Amplitude Comparison - Tektronix 2221 Operator's Manual

Basic Applications— 2221 Operators
Л
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O
100
CH 1 SIGNAL
WITH UNWANTED
FREQUENCY
COMPONENT
90
100
90
10
CH 2 SIGNAL
FROM UNWANTED
FREQUENCY
SOURCE
( INVERTED )
10
( A ) CH 1 AND CH 2 SIGNALS.
1 V
100
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2ms
HORIZONTAL
DISTANCE
90
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SIGNAL WITH
UNWANTED
FREQUENCY
COMPONENT
CANCELED
OUT
Figure 6-5. Time duration.
10
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( B) RESULTANT SIGNAL.
6. Measure the horizontal distance between the time
measurement points .
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Figure 6-4 . Common-mode rejection .
7. Calculate time duration, using the following formula :
Time
Duration
Horizontal
SEC /DIV
Distance ( Divisions ) Х Switch Setting
Magnification Factor
TIME DURATION
on
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To measure time between two points on a waveform ,
use the following procedure:
EXAMPLE: The
distance between the
time
measurement points is 8.3 divisions (see Figure 6-5) ,
and the SEC/ DIV switch is set to 2 ms . The X10
Magnifier switch is pushed in (X1 magnification ) .
1. Preset instrument controls and obtain a baseline
trace .
Substituting the given values :
Time Duration
8.3 div x 2 ms /div 16.6 ms
2. Apply the signal to either vertical -channel input con
nector and set the VERTICAL MODE switches to display
the channel used .
AMPLITUDE COMPARISON
3. Adjust the TRIGGER LEVEL control to obtain a
stable display.
4. Set the SEC /DIV control to display one complete
period of the waveform . Ensure that the SEC/ DIV Variable
control is in the CAL detent.
In some applications it may be necessary to establish a
set of deflection factors other than those indicated by the
VOLTS /DIV switch settings. This is useful for comparing
unknown signals to a reference signal of known amplitude .
To accomplish this , a reference signal of known amplitude
is first set to an exact number of vertical divisions by
adjusting the VOLTS /DIV switch and Variable control.
Unknown signals can then be quickly and accurately com
pared with the reference signal without disturbing the set
ting of the VOLTS /DIV Variable control. The procedure is
as follows:
5. Position the display to place the time- measurement
points on the center horizontal graticule line (see Figure
6-5 ).
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C
6-7