MULTICHANNEL AMPLIFIERS BELOW OVERLOAD 605 



summation is obtained over all types of products but the predominant 

 order may be distinguished by the power law followed. Effects not 

 simulated are the frequency distribution of speech energy within 

 individual channels and the idle periods which occur in various 

 channels during normal operation, but these effects are minor in a 

 system with a large number of channels. The noise loading method 

 is particularly valuable on a multirepeater line, in which modulation 

 measurements made with discrete frequencies may show large varia- 

 tions with frequency because of phasing between the various sources. 

 Loading with a flat band of energy secures an average of these varia- 

 tions over the frequency range used. 



Acknowledgments 



Contributions to the solution of the various problems discussed here 

 have been made by many members of the Bell Telephone Laboratories. 

 The author wishes to take this opportunity to acknowledge his in- 

 debtedness to those of colleagues who have participated in the develop- 

 ment of the ideas here discussed." 



Other References 



Following is a list of published papers (excluding those to which reference has 

 already been made in the text) relating to various aspects of the general problem 

 discussed here: 



F. Strecker, "Nichtlineares Nebensprechen bei der gemeinsamen Ubertragung- 



mehrerer modulierten Tragerwellen," Hoch. u. Elek., 49 (1937), 5, pp. 165-171 " 

 H. Jacoby and G. Giinther, "Uber die Wahrscheinlichkeit der in Tragerfrequenz' 



Vielfachsystemen auftretenden linearen und nichtlinearen Spannungen,' 



Hoch. u. Elek., 52 (1938), 6, pp. 201-209. 

 E. Holzler, "Das Nichtlineare Nebensprechen in Mehrfach-Svstemen mit Uber- 



tragenen Tragern," Hoch. u. Elek., 52 (1938), 4, pp. 137-142. 

 H. F. Mayer and D. Thierbach, "Uber den Einfluss von Nichtlinearitat und 



Warn^erausrhen auf die Reichweite von Tragerfrequenz- Vielfach-Systemen," 



E. F. D., 48 (1938), pp. 6-12. 

 H. Tischncr, "Zur Jlerechnung und Messung nichtlinearen Verzerrungen in Trager- 



frequcnten Ubertragungs-systemen," Zeitschr. f. techn. Physik, 19 (1938), 11, 



pp. 425-429. 

 Yonezawa and Hirayama, "Relation Between the Non-Linear Distortion and the 



Crossiplk on Multiplex Transmission," Nippon Elec. Comm. Eng., June, 1938. 

 Yonezawa, "Non-I inear Distortion and Crosstalk Frequency Groups in Multiplex 



Carrier Transii.i;?-ion," Nippon Elect. Comm. Eng., September, 1938. 

 Matzumae and Voneznwa, "Equipments for Multiplex Carrier Telephony on Ultra 



Short Wave," Nippon Elect. Comm. Eng., Feb. 1939. 



