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P h a s e d i f f e r e n c e
O n e
c y c l e a d j u s t e d t o o c c u p y 8 d i v
E x p a n d e d s w e e p w a v e f o r m d i s p l a y
Fig. 25
R E L A T I V E MEASUREMENTS
If the frequency and amplitude of some reference signal
are known, an unknown signal may be measured for voltage
and frequency without use of the V O L T S / D I V or S W E E P
T I M E / D I V controls.
The measurement is made in units relative to the reference
signal.
* Vertical Sensitivity
Setting the relative vertical sensitivity using a reference
signal:
1. Apply the reference signal to I N P U T 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 controls so
that the signal amplitude coincides with a few divisions
of graticule. After adjusting, do not to disturb the set-
ting of the V A R I A B L E control.
2 . Divide the voltage amplitude of the reference signal by
the product of the vertical amplitude and V O L T S / D I V
settings given in step 1 above.
Vertical coefficient
Voltage of reference signal ( V )
Vertical amplitude (div) x V O L T S / D I V setting
P h a s e d i f f e r e n c e
3. Remove the reference signal and apply the
signal to I N P U T jack. Set the V O L T S / D I V control to
for eacy observation. Measure the amplitude of the dis-
played waveform, and use the following relationship
to calculate the voltage of the unknown waveform.
Amplitude of unknown signal ( V )
= Vertical distance (div) x Vertical coefficient
x V O L T S / D I V setting
R e f e r e n c e s i g n a l
A d j u s t e d r e f e r e n c e s i g n a l
U n k n o w n s i g n a l
Fig. 26
[ E X A M P L E ]
For the example shown in F i g . 2 6 , the V O L T S / D I V setting
is 1 V . T h e reference signal is 2 V r m s . Using the V A R I -
A B L E control, adjust so that the amplitude of the reference
signal is 4 div. Then we have
W
-
,
. .
2 V r m s
X J C
Vertical coefficient = . , , . . — r ~ 7 7 7 7
4 (div) x 1 ( V )
T h e n , measure the unknown signal. Suppose that V O L T S /
D I V
setting is 5 V and vertical amplitude is 3 div, then we
have
Effective value of the unknown signal = 3 ( d i v ) x 0 . 5 x 5 ( V )
unknown
=
0.5
= 7.5 V r m s
29
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