Tektronix 434, Instruction Manual

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O pe ra tin g In s tru c tio n s —4 3 4
3. Set b o th In p u t C o u p lin g sw itches to DC (A C if DC
c o m p o n e n t o f in p u t signal is to o large).
4. Set th e V e rtic a l Mode s w itch to A L T . Set the
V O L T S /D IV sw itches so th e signals are a b o u t equal in
a m p litu d e .
5. Set th e T R IG G E R S O U R C E s w itc h to COMP.
6. Set th e V e rtic a l M ode s w itch to A D D . Set the
IN V E R T s w itch so th e c o m m o n -m o d e signals are o f
o p p o site p o la rity .
7. A d ju s t th e Channel 2 V O L T S /D IV s w itch and
V a ria b le V O L T S /D IV c o n tro l fo r m a x im u m c a n ce lla tio n of
th e co m m o n -m o d e signal.
8. The signal w h ic h rem ains should be o n ly the desired
p o rtio n o f th e Channel 1 signal. The undesired signal is
cancelled o u t.
E X A M P L E . A n exam ple o f th is m ode o f o p e ra tio n is
show n in Fig. 2-14. T h e signal applied to C hannel 1 co n ­
ta in s u n w a nte d lin e -fre q u e n c y c o m p o n e n ts (F ig. 2 -1 4 A ). A
c o rre sp o nd in g lin e -fre q u e n c y signal is connected to Channel
2 (F ig. 2 -1 4 B ). Fig. 2-14C shows th e desired p o rtio n o f the
signal as displayed w hen c o m m o n -m o d e re je c tio n is used.
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(A ) C h a n n e l 1 s ig n a l. (B> C h a n n e l 2 s ig n a l. (C ) R e s u lta n t d is p la y .
F ig . 2 -1 4 . U sin g th e A L G A D D fe a tu re f o r c o m m o n - m o d e r e je c tio n . (A ) C h a n n e l 1 signal c o n ta in s d e s ire d in f o r m a t io n a lo n g w it h lin e -
fre q u e n c y c o m p o n e n t. (B ) C h a n n e l 2 signal c o n ta in s lin e - fre q u e n c y o n ly , (C ) re s u lta n t C R T d is p la y u s in g c o m m o n - m o d e re je c tio n .
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