Teledyne LeCroy PXA125 - Manual (Page 73)

User Manual PXA125
ArbConnection 3-59
Sequence Advance The Sequence Advance group provides control over advance modes
for the sequence generator. Advance options are: Auto, Stepped,
Single and Mixed. Refer to the PXA125 operation instructions to find
out more when and how to use these advance modes. You should be
careful while selecting modes because it is possible to cause settings
conflict, for example, if you select the Single option and you forgot to
change your trigger mode to Triggered.
The Sequence advance group lets you also select the source for
advancing the sequence steps. Description of the various advance
sources is given below.
External – selects the TRIG IN input as the advance source. Note
that this option will affect the generator only when it is placed in
operational mode that requires trigger stimuli.
Internal – disables the TRIG IN input and routes an internal trigger
generator to the trigger advance circuit.
STAR – connects the trigger source to a backplane STAR line. This
line serves as common trigger line to all modules.
TTLT0 to TTLT7 – connects the trigger source to one of eight
backplane trigger lines.
Besides the grouped controls, there are five other buttons available
on the Arbitrary & Sequence Panel. These buttons provide access to
(from top to bottom) Wave Composer, Sequence Table, Segment
Table, Main Panel. The last button removes the Arbitrary & Sequence
Panel from the screen. The Wave Composer will be discussed
separately in this chapter. The Segment and Sequence Tables are
described below.
Using the Segment
Table
If you want to learn more about segment control, you should refer to
Chapter 4 of this manual. In general, the PXA125 can generate
arbitrary waveforms but before it can generate anything, the
waveforms have to be downloaded to the instrument from a host
computer. The waveforms are downloaded as coordinates and are
stored in the PXA125 is a place designated as “waveform memory”.
The waveform memory has a finite size of 2Meg.
Having such a long memory to store waveforms does not necessarily
mean that you have to use the entire memory every time you
download a waveform. On the contrary, the PXA125 allows
segmentation of the memory so that up to 4096 smaller waveforms
could be stored in the waveform memory. There are two ways to
divide the waveform memory to segments: Define a segment and