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TRIGGERING
The input signal must be properly triggered for stable
waveform observation. TRIGGERING is possible using the
input signal INTernally to create a trigger or with an EXTer-
nally provided signal of timing relationship to the observed
signal, applying such a signal to the E X T TRIG jack.
The SOURCE switch selects the input signal that is to be
used to trigger the sweep, with INT sync possibilities
(V.MODE, C H 1 , C H 2 , LINE) and E X T sync possibility.
*
Internal Sync
When the
SOURCE selection is in INT (V.MODE, C H 1 ,
C H 2 , LINE), the input signal is connected to the internal
trigger circuit. In this position, a part of the input signal fed
to the INPUT (5) or (9) jack is applied from the vertical
amplifier to the trigger circuit to cause the trigger signal
triggered with the input signal to drive the sweep.
When the V.MODE position is selected, the trigger source
is dependent upon the vertical MODE selection.
When the vertical MODE switch is selected in ALT,the trig-
ger source alternates between channel 1 and channel 2
with each sweep.
When the vertical MODE switch is selected in ALT the trig-
ger source alternates channel 1 and channel 2 with each
sweep.
This is convenient for checking amplitudes, waveshape, or
waveform
period
measurements
simultaneous observation of two waveforms which are not
related in frequency or period. However, this setting is not
suitable for phase or timing comparison measurements. For
such measurements, two traces must be triggered by the
same sync signal.
When the SOURCE selection is in C H 1 , the input signal at
the channel 1 INPUT (5) jack becomes trigger regardless of
the position of vertical MODE. When the SOURCE selection
is in C H 2 , the input signal at the channel 2 INPUT (9) jack
becomes trigger regardless of the position of
MODE. If the SOURCE switch is set to the LINE position,
triggering is derived from the input line voltage.
This is useful measurements that are related to line fre-
quency.
*
External Sync
When the SOURCE selection is in E X T , the input signal at
the E X T TRIG
@- jack becomes the trigger. This signal
must have a time or frequency relationship to the signal be-
ing observed to synchronize the display. External sync is
prefered for waveform observation in many applications.
For example, Fig. 6 shows that the sweep circuit is driven
by the gate signal when the gate signal in the burst signal is
applied to the E X T TRIG jack. Fig. 6 also shows the in-
put/output signals, where the burst signal generated from
the signal is applied to the instrument under test. Thus, ac-
curate triggering can be achieved without regard to the in-
14
and
even
permits
vertical
put signal fed to the INPUT (§) or (§) jack so that no further
triggering is required even when the input signal is varied.
Fig. 6
*
Coupling
The COUPLING switch selects the coupling mode of the
trigger signal to the trigger circuit according to the type of
trigger signal (dc, ac, signal superimposed on dc, signal
with high frequency noise.).
A C :
Most commonly
used position; permits triggering from
20 Hz to over 100 MHz. Blocks dc component of sync
trigger signal.
LFRE^:
Attenuate low-frequency component of sync trigger signal.
Useful to reduce low-frequency interference.
Waveform with low frequency noise.
Trigger signal by LF rejection
7
Fig.
HFjur,:
Attenuates
high-frequency
signal. Useful to reduce high-frequency noise, and permits
triggering from the modulation envelope of an amplitude
modulated rf signal.
DC:
Permits triggering from dc to over 100 MHz. Couples dc
component of sync trigger signal. Useful for triggering from
very
low
frequency
signals (below
waveforms with slow repeating dc.
Trigger signal
(Gate signal)
CH1 (Input signal to
' amplifier, etc.)
CH2 (Output signal
from amplifier, etc.)
component
of sync trigger
20 Hz)
or
ramp
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