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Fig. 37
indicates high frequency boost in an
amplifier accompanied by a lightly damped " s h o c k "
transient.
The sinusoidal type of diminishing oscillation along
the top of the square w a v e indicates a transient os-
cillation in a relatively high " Q " network in the
amplifier circuit. In this case, the sudden transition
in the square w a v e potential from a sharply rising,
relatively high frequency voltage, to a level value of
low frequency voltage, supplies the energy for os-
cillation in the resonant network. If this network in
the amplifier is reasonably heavily damped, then a
single cycle transient oscillation may be produced
as indicated in F i g . 38.
Fig. 3 9 summarizes the preceding explanations
and serves a s a handy reference.
A . F r e q u e n c y d i s t o r t i o n , { a m p l i t u d e
r e d u c t i o n of l o w - f r e q u e n c y
c o m p o n e n t ) , no phase shift.
D. L o w - f r e q u e n c y phase shift
G . H i g h - f r e q u e n c y loss
and p h a s e shift.
Fig. 3 9 S u m m a r y of w a v e f o r m a n a l y s i s for square w a v e testing of amplifiers
Fig. 3 8 Effect of high-frequency boost and good
B. L o w - f r e q u e n c y b o o s t
( a c c e n t u a t e d f u n d a m e n t a l ) .
E .
L o w - f r e q u e n c y loss
and phase shift.
H. D a m p e d o s c i l l a t i o n .
damping
C .
H i g h - f r e q u e n c y loss — N o phase
s h i f t .
F .
H i g h - f r e q u e n c y loss and
l o w - f r e q u e n c y phase shift.
I.
L o w - f r e q u e n c y phase s h i f t (trace
t h i c k e n e d b y h u m - v o l t a g e ) .
27
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