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BELL SYSTEM TECHNICAL JOURNAL 



Fig. 23 — Pictures of the angle monitoring oscilloscope and the delay indicator 

 tube. The right-hand end of the sweep of the monitoring tube represents zero 

 phase. The indicated angles are 8.5 and 20.5 degrees. The MUSA branches were 

 set at these angles (<^a = 240°, 4>b = 30°) using 950 microseconds delay. GSE 

 (11,860 kilocycles) Daventry, February 21, 1936, 11:05 a.m., E.S.T. Musical 

 program. 



