Fm Commands Overview - Agilent Technologies 33250A User Manual

FM Commands
Use the APPLy command or the equivalent FUNC, FREQ, VOLT, and
VOLT:OFFS commands to configure the carrier waveform.
FM:SOURce {INTernal|EXTernal}
FM:SOURce?
Select the source of the modulating signal. The function generator will
accept an internal or external modulation source. The default is INT.
The :SOUR? query returns "INT" or "EXT".
• If you select the External source, the carrier waveform is modulated
with an external waveform. The frequency deviation is controlled
by the ±5V signal level present on the rear-panel Modulation In
connector. For example, if you have set the deviation to 100 kHz
using the FM:DEV command, then a +5V signal level corresponds to a
100 kHz increase in frequency. Lower external signal levels produce
less deviation and negative signal levels reduce the frequency below
the carrier frequency.
FM:INTernal
:FUNCtion {SINusoid|SQUare|RAMP|NRAMp|TRIangle|NOISe|USER}
:FUNCtion?
Select the shape of the modulating waveform. Used only when the
Internal modulation source is selected (FM:SOUR INT command). You can
use noise as the modulating waveshape, but you cannot use noise, pulse,
or dc as the carrier waveform. The default is SIN. The :FUNC? query
returns "SIN", "SQU", "RAMP", "NRAM", "TRI", "NOIS", or "USER".
• Select "SQU" for a square waveform with a 50% duty cycle.
• Select "RAMP" for a ramp waveform with 100% symmetry.
• Select "TRI" for a ramp waveform with 50% symmetry.
• Select "NRAM" (negative ramp) for a ramp waveform
with 0% symmetry.
• If you select an arbitrary waveform as the modulating waveshape
("USER"), the waveform is automatically limited to 8K points.
Extra waveform points are removed using decimation.
Chapter 4 Remote Interface Reference
Frequency Modulation (FM) Commands
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