262 



BELL SYSTEM TECHNICAL JOURNAL 



Figure 12 shows the measured relative delay of a typical intermediate 

 frequency amplifier. This amphfier has a substantially flat amplitude 

 response over a band of about 12 mc centered on 65 mc. The delay dis- 

 tortion over the 10 megacycle band from 60 to 70 mc is about 10 X 10~^ 



30 



if) OC 



Z 



o 

 o 

 5^20 



10-9 



52 54 



56 



58 60 62 64 66 68 70 72 

 FREQUENCY IN MEGACYCLES PER SECOND 



74 



76 



78 



Fig. 13 — Measured relative delay of an experimental delay equalizer 



35 



30 



o 

 o 



Z20 



> 

 5 10 



X 10' 



52 



56 



58 60 62 64 66 68 70 72 



FREQUENCY IN MEGACYCLES PER SECOND 



74 



76 



78 



Fig. 14— Measured relative delay of the amplifier of Fig. 12 plus an equalizer 



seconds. Figure 13 shows the measured relative delay of a bridged T phase 

 equalizer which can be used to compensate for the distortion in the amplifier. 

 Figure 14 shows the measured relative delay for the amplifier of Fig. 12 

 and an equalizer measured together. The equalizer has reduced the delay 

 distortion over the 10 mc band from about 10-« to 10"^ seconds. These 



