56
Subject to change without notice
Reference points
Those points in amplitude and time which the user entered are
called reference points. A waveform will be the more similar to
the desired one the more reference points were entered. Ho-
wever, it is not necessary to enter very many as the processor
will automatically interpolate if that should be acceptable. The
interpolated calculated values will be designated as „calculated“
in the following paragraphs. Both entered and calculated values
will be stored upon leaving the arbitrary editor.
For signal frequencies
>
10 kHz the resolution will
decrease because not all points will fi t any more
in one signal period. For frequencies
<
10 kHz the
processor calculates the points necessary to fi ll one
signal period. Vertical points of equal amplitude are
added to the signal. Consequently, at low frequen-
cies a signal waveform will consist pre-dominantly
HINT
of calculated values.
STOP
1. The length of a signal period is independent of
the number of points and determined solely by the
signal frequency chosen.
2. The point at the beginning (X = 0) is always a re-
ference value and is automatically given the Y = 0 .
The point X = 0 can not be erased, its Y value can be
changed using the editor.
The arbitrary editor
The HM8131-2 editor allows to create waveforms or to change
stored waveforms. Before calling the editor it is necessary to
determine fi rst the size (4 or 16 k) of the signal to be edited. All
entries are made via the keyboard supported by the menus.
In order to get to the editor fi rst press the button [menu] in the
main menu. In the
main menu 1
go to the function “Arb“ and
answer the question Waveform size.
** WAVEFORM SIZE **
4096 Pts 16384 Pts
This will lead to the entry menu of the editor which offers the
functions: “New“, “Edit“, “Calc“, “Visu“:
** 4K ARB MENU ***
New Edit Calc Visu
New
ERASE all date ?
Yes No
This function initializes the selected memory erasing it. Only
the X = O Y = 0 point remains. In order to approve erasing the
question „Erase all waveform data“ YES/NO must be answered
with Yes. This should be only done in case a completely new
waveform is to be created.
STOP
The button “New“ should only be pressed if a new
signal is to be defi ned. Do not press it if a stored
signal shall only be changed.
Edit
Often it is not necessary to completely erase a waveform in order
to defi ne another one. It is possible to modify existing data or use
part of it. The menu [Edit] offers the possibility of erasing and
adding points. In order to modify a signal press the button [Edit].
The display will show in its top line the coordinates of the point to
be edited, also, whether this a reference or a calculated point.
X= 0 Ref Y= +0
Add Pref Next Del
Add: adds a point or modifi es an existing point
Prev: fetches the preceding point
Next: goes to the next point
Del:
deletes the selected point
STOP
The reference point X = 0 can not be erased, only its
Y coordinate can be changed. All signals will have
this X = 0 point.
Entry of reference points
X= 0 Ref Y= +0
Add Pref Next Del
-X=..... Y=.....
X< >Y
Select [Add] in order to add a reference point. Values are ente-
rered via the keyboard
and erased if necessary by pressing
ESC. The menu button X
Y selects between X and Y. After
inputting valid X and Y values pressing Ok will enter them.
Pressing [ESC] will erase them and allow a new input. After
pressng Ok the next point can be entered.
Do not forget to add a minus sign for negative in-
puts . The Y amplitude values extend from –2047 to
+2047 which equals 12 bits resolution of the output
voltage.
In the 20 V
pp
range a signal between –2047 and
+2047 will generate a no load output signal of
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±10
Vp.
This menu can be left pressing the [PREV] button.
** 4K ARB MENU ***
New Edit Calc Visu
If the input of all reference values has been completed select
[Calc] in the arbitrary menu in order to start the calculation of
the remaining points to fi ll a period. If desired choosing [Visu]
will display the points.
X= 0 Ref Y= +0
< cur > Pref Next
After initiating this function the coordinates of all points will be
shown in ascending order. The buttons Prev resp. Next allow to
access the former resp. following reference point. Interpolated
calculated points can be accessed by the knob. The increments
of the knob rotation are defi ned by the position of the cursor
under the X coordinate value.
1. If the cursor is located e.g. under the fi rst digit
of the X coordinate the knob will increment resp.
decrement in units of one, if under the 2
nd
digit in
units of ten etc.
2. Reference values are designated “Ref Y =“,
HINT
calculated values “Calc Y =“.
M a i n m e n u 1 a n d i t s f u n c t i o n s