Radar System Engineering

388 THE MAGNETRON AND THE PULSER [SEC.10.11
harmful only in those radars which detect moving targets (see Chap. 16)
by comparing successive pulse phases.
We have already remarked that pulser internal impedance may sometimes
play a deciding role in mode stability. It is also true that the power
supply steady-state V-I characteristic may influence magnetron behavior.
L ---
I
.— .—. .d
FIG. 10.48.—Medium-powerairbornepulser.
A mode change in which an ~ncrease in voltage calls for a decrease in current
can cause the instability typical of any negative-resistance load. 1
It is of considerable importance that the designer consider the problem of
stability from the standpoint of the system as a whole.
The necessity of providing for a varying pulser load influences
rectifier and power-supply design. It is frequently desirable to change
the repetition rate of the pulser. This change is easy in principle, but in
1RL Report No. S09, Sept. 28, 1945.