Teledyne LeCroy PXA125 - Manual (Page 190)

User Manual PXA125
Programming Reference 4-72
given in the following paragraphs.
Arbitrary Memory
Management
The arbitrary memory in comprised of finite length of points. The
maximum size arbitrary waveform that can be loaded into memory
depends on the option that is installed in your instrument. The various
options are listed in Chapter 1 of this manual. If you purchased the
PXA125 with in its basic configuration, you should expect to have 2
Meg words to load waveforms.
Waveforms are created using small sections of the arbitrary memory.
The memory can be partitioned into smaller segments (up to 4096)
and different waveforms can be loaded into each segment, each
having a unique length. Minimum segment size is 16 points.
Information on how to partition the memory, define segment length
and download waveform data to the PXA125 is given in the following
paragraphs.
Downloading
Arbitrary
Waveforms
There are two ways to download arbitrary waveform data points into
the memory. You can use Wave Composer utility in ArbConnection to
program segments and their size, create the waveform on the screen
and then with a click of a button, download the entire waveform to the
instrument. On the other hand, if you are writing your own application,
you’ll need to use the SendComand() and SendBlock() functions.
Information on these functions is given at the beginning of this
chapter. You can follow the general guidelines below to download
waveforms to the instrument. The following example assumes
segment 1 having 1000 points.
1. Use the function SendCommand() to program trac:sel 1. This
command will make segment number 1 active. Anything that
you will download to the PXA125 will be downloaded to the
active segment, in this case – segment 1.
2. Use the SendCommand() to program trac:def 1,1000. This
command defines the size of segment 1, in this case – 1000
waveform points.
3. Use the function SendBlock() to send waveform data points to
the PXA125. You can use this function in two ways: 1) You can
generate and save an external file with the waveform
coordinates and then call this function with the path to your file,
or 2) you can build the coordinates into your function, as
described earlier in this chapter.
After you download the waveform coordinates to the instrument,
you’ll have to change the waveform mode to arbitrary (USER) and
set the sample clock frequency to that the output frequency will meet
with your requirements. Additional information on the commands
used for arbitrary waveform management is given below.