![background image](http://html2.mh-extra.com/html/racal-instruments/3153/3153_user-manual_3135464026.webp)
User Manual 3153
Getting Started 1-13
Arbitrary (User)
Waveforms
The arbitrary waveform memory is capable of storing one or more user-
defined waveforms. As was discussed before, and unless ordered
differently, the Model 3153 is supplied with 512k, 2 Meg and 2 Meg
memory banks with channels 1, 2 and 3, respectively. With the 8 Meg
option, there are up to 8 Meg points that can be allocated to one single
waveform. On the other hand, there is no need to use the entire memory
for only one waveform. The memory can be divided into smaller
segments loaded with different waveforms. The instrument can be
programmed to output one segment at a time.
Loading data to arbitrary waveform memory can be a time-consuming
task, especially if all 8 Meg points are loaded in one shot. The Model
3153 utilizes the VXIbus shared memory concept that speeds data
transfer from host computer. In this mode, the memory bank is
disconnected from the CPU circuit and re-routed to the bus on the back
plane for direct memory accessing by the host computer.
The Model 3153 has separate arbitrary waveform memories for each
channel. Each channel can be loaded with different waveforms.
Channels are not limited by the number of segments and by the shape
of the waveforms regardless if the channels operate separately or in
master-slave mode.
Sequenced
Waveforms
The sequence generator is a very powerful tool that lets you link and
loop segments in any way you desire. As a simple example of a
sequenced waveform, look at Figures 1-3 through 1-5. The waveforms
shown in these figures were placed in memory segments 1, 2 and 3,
respectively. The sequence generator takes these three waveforms links
and loops them in a predefined order to generate the waveform shown
in Figure 1-6.
The sequence circuit is useful for generating long waveforms with
repeated sections. The repeated waveform has to be programmed once
and the repeater will loop on this segment as many times as selected.
When in sequenced mode, there is no loss of time between linked or
looped segments.
The Model 3153 has three separate sequence generators – one for
each channel. Each sequence generator is dedicated to its own
channel, even in master-slave mode.
Sequence tables must be loaded to the generator before sequenced
waveforms can be generated. The data for the sequence table is first
prepared on external platforms, then downloaded to the generator.
Downloading long sequence table may take some time therefore, such
table can be downloaded to the instrument using direct memory access
(DMA) routines. Figure 1-7 shows an example how to define a sequence
using WaveCAD.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com