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a leading direction. F i g . 3 5 indicates a 1 0 ° phase
shift in a low frequency component in a lagging
direction. The tilts are opposite in the two cases
because of the difference in polarity of the phase
angle in the two cases a s can be checked through
algebraic addition of components.
Fig. 3 6 indicates low-frequency components which
have been reduced in amplitude and shifted in
phase.
It will be noted that these examples of
low-frequency
distortion are characterize by
change in shape of the flat top portion of the square
wave.
F i g .
3 1 B
previously
high-frequency
overshoot
amplifier response at the higher frequencies. It
should again be noted that this overshoot makes
itself evident at the top of the leading edge of the
square wave. This characteristic relationship is ex-
plained
by
remembering
well-shaped square w a v e , the sharp rise of the
leading edge is created by the summation of a
F X 3 O U T O F P H A S E
( L E A D )
Fig. 3 3 S q u a r e w a v e tilt resulting from 3rd
harmonic phase shift
F X !
F X 1 O U T O F P H A S E
( L E A D )
Fig. 3 4 Tilt resulting from phase shift of
fundamental frequency in a leading
direction
26
d i s c u s s e d ,
revealed a
produced
by
rising
that
in
a
normal
practically
infinite
number
ponents. If an abnormal rise in amplifier response
occurs at gigh frequencies, the high frequency
components in the square w a v e will be amplified
disproprotionately greater than other components
creating a higher algebraic sum along the leading
edge.
F X
I-
F X 1 O U T O F P H A S E
( L A G )
Fig. 3 5 Tilt resulting from a phase shift of
fundamental frequency in a lagging
direction
Fig. 3 6 L o w frequency component loss and
phase shift
Fig. 3 7 Effect of high-frequency boost and poor
damping
of
harmonic
com-
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