Teledyne LeCroy PXA125 - Manual (Page 79)

User Manual PXA125
ArbConnection 3-65
synthesizer is programmable using the Timer button in this group.
Arm The Arm group is really a semi-orphan function on the Trigger Panel.
This is the only function that actually will work in continuous mode
however, since the arm commands cause interruption of the PXA125
output and arm control is done with the trigger input, it was placed in
the trigger section of ArbConnection. While modifying Arm
commands, bear in mind that the instrument must be in continuous
mode only.
The arm function requires definition of breakpoints. To turn ARM on
and off, click on the State button. Select the Position LED to program
breakpoint position. The Positive on Negative slope options will
determine edge sensitivity for the trigger input.
There are two additional buttons at the right top corner of the Trigger
Panel. You can close the Trigger Panel by clicking on the Close key,
or return to the main panel and leave the Trigger Panel in the
background if you click on the “To Main Panel” key.
The Modulation
Panel The Modulation panel, as shown in Figure 3-9, is invoked either by
pressing the MOD button or “To Modulation Panel” button on the Main
Panel. The modulation panel provides access and control for a
number of functions: FM (frequency modulation), FSK (frequency shift
keying) and Sweep. The PXA125 can perform only one of these
functions at a time and ArbConnection will generate an error if you try
to change the state to on for more than one modulation option.
The functional groups in the Modulation Panel are divided to three
parts: Frequency Modulation, FSK and Sweep. These groups are
described below.
Frequency Modulation The Frequency Modulation group contains parameters for controlling
the sample clock. To turn the FM function on and off, click on the
State button in this group. There are sub-groups in the FM block:
Parameters, Shape, Mode and Slope.
Shape – Determines how the frequency will change. There are four
standard patterns that are built into the instrument: sine, triangle,
square and ramp, which could be selected from a built-in lookup
table. The arbitrary waveform shape must be loaded to the instrument
from an external application, or from the FM Composer. Click on the
button next to the required modulating waveform shape to select it.
Parameters – Allow adjustment of waveform parameters that are
selected from the Shape sub-group. Notice that the parameters are
changing as you select different shapes. To access the required
parameter, click on the button below parameters sub-group until the