Control Of The Signal Output - Hameg HMF2525 Manual

5.4.5 System Settings
Here the load impedance (50Ω/ user defined, HIGH), the
amplitude unit and internal or external clock, can be selected.
In addition, the phase of two HMF, which are connected to
each other, can be synchonised with the soft key SYNCHRO.
The lowest softmenu button gave access to a menu where the
trigger settings can be made.
Please make sure, that the load impedance setting
is correct for the device under test! (If the load
impedance is set to 50Ω but the DUT has a high
impedance the amplitude on the output will be up
to twice as high as the value shown on the display
and may destroy the DUT!)
With the left arrow button you can jump back to the last menu.
Submenu TRIGGER
In this menu the trigger source (internal / external), the con-
nector TRIG OUTPUT (On/Off) as well as the associated edge
settings (rising / falling) can be defined.
The trigger source can be set to intern (immediately) or extern.
In the mode EXTERNAL 3 different trigger options exists. The
instrument selects / performs the appropriate function auto-
matically:
– by pressing the blue blinking REMOTE button a manual trig-
ger is initiating without an external signal source is needed,
– sending the Remote command TRIG via interface,
– depending on the chosen setting a positive / negative TTL
signal is generated on the front panel connectors TRIG
INPUT / OUTPUT.
Fig. 5.12: Successful self
alignment completed
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 signals. The lower curve without offset
is referenced to ground with an amplitude of 10 V
of the output stage are shown from –10 V to +10 V which equals
20 V . The second upper curve has an offset of +5 V, it reaches
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the upper limit of +10 V, hence it is not possible to increase the
offset further, e.g. to +6 V. The amplitude will then be automa-
tically decreased. The signal amplitude 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 V
The output signal polarity can be inverted by pushing the key
INVERT which will light up white. This feature is available
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in PULSE mode only.
Any offset will be also be affected by a signal inver-
sion. Inversion is only possible for the waveform
pulse which is the only one 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
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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.
Fig. 6.1:
Controls for
output, offset
and invert
function
. The limits
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.
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open circuit. Hence, for an
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Subject to change without notice
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