Tabor Electronics 5251, User Manual

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4
Remote Programming Reference
Modulated Waveforms Control Commands
4-45
FM Modulation
Programming
Use the following command for programming the FM parameters.
FM control is internal. There are two types of waveforms that can
be used as the modulating waveforms: Standard and Arbitrary. The
standard waveforms are built in a library of waveforms and could be
used anytime without external control. The arbitrary waveforms
must be loaded into a special FM arbitrary waveform memory and
only then can be used as a modulating waveform.
FM:DEViation<deviation>(?)
Description
This programs the deviation range around the carrier frequency. The deviation range is always symmetrical
about the carrier frequency. If you need non-symmetrical deviation range, you can use the arbitrary FM
composer screen or an external utility to design such waveforms.
Parameters
Name Range Type Default Description
<deviation> 10e-3 to
100e6 Numeric 100e3 Programs the deviation range around the carrier
frequency in units of Hz.
Response
The 5251 will return the present deviation frequency value. The returned value will be in standard scientific
format (for example: 100mHz would be returned as 100e-3 – positive numbers are unsigned).
FM:FUNCtion:SHAPe(SINusoid|TRIangle|SQUare|RAMP|ARB}(?)
Description
This command will select one of the waveform shapes as the active modulating waveform.
Parameters
Name Type Default Description
SINusoid Discrete SIN Selects the sine shape as the modulating waveform
TRIangle Discrete Select the triangular shape as the modulating
waveform
SQUare Discrete Select the square shape as the modulating waveform
RAMP Discrete
Selects the ramp shape as the modulating waveform
ARB Discrete
Selects an arbitrary waveform as the modulating
shape. The waveform must be designed and
downloaded to the FM arbitrary modulating waveform
memory before one can use this option. Information
on how to create and download FM arbitrary
waveforms is given later in this chapter.
Response
The 5251 will return SIN, TRI, SQU, RAMP, or ARB depending on the selected function shape setting.