. The Bell System technical journal . rent density as a function of phase, for a par-ticular signal input level. The velocity and current modulations at smallsignal levels check calculated values well, and it is not difficult to visu-alize the dynamics giving this pattern. Consider first the situation in the tube at small signal the input an unmodulated electron beam enters the field of an elec-tromagnetic wave moving with approximately the same velocity as theelectrons. The electrons are accelerated or decelerated depending upontheir phase relative to the wave, and soon are modu
. The Bell System technical journal . rent density as a function of phase, for a par-ticular signal input level. The velocity and current modulations at smallsignal levels check calculated values well, and it is not difficult to visu-alize the dynamics giving this pattern. Consider first the situation in the tube at small signal the input an unmodulated electron beam enters the field of an elec-tromagnetic wave moving with approximately the same velocity as theelectrons. The electrons are accelerated or decelerated depending upontheir phase relative to the wave, and soon are modulated in velocity modulation causes a bunching of the electrons near thepotential maxima (, the valleys in the inverted potential wave shown)and these bunches in turn induce a new electromagnetic wave com-ponent onto the circuit roughly in ciuadrature following the initial addition of this component gives a net field somewhat retarded fromthe initial wave and larger in amplitude. Continuation of this process. Fig. 6 — Velocity analyzer patterns. The beam sample is made to traverse anellipse at }i the signal frequency. Current density modulation appears as intensityvariation, and velocity variation as vertical deflection from the ellipse. 21 0 - I -2 2 1 0-1-2 -22 DB (a) — 5^!stt __ -_^w^^ p^^~^ 1 ^-LLfcggq 1 ! 1 i 1 ij=rr— T3aij^gj4j^^_l_j^ 1 1 -,1^^ 1 -17 DB (b) 1 ^iiTTTTT SCCl-r-^ — -=,=e^^ K ±3=-- , -^ ^^^^^^^^ <
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
