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June 2012
Bandwidth Limit
On some types of heads a bandwidth limit function is available which is useful
for filtering high frequency noise and interference when trying to look at a
small steady or slowly-moving signal. This usually limits the risetime to 100ms
and the bandwidth to approximately 5Hz.
It is only available in waveform mode. It can be set on or off by pressing the
menu button and selecting Bandwidth Limit. This option does not appear
unless the feature is available with the connected head.
Trigger setting
Trigger Level
If the detector is seeing a signal which repeats in a regular fashion, for
example, a train of pulses, it is usual to set a trigger point so that each time
the instrument redraws the waveform it starts at the same place and a stable
display is achieved. For all but the very slow timebases it will be necessary to
set the vertical trigger level correctly to produce a stable display.
When the instrument is not triggered, ‘No trig’ is shown at the top of the
display, and any pulses will be seen to jump around on the screen. Once the
trigger has been correctly set and the instrument has ‘locked on’ to the
waveform, ‘Trig’ is shown and the pulse will be repeatedly drawn in the same
position resulting in a stable display.
Horizontal trigger adjustment is also provided so that the display can be
moved to the left or right. The meter is able to display information that
occurred before the trigger point as well as after.
