NEGATIVE FEEDBACK 



415 



It is assumed that a constant signal level is maintained by an in- 

 crease in modulation level up to a point corresponding to the factor Fi. 

 Beyond this point the modulation remains fixed while the feedback 



FEEDBACK IN DECIBELS 



Fig. 3 — Theoretical manner in which components of receiver output are modified 

 by feedback. Modulation level at transmitter is assumed to be increased by the 

 feedback factor up to point P, and subsequently to remain fixed. 



factor is increased to FiF^. Since signal and noise levels have been 

 expressed in terms of power, distortion levels are similarly expressed. 



