Tektronix 2335, Instruction Manual, Page: 53 / 104

(CH 1 + CH 2). If the CH 2 IN VE R T push button is pressed
in, the waveform displayed is the difference between the
signals applied to the Channel 1 and Channel 2 inputs
(CH 1 — CH 2). The total deflection factor in the ADD
mode is equal to the deflection factor indicated by either
VO LTS/DIV switch (when both VO LTS/DIV switches are
set to the same deflection factor). A common use fo r the
ADD mode is to provide a dc offset fo r a signal riding on
top o f a high dc level.
The following general precautions should be observed
when using the ADD mode.
a. Do not exceed the input voltage rating o f the oscillo­
scope.
b. Do not apply signals that exceed the equivalent o f
about eight times the V O LT S /D IV switch settings,
since large voltages may distort the display. For
example, w ith a VO LTS /D IV switch setting o f 0.5,
the voltage applied to th a t channel should not exceed
approximately 4 volts.
c. Use Channel 1 and Channel 2 POSITION control
settings which most nearly position the signal on each
channel to midscreen when viewed in either CH 1 or
CH 2 VE R TIC A L MODE. This ensures the greatest
dynamic range fo r ADD mode operation.
d. To attain similar response from each channel, set
both the Channel 1 and Channel 2 AC-GND-DC
switches to the same position.
EXAMPLE: Using the graticule center line as 0 V,
the Channel 1 signal is at a 3-division, positive dc level
(see Figure 14A).
1. M ultiply 3 divisions by the V O LT S /D IV switch
setting to determine the dc-ievef value.
2. To the Channel 2 input connector, apply a negative
dc level (or positive level, using the CH 2 IN V E R T switch)
whose value was determined in step 1 (see Figure 14B).
3. Select ADD VER TICAL MODE to place the resultant
display w ithin the operating range o f the vertical
POSITION controls (see Figure 14C).
40 2335 Operators
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