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BELL SYSTEM TECHNICAL JOURNAL 



device to be measured removed in order to eliminate any possible delay- 

 distortion in the converters and filter. Figure 10 uses the measuring 



and 8 



Fig. 11 — Photograph of apparatus used in the measuring circuits shown in Figs. 5 



circuit of Fig. 8 rather than that of Fig. 5 because it was found that small 

 variations in the transit time in microwave amplifiers cause small variations 

 in the phase shift which are the same at all frequencies in the band. These 



