Product Manual

Arbitrary Waveform Generation
Selecting and Outputting Arbitrary Waveforms 9
9-3
2. Modifying that waveform using the various editing capabilities to get exactly the
waveform required.
These steps are fully described in the Creating New Waveforms and Modifying Arbitrary
Waveforms sections which follow.
Waveform creation using waveform design software also consists of two steps:
1. Creating the waveform using the software on a PC.
2. Downloading the waveform to the generator via the RS232 or GPIB interface.
Certain constraints apply to the overall operation of the generator during creation and
modification of an arb waveform on the instrument; these ensure proper management of
the arb waveforms and avoid contentions, particularly in multi-channel instruments. The
constraints are mentioned in the individual sections which follow but are summarized
here.
1. On multi-channel instruments all the channels must be running in continuous mode to
allow arb creation or modification. Summing and modulation of channels is allowed.
2. Arb waveforms are created and mostly edited in the non-volatile backup memory; up
to 100 waveforms can be stored subject to the memory limitation of 256 kBytes. Any
of these waveforms can be called into a channel’s memory by selecting them to run
as an arb or as part of an arb sequence, up to the channel’s limit of 65,536 points.
During editing, changes are made to the waveform in non-volatile memory and are
then copied to all the channels where that waveform is used. The exceptions to this
are amplitude, offset and block copy changes which are initially made only to the
waveform copy of the channel currently selected; the changes are copied to the non-
volatile back-up memory (and then to any other channels using that waveform) when
the parameter edit is confirmed with the
save soft-key.
3. A waveform cannot be deleted from a channel’s memory if it is running on that
channel.
4. Waveforms must be deleted from the channel’s memory before they can be deleted
from the back-up memory.
5. If an arb waveform sequence is running no waveforms can be deleted from that
channel, whether they are used in the sequence or not.
6. A waveform used by a non-active sequence can be deleted but the sequence will not
subsequently run properly and should be modified to exclude the deleted waveform.
You will be reminded of the above constraints by a warning or error message in the
display if you attempt an illegal operation.
Selecting and Outputting Arbitrary Waveforms
At switch-on, assuming factory default settings, any arbitrary waveforms already created
will only be stored in the non-volatile back-up memory. To run an arbitrary waveform it
is necessary to select it from the list in back-up memory.
Press the
ARB key to see the list, on the ARBS screen, of all arbitrary waveforms held
in back-up memory.