Tektronix 5110, Instruction Manual

Page: 15 / 128

Operating lnstructions-5110
(Al
Fig. 1-4. Measuring instantaneous de voltage with respect to «
reference voltage.
2. Divide the amplitude of the reference signal (volts)
by the product of the deflection indivisions (established in
step 1) and the Volts/Div switch setting. This is the
Deflection Conversion Factor.
Deflection
Conversion
Factor
reference signal amplitude (volts)
deflection X Volts/Div
(divisions) setting
3. To determ i ne the peak-to-peak amplitude of a signal
compared to a reference, disconnect the reference and
apply the signal to the input connector.
4. Set the Volts/Div switch to a setting that provides
sufficient deflection to make the measurement. Do not
readjust the variable Volts/Div control.
5. Establish the polarity. The voltage is positive if the
signal is applied to the 4- input connector and the
waveform is above the reference line.
6. Multiply the distance measured in step 4 by the
Volts/Div switch setting. Include the attenuation factor of
the probe, if applicable (see the note following the Peak-
to-Peak Voltage Measurement example).
5. To establish a Modified Deflection Factor at any
setting of the Volts/Div switch, multiply the Volts/Div
switch setting by the Deflection Conversion Factor es­
tablished in step 2.
Modified
Deflection
Factor
Volts/Div
setting
Deflection
X Conversion
Factor
EXAMPLE: Assume that the vertical distance measured
is 4.6 divisions, the polarity is positive, and the Volts/Div
switch setting is 2 V.
instantaneous _ 4.6 x 2 _ +9.2
Voltage (divisions) A (Volts/Div) volts
Comparison Measurements
In some applications, it may be necessary to establish a
set of deflection factors other than those indicated by the
Volts/Div or Seconds /Div switches. This is useful for
comparing signals to a reference voltage amplitude or
period. To establish a new set of deflection factors based
on a specific reference amolitude or period, proceed as
follows:
Vertical Deflection Factor
1. Apply a reference signal of known amplitude to the
vertical input connector. Using the Volts/Div switch and
variable Volts/Div control, adjust the display for an exact
number of divisions. Do not move the variable Volts/Div
control after obtaining the desired deflection.
6. Measure the vertical deflection in divisions and
determine the amplitude by the following formula:
Signal
Amplitude
Modified
Deflection
Factor
Deflection
(divisions)
EXAMPLE: Assume a reference signal amplitude of 30
volts, a Volts/Div switch setting of 5 V and a deflection of
four divisions. Substituting these values in the Deflection
Conversion Factor formula (step 2):
30 V
(4) (5 V)
= 1.5
Then, with a Volts/Div switch setting of 2 V, the
Modified Deflection Factor (step 5) is:
(2 V) (1.5) = 3 volts/division
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