DN062-13v01
JYE Tech - 1 - www.jyetech.com
Fig. 1
Fig. 2
How to Use External Trigger
Appliable model: 062
1. Brief explaination of external trigger
Trigger is an important portion of a oscilloscope. It is used to synchrounize captures to generate stable waveform
displays and help to capture rarely appear signals. Most oscilloscopes contain a trigger that uses internal signal, i.e.
the signal being viewed, as trig source. Some oscilloscopes can use signal other than the one being viewed as trig
source, too. This is called external trigger.
For 062 digital storage oscilloscopes with firmware version of -080 or later the external trigger was implemented.
This design note explains how to use the external trigger. It includes connection of external trig signal, selection of
trig sources, and adjustment of trigger level.
2. Connection of external trigging signal
The point for external trig signal input is Pin 12 of J5. There are two ways to connect external trig signal.
1) Connect to pin 12 of J5 directly
through a 2K – 10K (1/4W)
resister. (see Fig. 1). The resistor
protects scope from being
damaged and can not be omitted.
2) Connect to the 500Hz Test
Signal output terminal. In order
to be able to do so pin 4 of J5
must be shorted to pin 12 of J5
(Fig. 2). When pin 4 and pin 12
of J5 are shorted the 500Hz test
signal output will be
automatically disabled as long as
external trig source is selected.
3. Selection of trig sources
After external trig signal is connected you
have to tell the scope to use it as trig source.
This is done by first pressing [LEVEL] to
highlight the trigger level indicator. Then
press [LEVEL] again to toggle trig source to
external. The little case letter above trigger
level indicator shows currently selected trig
source. “ i ” stands for internal trig. “ e “ for
external trig. Press [LEVEL] to make letter
“ e “ is displayed.
4. Adjustment of trigger level
Trigger level is a constant voltage that
determines at what level trigs are generated.
Since trigs are only generated when signal
level intersects with trigger level this
voltage need to be adjusted from time to
time. For 062 oscilloscope trigger level is
adjusted by pressing [ + ] and [ - ] buttons
while the trigger level indicator is
highlighted.
When external trig source is selected trigger
level adjustable range is 0V – 5V. The small triangle on the right border of the waveform window indicates trigger
level with its bottom position for 0V and top position for 5V. Please note t\hat external trigger level is independent
of internal trigger level and is not related to any shown waveforms. It is only a genearted voltage used to compare
with unshown external trig signal to produce triggings.
From the discussion above we know that in order to be able to generate trigging by an external signal the external
To Next Page
Need help?
General
