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REF cursor
Fig. 3 5
1 2 .
RELATIVE MEASUREMENTS
If the frequency and amplitude of some reference signal are
known, an unknown signal may be measured for level and
frequency
without use of the V O L T S / D I V or
TIME/DIV for calibration.
The measurement is made in units relative to the reference
signal.
• Vertical Sensitivity
Setting the relative vertical sensitivity using a reference
signal.
Procedure:
1 . Apply the reference signal to the INPUT jack and adjust
the display for a normal waveform display.
Adjust the V O L T S / D I V and V A R I A B L E so that the signal
coincides with the C R T f a c e ' s graduation lines. After
adjusting, be sure not to disturb the setting of the
V A R I A B L E control.
2. The vertical calibration coefficient is now the reference
signal's amplitude (in volts) divided by the product of
the vertical amplitude set in step 1 and the V O L T S / D I V
setting.
Using the formula:
Vertical coefficient
_
Voltage of the reference signal (V)
Vertical amplitude (div) x V O L T S / D I V setting
3 . Remove the reference signal and apply the unknown
signal to the INPUT jack, using the V O L T S / D I V control
to adjust the display for easy observation. Measure the
amplitude
of the displayed waveform
following relationship to calculate the actual amplitude
of the unknown waveform.
Using the formula:
Amplitude of the unknown signal (V)
= Vertical distance (div) x Vertical coefficient
x V O L T S / D I V setting
Measured value
cursor
S W E E P
[EXAMPLE]
For the example, the V O L T S / D I V is 1 V/div.
The reference signal is 2 V r m s . Using the V A R I A B L E , ad-
just so that the amplitude of the reference signal is 4 divi-
sions. (See Fig. 3 6 )
Substituting the given value:
= 0 . 5
Then measure the unknown signal and V O L T S / D I V is
5 (V/div) and vertical amplitude is 3 divisions.
Substituting the given value:
Effective value of unknown signal = 3 (div) x 0 . 5 x 5(V/div)
•
Setting the relative sweep coefficient with respect to a
reference frequency signal.
and use the
Procedure:
1. Apply the reference signal to the INPUT jack, using the
Reference signal
Adjusted reference signal
Unknown signal
Fig. 36
w
• .
•
2 (Vrms)
Vertical coefficient =
4 (div) x 1 (V/div)
Period
V O L T S / D I V and V A R I A B L E to obtain an easily observed
waveform display.
Using the S W E E P TIME/DIV and V A R I A B L E adjust one
cycle of the reference signal to occupy a fixed number
of scale divisions accurately. After this is done be sure
not to disturb the setting of the V A R I A B L E control.
= 7 . 5 V rms
27
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