. The Bell System technical journal . case was quickly dropped out because ofbeing below the slicing level has now come up above the slicing leveland so builds up to full amplitude after only a few trips through theregenerator. Note that in the cases shown in Figs. 4 and 5 discriminationagainst unwanted pulses has been purely on an amplitude basis sincethe gate has been unblocked to pulses with amplitudes above the slicinglevel whenever one of these distiubing pulses was present. For Fig. 6A conditions are the same as for Fig. 4A except that an ad-ditional pulse has been added to simulate inte
. The Bell System technical journal . case was quickly dropped out because ofbeing below the slicing level has now come up above the slicing leveland so builds up to full amplitude after only a few trips through theregenerator. Note that in the cases shown in Figs. 4 and 5 discriminationagainst unwanted pulses has been purely on an amplitude basis sincethe gate has been unblocked to pulses with amplitudes above the slicinglevel whenever one of these distiubing pulses was present. For Fig. 6A conditions are the same as for Fig. 4A except that an ad-ditional pulse has been added to simulate intersymbol noise or inter-ference. Fig. 6B indicates that after only one trip through the regeneratorthe effect of the added pulse is very small. After a few trips the effectis completely eliminated leaving a practically perfect group which con-tinues on for 24 trips as shown by Fig. 6C. For the intersymbol pulse,discrimination is on a time basis since this interference occurs at a time 76 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1956. Fig. 7 — Effect of regenerating in amplitude without retiming. A — Outputofregenerator, no timing, firt trip. B — Output of regenerator, no timing, 10th of regenerator, no timing, 23rd trip. when no gating pulse is present and hence finds the gate blocked regard-less of amplitude. To show the need for retiming the pictures shown on Figs. 7 and 8were taken. These were taken with the amplitude slicer in operation butwith the pulses not being retimed. Figs. 7A, 7B and 7C, respectively,show the output of the slicer for the first, tenth and twenty-third ten trips, there is noticeable time jitter caused by residual noisein the system; after 23 trips this jitter has become severe though pulsesare still recognizable. It should be pointed out that for this experimentno noise was purposely added to the system and hence the signal-to-noise ratio was much better than that which would probably be encoun-tered in an operating syste
Size: 1977px × 1264px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
