THE L3 SYSTEM DESIGN 



803 



I . 



I ! IMPEDANCE 



I {irregularities I 



I I 



FIXED LOSS ! 

 SHAPE 



I LOSS VARIATION 

 'WITH TEMPERATURE 



^-. 



TERMINATIONS 



DESIGN I 

 DEVIATIONS! 



CABLE LOSS 

 COMPENSATION 



BASIC 

 EQUALIZER 



ARTIFICIAL 

 LINE 



t MISALIGNMENT! 

 'COMPENSATION I 



RANDOM 

 ■n DEVIATIONS i 



•(manufacturing)! 



FIXED 

 GAIN 

 SHAPE 



RESIDUES 



INSUFFICIENT 



SHAPES 



T- 



FIXED AND MANUAL 

 DELAY SHAPES 



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REGULATING 



SHAPE 

 (AUTOMATIC) 



AUXILIARY 

 REPEATER 



VACUUM 

 TUBE 



GAIN 



VARIATIONS 



WITH 



^^'^^ i j TEMPERATURE ! I 



MANUAL 



GAIN 

 SHAPES 



AUTOMATIC 



GAIN 



SHAPES 



U o'^.^^^^r^SlFr?., I MISALIGNMENT 

 EFFECTS ' I ^Q^^"-'^^" 



MANUAL 

 GAIN SHAPES 



::j 



AUTOMATIC 

 GAIN SHAPES 



FINAL 

 MOP-UP 



I 1 SOURCE OF 



I J DEVIATION 



CD 



note: all SHAPES USED AT 



MISALIGNMENT EQUALIZER 

 ARE ALSO USED AT FINAL 

 MOP-UP POINT 



Fig. 13 — L3 coaxial system, equalization plan. 



compensate for cable loss. These equalizers will be used at every mop-up 

 point, at 40 to 120-mile intervals. 



When television is transmitted, fixed delay equalizers are used at 

 approximately loO-mile intervals. These equalizers compensate for the 

 delay distortion introduced by the cutoffs of the auxiliary repeater 

 sections. 



2.222 Manually Adjustable Equalizers 



The manually adjustable gain equalizers consist of networks whose 

 loss-frequency characteristics are related to one another by a Fourier 

 series type of representation. The number of terms of the series required 

 to meet system objectives varies with different types of mop-up points 

 and depends on the system apphcation being provided for, all-message 

 or combined message-television service. Equalizers of this type are used 

 in mop-up points at 40 to 120-mile intervals along the line. 



Manually adjustable delay equahzers are provided at approximately 

 150-mile intervals when television signals are transmitted. These equal- 



