000 4400 4800 



Fig. 12 — Ellipticity versus applied field as observed and as calculated from 

 the data of Fig. 11. 



tions are shown in Fig. 11. The resultant eUipticity in db is calculated 

 from the relation 



A = 20 logio 



E+ + E. 



E+ — E. 



(18) 



where E± are the rms values of the circular components. This result is 

 shown by the solid line in Fig. 12, and the ellipticity as measured by the 

 set-up of Fig. 10(a) is shown by the dashed line. The agreement between 

 these two curves is quite good if we consider that the accuracy of meas- 

 uring each circular component is no better than ±0.05 db so that in the 

 regions where the two circular components are actually equal the cal- 

 culated ellipticity can vary from infinity down to 52 db, while the signal 

 to noise ratio of the equipment limits the measured ellipticity to 50 db. 



