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b)
N O R M A L
The normal s w e e p mode allows the trigger point
to be set with the L E V E L and S L O P E , like the A U T O
s w e e p mode. It is used to observe input signals of
frequency lower than 5 0 Hz as well as signals with
low repetition frequency.
N O T E : If no trigger signal is supplied or the trigger
point e x c e e d s the trigger range in the nor-
mal s w e e p mode, s w e e p operation discon-
tinues and no trace line is displayed.
c)
S I N G L E
The single mode is used for photography of non-
cyclic w a v e f o r m by sweeping it once.
Select A U T O or NORM of the TRIG MODE switches
© , input a signal with approx. the same amplitude
and frequency as the signal to be displayed as the
trigger signal, and set the trigger level.
Press the S I N G L E of the T R I G MODE s w i t c h e s (§).
Once S I N G L E is selected, the readout values and
scale illumination disappear. Pressing the SINGLE
turns on the R E A D Y L E D , which indicates the in-
strument is ready for the trigger signal. This LED
goes out on completion of A s w e e p . After confirm-
ing the above, apply the signal to be observed and
press the S I N G L E to make the instument ready for
the trigger signal. S w e e p operation is executed
once w h e n the trigger signal is applied, and then
the R E A D Y LED goes out. At this time, the readout
values are displayed and the scale illumination
lights up instantaneously.
N O T E : If several channels are selected with the
V E R T I C A L MODE switches @ , they cannot
be observed in the A L T mode. Set the
C H O P / A L T switch to CHOP in such a case.
(2)
SOURCE
Trigger signal to be used is selected with the A S O U R C E
s w i t c h e s © . If the A S O U R C E s w i t c h is set to V E R T ,
triggering is made by a signal of a lower channel num-
ber selected with the V E R T I C A L MODE s w i t c h e s @ .
If any of CH1 to C H 4 of the A S O U R C E is selected, trig-
gering is made by the signal of the selected channel,
regardless of setting of the V E R T I C A L MODE switches
©•
If the A S O U R C E s w i t c h is set to LINE, triggering is
made by the commercial frequency.
(3) COUPLE Switch
The A COUPLING s w i t c h e s (38) is used to select coupling
methods of the trigger signal.
a)
A C
Selects A C (capacitive) coupling. DC component
in the trigger signal is eliminated, and triggering is
done by A C signals. T h i s coupling is conveniently
used for ordinary measurement since it provides
stable triggering independent of DC component.
However, if frequency of the trigger signal is low-
er than 2 0 Hz, trigger signal level is reduced, caus-
ing difficulty in triggering.
b)
N O I S E R E J
Trigger signal w i t h reduced trigger sensitivity is
supplied to the trigger circuit. For trigger signals
20
with noises, this mode provides stable triggering,
c)
H F R E J
Trigger signal is supplied to the trigger circuit via
a low- pass filter to cut off high-frequency compo-
nents (higher than 3 0 kHz). T h u s , triggering is done
by low-frequency components only. This mode pro-
vides stable triggering for trigger signals with over-
lapped high-frequency noises as s h o w n in Fig. 9.
W a v e f o r m
w i t h o v e r l a p p e d h i g h - f r e q u e n c y n o i s e s
T r i g g e r s i g n a l in H F R E J
Fig. 9
d)
DC
Trigger signal and trigger circuit are coupled direct-
ly, enabling triggering from direct current. This
mode is suitable for triggering of low-frequency sig-
nals lower than 2 0 Hz or ramp waveform with slow
repetition or change like the direct current.
e)
T V F R A M E , T V LINE
To observe the video signals, setting the A
COUPLING © to T V F R A M E causes the vertical
synchronizing signal to trigger, and setting to T V
LINE causes the horizontal synchronizing signal to
trigger. T h e s e triggering operations are stable,
regardless of setting of the A L E V E L (39). If polarity
of the synchronizing pulses is negative, set the A
S L O P E ® to negative ( - ) . If it is positive, set the
A S L O P E © to positive ( + ).
If A INT B, A L T , or B of the H O R I Z O N T A L MODE
s w i t c h e s © is selected, the B COUPLING © is au-
tomatically set to T V LINE.
Besides, the B S L O P E is set to the same state as
the A S L O P E .
Set the S L O P E as follows:
Fig.
m o d e
S L O P E
+
S L O P E
1 0
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