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BELL SYSTEM TECHNICAL JOURNAL 



MARGINAL PULSE TO PEAK INTERFERENCE (NOISE) RATIO IN DECIBELS 

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AUDIO SIGNAL-TO-NOISE RATIO IN DECIBELS 



Fig. 15 — PCM-AM; performance with respect to number of steps. Relations between 

 bandwidth and audio signal-to-noise ratio and between bandwidth and required pulse-to- 

 interference ratio for 1000 4-kc channels. 



permitted by the system, versus bandwidth for three different audio signal- 

 to-noise ratios. The lower boundary of the curves corresponds to binary 

 PCM while the left-hand boundary corresponds to the other extreme, namely 



