Radar System Engineering

Sl?lc.10.91 LINE-TYPE PULSERS 373
During the rising part of the plate current curve, the pulse transformer
induces a negative voltage wave on the delay line equal to the
induced positive voltage on the grid. The pulse length is then fixed by
the time required for thk negative wave to travel down the line and back
to the grid. Upon arrival at the grid, the negative wave drives the tube
toward cutoff, a process helped again by the regenerative action of the
Practical Considerations. —The most economical pulser would have
power flowing only during the pulse. Of course, energy must flow back
to recharge those elements which store and deliver pulse power, but the
design should not include vacuum tubes that conduct during the time
between pulses, and are turned off during the pulse. Judicious use of
plate-coupled and cathode-coupled circuits usually will permit all tubes
to be biased to cutoff except during the pulse. Pulse transformers can
also be used for phase reversal, impedance-matching, and circuit isolation.
Means are now available for computing the important design
parameters of such pulse transformers. 1
Successful hard-tube pulsers have been made with power outputs up
1PuZseGenerators,Vol. 5, Chaps. 12 to 15, Radiation Laboratory Series.