DKLA Y EQL'A LIZA TION OF CARRIER CIRCUITS 



191 



and the lower sideband is transmitted, the corresponding carrier frequencies 

 are 87682, 87390 and 87110 cycles, respectively. 



The required change of phase per cycle is the same as at audio frequencies, 

 but the percentage rate of change is eleven times that of the audio-frequency 

 sections operating at 8(X)0 cycles. This requires that the arms of the sec- 

 tions have proportionately stiffer reactances, higher Q's, and greater tem- 



Ll n 



r^lHP — IF- 



1-2 C2 



'-rrn^ \^ 



, ,C3 



L4 



o — ^wr^ 



L6 c 



(a) 



(b) 



(c) 



Fig. 12 — Schematic of the lattice equivalent of three tandem sections of the type 

 shown in Fig. 2. 



(0) 



(b) 



Rb-Ra 



(^) 



zl 



(C) 



Rb 



Rb-Ra 

 — VW — 



\Rb-R<i/ 



(dl 



Fig. 13 — Four-terminal equivalence showing the method of absorbing the effects of 

 dissipation in the carrier-frequency equalizer. 



perature stability. The only available elements meeting such requirements 

 are piezo-electric crystals. 



The approximate equivalent electrical circuit of a crystal is a capacitance 

 in parallel with a series combination of an inductance and capacitance, 

 and is not adaptable to the section of Fig. 2. However, when three such 

 sections in tandem are combined into a single lattice, the configuration of 



