Tektronix 5441 Instruction Manual page 31

Operating Information-5441lR5441
EXAMPLE: Assume a peak-to-peak vertical deflection of
4.6 div and a VoltsIDiv switch setting of 5 V.
Peak-to-peak
-
4.6 5 (VoltsIDiv
-
=
23V
volts (div) setting)
NOTE
If an attenuator probe is used that cannot change the
scale factor readout (Volts/Div), multiply the right side
of the previous equation by the attenuation factor.
lnstantaneous Voltage Measurement-DC
To measure the dc level at a given point on the waveform
use the following procedure.
1. Set the input coupling of the vertical plug-in unit to
Gnd and position the trace to the bottom line of the graticule
(or other selected reference line). If the voltage to be mea-
sured is negative with respect to ground, position the trace
to the top line of the graticule. Do not move the vertical
Positon control after this reference has been established.
NOTE
To mesure a voltage level with respect to a voltage
other than ground, make the following changes to
step 1: Set the input coupling switch to dc and apply
the reference voltage to the input connector, then po-
sition the trace to the reference line.
2. Connect the signal to the input connector. Set the
input coupling to dc (the ground reference can be checked
at any time by setting the input coupling to Gnd).
3. Set the VoltsIDiv switch to display about 5 or 6 verti-
cal divisions of the waveform. Check that the variable
VoltsIDiv control (red knob) is in the Cal position. Adjust the
time-base triggering controls for a stable display.
4. Measure the distance in divisions between the refer-
ence line and the point on the waveform at which the dc
level is to be measured. For example, in Fig. 2-7 the mea-
surement is made between the reference line and point A.
5. Establish the polarity. The voltage is positive if the
signal is applied to the
+
input connector and the waveform
is above the reference line.
>
---f
----
Vertical
distance
I
--------
Reference line
I
Fig. 2-7. Measuring instantaneous DC voltage with respect to a
reference voltage.
6. Multiply the distance measured in step 4 by the
VoltsIDiv switch setting. Include the attenuation factor of
the probe, if applicable (see the note following the Peak-to-
Peak Voltage Measurement example).
EXAMPLE: Assume that the vertical distance measured
in 4.6 div, the polarity is positive, and the VoltsIDiv switch
setting is 2 V.
Instantaneous
-
4.6
-
2
(div) (VoItslDiv)
=
+
9.2 V
voltage
Comparison Measurements
In some applications, it may be necessary to establish a
set of deflection factors other than those indicated by the
VoltsIDiv or SecIDiv switches. This is useful for comparing
signals to a reference voltage amplitude or period. To estab-
lish a new set of deflection factors based upon a specific
reference amplitude or period, proceed as follows.
Vertical Deflection Factor
1. Apply a reference signal of known amplitude to the
vertical input connector. Using the VoltsIDiv switch and vari-
able VoltsIDiv control, adjust the display for an exact num-
ber of divisons. Do not move the variable VoltsIDiv control
after obtaining the desired deflection.
2. Divide the amplitude of the reference signal (volts) by
the product of the deflection in divisions (established in step
1) and the VoltsIDiv switch setting. This is the Deflection
Conversion Factor.
REV MAY 1982