Operating Instructions—434
3. Set both In pu t Coupling switches to DC (AC if DC
component of inp ut signal is too large).
4. Set the Vertical Mode switch to A L T . Set the
V O LT S /D IV switches so the signals are about equal in
am plitude.
5. Set the TR IG G ER SOURCE switch to COMP.
6. Set the Vertical Mode switch to A D D . Set the
IN VE R T switch so the common-mode signals are of
opposite polarity.
7. Adjust the Channel 2 V O LT S /D IV switch and
Variable VO LT S /D IV control fo r m axim um cancellation of
the common-m ode signal.
8. The signal which remains should be only the desired
portion of the Channel 1 signal. The undesired signal is
cancelled out.
EXAM PLE. An example of this mode of operation is
shown in Fig. 2-14. The signal applied to Channel 1 con
tains unwanted line-frequency components (Fig. 2-14A). A
corresponding line-frequency signal is connected to Channel
2 (Fig. 2-14B). Fig. 2-14C shows the desired portion of the
signal as displayed when comm on-mode rejection is used.
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Line
freque nc
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X
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x —
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(A ) C hannel 1 signal. (B> C hannel 2 signal. (C) R e sultant d ispla y.
Fig. 2-14. Using the A L G A D D fea tu re fo r com m o n-m ode re jectio n. (A ) Channel 1 signal co n tains desired in fo rm a tio n along w ith line-
frequ e n cy com ponent. (B) Channel 2 signal con tains line-fre que n cy o n ly , (C) re su ltant C R T d isp lay using c om m o n-m o de re jectio n.
2-23
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