The Arbitrary Editor (Arb-Editor); New; Edit - Hameg Instruments Hm8131-2 Handbuch

values where the time sequence of these "data" defines
the signal during one period. The amplitude values are
from - 2047 to + 2047. This corresponds to a resolution
of 12-Bit to adjust the output voltage. A signal between
- 2047 to + 2047 generates an output voltage of ±10V
(no load) when the amplitude range is 20V pp.
The signal period for the 4k word signal consists of 4,096
( 0 to 4095) points. For the 16k word it is 16,384 (0 to
16,383) points. Each individual "point" has a length of
25 ns (10Mhz max. signal frequency / 40MHz sampling
rate). From this results the optimum frequency of a signal
in the arbitrary mode of approximately 10kHz for a signal
with 4096 values in the X-axis. If the signal frequency is
increased to 100kHz correspondingly fewer (410 points)
are used per period.
To generate an arbitrary signal by specifying individual
points it is not necessary to enter all points for one signal
period. If fewer values are entered, the internal
uprocessor of the HM8131-2 will calculate the missing
points by interpolation between the given points
(Reference Points). It is sufficient only to give the
reference points to allow the calculation of other points.
However, the curve will be more accurate with more
given points.
Figure 4: "Construction" of an arbitrary signal
If the signal frequency is above 10kHz, the resolution of
the signal decreases because fewer points are given per
period. If the frequency is below 10kHz, the uprocessor
will calculate the necessary points to define one full
period. For this, support values of equal amplitude will
be added to the signal. At lower frequencies, a signal
period is predominantly defined by calculated values.
The length of a signal period is dependent on the
signal frequency and not on the number of points.
In summary, the construction of the shape of an arbitrary
function requires only a limited number of reference
points. The intermediary points are "calculated values".
The reference points and calculated points are stored
when the arbitrary editor is left.
Subject to change without notice
The point with the phase value of zero is always
a reference value with amplitude value of zero. This
data pair can be changed via the arb-editor.

The Arbitrary Editor (arb-editor)

The built-in arbitrary editor of the HM8131-2 offers the
possibility to generate either new signals or to vary signals
which are stored. Before the editor can be recalled the
size of the signal (4 k or 16 k) must be selected. Thereafter
all necessary data inputs are subsequently menu
supported and entered via the front panel key pad.
To access the arbitrary editor the "Menu"-key in the main
menu is pressed. Next, in "OPTIONS MENU 1" the
function "Arbit" is selected. The question "which
waveform size" must be answered with the desired
waveform size (4k or 16k). Subsequently, the input menu
of the arbitrary editor is opened.
The input menu offers the choice of the functions "New",
"Edit", "Calc" and "Visu".

New

The "New" function initializes the memory of the arbitrary
signal. Any present information is canceled by setting all
amplitude values to zero. Only the zero-phase point
remains in the memory (Y = 0). This function must be
confirmed with yes/no after the question "Erase all
waveform data" is displayed.
The "New" function should only be used when a
completely new signal is to be generated. This key
should not be used if the previously stored signal
is to be edited.

Edit

It is not always necessary to erase all signal data in the
memory before creating a new signal. It is also possible
to modify existing data for the creation of a new
waveform. The "Edit" function makes it possible to
modify a stored signal and to create a new signal based
on parts of the old data.
To modify existing data the "Edit" function in the ARB
menu has to be selected.
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