Triggered Burst and Gate
General
Triggered Burst and Gated modes are selected from the
MODE
screen, called by the MODE key,
as alternatives to the default continuous mode.
MODE:
♦
continuous
◊
gated
◊
triggered setup…
◊
In Triggered Burst mode a defined number of cycles are generated following each trigger event.
This mode is edge triggered.
In gated mode the generator runs whenever the gating signal is true. This mode is level sensitive.
Both Triggered Burst and Gated modes can be controlled by either the internal trigger generator,
an external trigger input, by the front panel MAN/SYNC key or by remote control.
Internal Trigger Generator
The period of the internal trigger generator is set with the
period
soft-key on the
TRIGGER
INPUT SETUP
screen called by the TRIG IN key.
TRIGGER INPUT SETUP:
◊
source: internal
◊
slope: positive
♦
period: 2·00ms
The internal trigger generator divides down a crystal oscillator to produce a 1:1 square-wave with
a period from 0·02ms (50kHz) to 200s (·005Hz). Generator period entries that cannot be exactly
set are accepted and rounded up to the nearest available value, e.g. ·109ms is rounded to ·12ms.
When Triggered Burst or Gated modes are selected the SYNC OUT source automatically defaults
to
trigger
which is the output of the internal trigger generator when internal triggering or
gating is specified.
In Triggered Burst mode the selected edge of each cycle of the trigger generator is used to
initiate a burst; the interval between bursts is therefore 0·02ms to 200s as set by the generator
period.
In Gated mode the output of the main generator is gated on whilst the trigger generator output is
true; the duration of the gate is therefore ·01ms to 100s in step with trigger generator periods of
·02ms to 200s.
External Trigger Input
External trigger or gate signals are applied to the front panel TRIG IN socket which has a TTL
level (1·5V) threshold. In Triggered Burst mode the input is edge sensitive; the selected edge of
each external trigger initiates the specified burst. In Gated mode the input is level sensitive; the
output of the main generator is on whilst the gate signal is true.
The minimum pulse width that can be used with TRIG IN in Triggered Burst and Gated mode is
50ns and the maximum repetition rate is 1MHz. The maximum signal level that can be applied
without damage is ±10V.
When Triggered Burst or Gated modes are selected the SYNC OUT source automatically defaults
to
trigger
which is always a positive-edged version of the external trigger or gate signal when
external triggering or gating is specified.
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