. The Bell System technical journal . STEM TECHNICAL JOURNAL, JULY 1956 plotted the distribution predicted from Fig. 9(b). The RF losses in the4,000-mc tube were not neghgible, and probably account for slightlysmaller power output and greater proportion of higher velocity electrons. COMPARISON WITH COMPUTED CURVES Non-linear calculations of traveling wave tube behavior have beenmade by Tien, Walker and Wolontis and by Tien^ covering the sameregion of parameter values as is reported here. In Figs. 2, 3, 4 and 9 areshown some of their data on our coordinates. The similarity of theresults over mu
. The Bell System technical journal . STEM TECHNICAL JOURNAL, JULY 1956 plotted the distribution predicted from Fig. 9(b). The RF losses in the4,000-mc tube were not neghgible, and probably account for slightlysmaller power output and greater proportion of higher velocity electrons. COMPARISON WITH COMPUTED CURVES Non-linear calculations of traveling wave tube behavior have beenmade by Tien, Walker and Wolontis and by Tien^ covering the sameregion of parameter values as is reported here. In Figs. 2, 3, 4 and 9 areshown some of their data on our coordinates. The similarity of theresults over much of the range is rather reassuring. It is interesting thatin order to make the computations it was necessary to assume two spacecharge factors, just as was found experimentally. There are, however,some significant differences: 1. In general, the computed values give a higher ^alue of efliciencythan is measured, by about 25 per cent. Thus, the computations indicate rwm(m^ ^ Hill zero signalcharacteristic: IDEAL ^>4 MEASURED ^j II. l( -400 0 400 800 STOPPING GRID VOLTAGE I1200 ■ F^^ A ZZ. ^^^\^^ current versus stopping potential. The oscilloscope curveIS tor a 4,0n0-mc tube, and the other that predicted from the scale model meas-urements. By integrating current as a function of velocit v for Figs. 7-10 stoppingpotential distributions can be deduced for other conditions NATUEE OF POWER SATURATION IN TRAVELING WAVE TUBES 865 c (.0 • ^ • \ \ ,j .. ^, \\S V 7ro Fig. 16 — Efficiency versus 7ro for small QC. The dashed curve is proportionalto the amount of beam current in the circuit field strength having at least 85 percent of the intensity at the edge of the beam. This illustrates the fact that forlarge beams only the edge of the beam is effective. that with the reasonable vahies of QC = .25 and 7ro = {kr = ),the efficiency would be about , whereas the measured value is The largest dis
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
