Trigger Input - Hameg HMF2525 Manual

C o n t r o l o f t h e s i g n a l o u t p u t
6 Control of the signal output
The key OUTPUT is used to
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turn the output on or off at any
time. Prior to turning the output
on, all parameters can be set
comfortably. If the output is ac-
tivated, the white LED of the key
will light up.
A positive or negative DC offset may be added to the output
sig-nal. If an offset was selected it will be added by pushing the
key OFFSET which will light up.
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Fig. 6.2: Explanation for offset function
The diagram shows two waveforms. The lower waveform
without offset is referenced to ground with an amplitude of
10 V . The limits of the output stage are shown from –10 V to
pp
+10 V which equals 20 V . The second upper waveform has an
pp
offset of +5 V, it reaches the upper limit of +10 V, hence it is not
possible to increase the offset further, e.g. to +6 V. The ampli-
tude will then be automatically decreased. The signal ampli-
tude can not be increased if the offset is already +5 V as this
would also violate the limit.
If the offset is decreased to +4 V, the amplitude can be
increased to 12 Vpp.
The output signal polarity can be inverted by pushing the key
which will light up white. This feature is available
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INVERT
in PULSE mode only.
Any offset will be also be affected by a signal inversion.
Inversion is only possible for the waveform pulse which is
not symmetrical to ground.
As mentioned the maximum output voltage including an offset
can not be increased beyond 20 V
amplitude of 8 V e.g. the maximum offset possible is 6 V. Within
pp
this range the offset voltage can be varied continuously from
negative to positive values. The same conditions are valid if the
sweep function is used with offset.
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Subject to change without notice
Fig. 6.1:
Controls for
output, offset
and invert
function
open circuit. Hence, for an
pp
7 Front panel connections
7.1 Signal Output
The signal output of the HMF2525 / HMF2550 has an impedance
of 50Ω and can be turned on or off with the key OUTPUT
output is short-circuit proof and protected against short-term
applied voltages of up to ±15 V (DC and AC peak).
7.2

Trigger Input

The HMF2525/2550 offers different operating modes. In addition
to the standard mode „free-running" (continuous), signals may
be generated triggered or gated. The selection is performed in
the BURST or SWEEP modes. After turn-on the instrument will
be in the free-running mode.
In gated mode the output signal will be gated by a TTL signal,
applied to the TRIG INPUT connector
operating mode is asynchronous. The phase of the output signal
can be any when gated because the signal will be continuously
generated. Normally, the output will be activated when the gate
signal is HIGH (TTL) , if it is LOW it will be off. Whether the si-
gnal starts at a rising or falling edge can be slected at the resp.
„system settings" menu. In external trigger mode the trigger
is also applied to the TRIG INPUT connector
signal may be also a command *TRG sent via the interface.
This operating mode is synchronous, i.e. the triggered signal
will start at its beginning i.e. at zero. One or several periods
will be generated depending on the number of cycles set on
the instument before.
In case the sweep function is activated, a trigger will generate
just one sweep, after completion the function generator will
wait for the next trigger. During the waiting period no signal
will be generated.
Fig. 7.2: Output signal controlled by a GATE signal
Fig. 7.1:
Outputs on the
front panel
. The
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on the front panel. This
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. A trigger
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