Gated Mode
General
In Gated mode the generator outputs the waveform whenever the gating signal is high. The
generator is not synchronised with the gate source and the start and stop phase of the generator
waveform is therefore unpredictable. Except for the ability to turn the output signal on and off,
Gated mode is identical to Continuous mode. The same frequency setting is used in the two
modes. This permits the signal to be set up and applied before enabling the Gate.
Gated mode is turned on by pressing the
gated
soft-key on the
MODE
screen, called by the
MODE
soft-key on the main menu.
MODE more…
◊
◊
continuous
♦
gated setup…
◊
◊
sweep setup…
◊
The selection of the gate source signal is made by pressing the
setup
...
soft-key opposite
gated
on the
MODE
screen:
TRIG/GATE SETUP
source: manual
◊
int period: 90.8ms
Gate Source
Successive presses of the
source:
soft-key on the
TRIG/GATE SETUP
screen step the
source through the three possible options of
manual, external
and
internal
.
With
manual
selected the generator output is turned on and off by successive presses of the
front panel MAN TRIG key or by the
∗
TRG command from a remote interface.
With
external
selected the generator output runs when the signal at the TRIG/GATE IN
socket is high; this input has a TTL level (1.5V) threshold. The minimum pulse width that can be
used in this mode is 100ns and the maximum repetition rate is 100kHz. The maximum signal
level that can be applied without damage is ±10V.
With
internal
selected the generator is gated by an internal gate source whose period is set
by selecting
int period
on the same
TRIG/GATE SETUP
screen.
TRIG/GATE SETUP
◊
source:internal
♦
int period: 12.2ms
The period can be set from 0.2ms to 999s by direct keyboard entries in ms or seconds. Turning
the rotary control will increment or decrement the numeric value in steps determined by the
position of the edit cursor (flashing underline); the cursor is moved with the left and right arrowed
cursor keys. The internal source is a square wave; the duration of the gate is therefore 0.1ms to
499.5s in step with the source period of 0.2ms to 999s.
AUX OUT in Gate Mode
When Gated mode is selected the AUX OUT source automatically defaults to
trigger
;
trigger is a replica of the actual gate signal , i.e. the signal at the TRIG/GATE IN socket, the
internal gate source or the high/low condition ‘toggled’ by alternate presses of the MAN TRIG key
or the
∗
TRG remote command.
25
