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P R O B E COMPENSATION
If accurate measurements are to be made, the effect of the
probe being used must be properly adjusted output of the
measurement system using the internal calibration signal or
some other square wave source.
1. Connect probe to INPUT jack. Connect ground clip of
probe of oscilloscope ground terminal and touch tip of
probe to C A L terminal.
2. Select single trace operation of channel 1 , then channel
2, for step 3 and 4.
Set the VOLTS/DIV to 20mV/div.
3 . Set the scope controls to display 3 or 4 cycles of C A L
square wave at 5 or 6 divisions amplitude.
4. Adjust compensation trimmer on probe for optimum
square wave waveshape (minimum overshoot, rounding
off, and tilt).
Fig. 11
TRACE ROTATION COMPENSATION
Rotation from a horizontal trace position can be the cause
of measurement errors.
Adjust the controls for a single display. Set the AC-GND-DC
switch to GND and trigger MODE to AUTO. Adjust the •
POSITION control such that the trace is over the center
horizontal graticule line. If the trace appears to be rotated
from horizontal, align it with the center graticule line using
the T R A C E ROTATION control located on the front panel.
DC VOLTAGE MEASUREMENTS
This procedure describes the measurement procedure for
waveforms including the dc component.
Procedure:
1. Connect the signal to be measured to the
jack.Set the vertical MODE to the channel to be used.
Set the VOLTS/DIV and SWEEP TIME/DIV switch to ob-
tain a normal display of the waveform to be measured.
Set the VARIABLE control to C A L position.
2. Set the trigger MODE switch to AUTO and AC-GND-DC
to the GND position, which established the zero volt
reference. Using the T POSITION control, adjust the
trace position to the desired reference level position,
making sure not to disturb this setting once made.
APPLICATIONS
3. Set the AC-GND-DC switch to the DC position to
observe the input waveform, including its dc compo-
nent. If an appropriate reference level or VOLTS/DIV
setting was not made, the waveform may not be visible
on the C R T screen at this point. If so, reset VOLTS/DIV
and/or the y POSITION control.
4. Use the
the waveform to be measured to the center vertical
graduation line of the C R T screen.
5. Measure the vertical distance from the reference level to
the point to be measured, (the reference level can be
rechecked by setting the AC-GND-DC switch again to
GND).
Multiply
VOLTS/DIV setting and the probe attenuation ratio as
well. If " x 5 G A I N " has been set, multiply the value by
1/5 as well. Voltages above and below the reference
level are positive and negative values respectively.
Correct
compensation
Using the formula:
DC level = Vertical distance in divisions x (VOLTS/DIV set-
ting) x(probe attenuation ratio) x " x 5 GAIN" value
Over
compensation
Insufficient
compensation
[EXAMPLE]
For the example, the point being measured is 3.8 divisions
from the reference level (ground potential).
If the VOLTS/DIV w a s set to 0.2 V and a 10:1 probe was
used. (See Fig. 12)
Substituting the given values:
INPUT
DC level = 3.8 (div) x 0.2(V) x 10 = 7.6 V
POSITION control to bring the portion of
the
distance
measured
Measuring point adjusted to the center
vertical scale by
POSITION
.Ground potential adjusted by
0 POSITION (reference line)
Fig. 12
above
by
the
_ l
(1/5)
17
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