Display; Setting Of Parameters; Defi Ning An Arbitrary Function - Hameg HMF2525 Handbuch

turning the knob CW resp. CCW. The parameter selected can
the set after pushing the knob. The value set will be accepted
by pushing the knob again.
Examples of setting parameters:
The following examples demonstrate the setting of parameters
for the square wave function. First push the square wave key
below the keyboard. You will see the following display:
Fig. 4.3: Front view including display of the settings
In this case the signal frequency was set to 50.0000000 kHz.
The simplest method of entering parameters quickly and ex-
actly is the entry via the numerical keyboard
parameters via the keyboard the value will be accepted upon
pushing the respective unit key MHz, kHz, Hz or mHz. Prior to
pushing any such key an entry may be deleted by pushing the
key (C/ESC). If an illegal value was entered, this will be in-
dicated by a warning tone (provided this had been activated), a
red error fi eld will be shown in the display, the instrument will
return to the former parameter unit.
In order to clarify this, enter a frequency of 20.56 kHz. Setting
the frequency is possible if the respective key of the softkey
menu lights up blue. Push the keys
proper sequence. The value entered will be accepted by pushing
the key to the side of the numerical keyboard. The following
display will be shown:
Fig. 4.4: Front view including display of the settings changed
Alternative methods of parameter entry are with the knob
and the arrow keys 9 .
Now push the second soft key (its blue LED will light up if it is
active) in order to set the amplitude. Use the left cursor key to
select the fi rst decimal position of the numerical value. Use the
knob to set 2.000 V. The display will show:
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Fig. 4.5: Front view including display of the amplitude change
O p e r a t i o n o f t h e H M F 2 5 2 5 / H M F 2 5 5 0
4
. When entering
, , , and in
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The entries of Sweep, Offset etc. are performed following the
same procedure.
If the signal output of the function generator is connected e.g. to
an oscilloscope, the signal may be shown on the display of the
oscilloscope. The key is active if its white LED is lighted.

4.5 Display

Depending on the type of function selected, the HMF2550 /
HMF2525 will display a preview of the waveform of the signal.
When the signal parameters are changed, the preview will be
adapted accordingly. This allows to see immediately how the
signal reacts to the entries. Above this display the setting of the
impedance (50Ω or open circuit), the selection of the external or
internal clock, and the selected interface will be shown.
The right portion of the display shows the variable parameters
in the soft key menu. This menu will be adapted to the waveform
selected. The setting of the parameters will be explained in the
following section „Setting of parameters". Most of the soft keys
are dual function: the active function will be shown in blue and
the inactive one in grey letters. Pushing the key will alternate
between functions.
The frequency display is a 9 digit one with a maximum resolu-
tion of 10μHz. The peak-to-peak values of amplitude, High/Low
level, and offset are displayed with a maximum of 5 digits and
a maximum resolution of 1mV.
Please note that the maximum output amplitude
which can be set will depend upon the impedance
selected (50 Ω or open circuit), it will be 10 V maxi-
mum with 50 Ω and 20 V maximum open circuit.
STOP

4.6 Setting of parameters

The soft keys allow to use the menu fi eld displayed. E.g. for the
waveform sine the parameters frequency, amplitude, and offset
can be varied. The amplitude may be also defi ned by setting the
upper (High level) and lower (Low level) levels. The selection
can be performed via the numerical keyboard, with the knob
or the arrow keys 9 . In addition to the parameters frequency,
amplitude, and offset also the duty cycle and the pulse width
(High/Low width) of square waves and pulses can be defi ned.
If the output was activated (the LED of the OUTPUT key lights
up white), any parameter changes will be immediately available
at the output of the function generator. The waveforms triangle
and pulse allow to defi ne the rise and fall times (Edging time).
With the waveform triangle also the symmetry (percentage of
the rise time to the period) may be adjusted.
If a selection menu offers several pages (e.g. with the waveform
pulse), the lowest soft key will light up green, this will be indicated
in the display as page 1/2. Pushing the green key will advance to
the second page, pushing it again will return to the fi rst page.
4.7 Defi ning an arbitrary function
In addition to the predefi ned waveforms the HMF2525 / HMF2550
allows to generate user-defi ned waveforms. However, there
are some rules and specifi cation limits to be observed which
will be described.
The arbitrary signals are digitally generated and can hence be
defi ned with great accuracy. The frequency and amplitude of
the waveform thus generated can be varied.
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Subject to change without notice