44 



THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1951 



Figure 6 shows the results obtained using a special test signal for five 

 different PCM systems. The five PCM systems are those which result for 



ONE DIGIT 



TWO DIGITS 



'^^J? 



THREE DIGITS 



FOUR DIGITS 



FIVE DIGITS ORIGINAL 



Fig. 8~Test signal, model: one to five-digit transmission. 



one digit, for two digit, for three, four and five-digit transmission. The test 

 signal for these pictures was an electrical saw tooth wave derived from the 



