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BELL SYSTEM TECHNICAL JOURNAL 



designed for gradual cut-off. In each case the nominal band width 

 was taken to be the same as that for the aperture effect alone, namely, 

 the frequency at which the loss is 7.8 decibels greater than at low fre- 

 quency. The addition of a low-pass filter could thus be considered 



— 2 



100 200 300 400 500 600 700 800 



FREQUENCY OF VIDEO SIGNAL IN KILOCYCLES PER SECOND 



900 



Fig. 8 — Amplitude-frequency characteristics of the television system used for correlat- 

 ing the motion picture projection with a television image. 



equivalent to an increase in the length of each of the scanning apertures 

 in the ratio of the nominal band widths, as illustrated by the dotted 

 curves. 



The results of the comparison were as follows. The number of 

 figures of confusion in the area of the frame was reckoned by dividing 

 the entire area of the television frame, including the blank portion and 



