Tek 109 pulse generator

 

 

 

More on Tektronix 109 Reed Relay Pulse Generator

But see my article 13 years previously; "Any apparently steady field is a combination of two energy currents travelling in opposite directions at the speed of l;ight."

My letter to the author. Wakefield 2012 experiment

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IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 3, NO. 3, MARCH 1993

A DC Voltage is Equivalent to Two Traveling Waves on a Lossless, Nonuniform Transmission Line

Ching-Wen Hsue, Senior Member, IEEE

Abstract - A static dc voltage can be treated as two traveling waves propagating in opposite directions of a lossless, nonuni-form transmission line. The amplitudes of these two traveling waves are a function of the characteristic impedance of signal line. The concept of two traveling waves is applied to a time--domain-scatterIng-parameters analysis in a lossless, nonuniform transmission line terminated with nonlinear loads.


I. INTRODUCTON


W HEN A LOSSLESS transmission line is connected to a dc voltage source at one end and an appropriate resistive load at the other end,.a steady state dc voltage will finally be reached in the lossless signal line. Such a dc voltage is often treated as a static signal. In this paper, we treat such a static dc signal as two traveling waves propagating in opposite directions of the lossless signal line. In general, these two traveling waves have different signal amplitudes; the summation of these two traveling waves is equal to the static dc voltage. Such an approach will give us physical insights regarding the interaction between the transmission line and associated terminations in time domain analysis [1]-[4J.
II. TRAVELING WAVE SOLUONS
The time-space domain solutions of a lossless, uniforRl transmission line are [1]
V(t,x) = V+(t - ~) + V_ (t + ~), (I a)
l(t,x) = ~[V+(t-;)-V_(t+~)], (lb)
where V represents voltage, I is the current. Z = (/C)1/2 is the characteristic impedance. u = (LC)-1/2 is t1}e wave velocity, Land C are inductance and capacitance of the signal line per unit length. t is the time and x is the space variable. Note that V+(t - x/u) and V_ (t + x/u) represent the waves traveling in the +x (forward) and -x (backward) directions. respectively.
We assume that a uniform transmission line having a characteristic impedance Z is loaded with a dc voltage Vs, source resistance Rs at the left-hand side and a dc voltage V L, resistor load RL at the right-hand side. For such a
Manuscript received November 17, 1992.
The author is with AT&T Bell Laboratories. P.O. Box 900. Princeton. NJ 08540.
IEEE Log Number 9207600.
Footnote; 'The terminology "dc voltge" here and in the title might indicate not a continuous de voltage but a long-period pulse.

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to the circuit configuration at the load (right) end. For the circuit previously stated, the traveling wave Vx+(t, I) makes a contribution to the total incident and reflected waves a,(t) .. h(t) at the load (Ieft) end and the existence of Vx+(t, I) extends over the time interval II < I < T + I . Notice that the summation of existing time of traveling waves Vr+._ at both ends of the line is 2T.


IV. CONCLUSION


We decomposed a dc voltage on a lossless. nonuniform transmission line into two traveling waves propagating in opposite directions of the signal line. The amplitudes of two traveling waves are symmetric with respect to a horizontal line represenling half of the steady state voltage. This approach provides us physical insights regarding the interaction between transmission lines and associated loads in time-domain considerations.

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