Phase Modulation (Pm) - Rigol DG900 Pro Series User Manual

Modulation
Frequency Deviation
It represents the peak variation in frequency of the modulated waveform from the
carrier frequency. Click or tap the Freq Dev input field to set the frequency deviation.
The minimum frequency deviation is 0 Hz.
• For FM, the frequency deviation must always be less than or equal to the carrier
frequency minus 1 μHz.
• The frequency deviation plus the carrier frequency must be less than or equal to
the selected carrier's maximum frequency.
When an external modulation source is selected, the frequency deviation is controlled
by the ±5 V signal level on the rear-panel [AUX IN/OUT] connector. For example, if
the frequency deviation is set to 1 kHz, the +5 V signal level corresponds to a 1 kHz
increase in frequency. Lower external signal levels produce less deviation and
negative signal levels reduce the frequency below the carrier frequency.
6.3

Phase Modulation (PM)

In Phase Modulation (PM), a modulated waveform consists of a carrier waveform and
a modulating waveform. The phase of the carrier waveform is varied by the
instantaneous voltage of the modulating waveform. In the "Modulation Setting
Interface" (
"PM" and set its parameters.
Carrier Waveform
Available PM carrier waves include sine (default), square, ramp, and Arb (except DC).
Click or tap the "Wave Type" drop-down button or press the corresponding front-
panel waveform selection key to select the desired carrier waveform shape and access
the setup interface. To configure different carrier waveforms, please refer to
Continuous
Modulating Waveform
The instrument accepts an internal or external signal as the modulation source. Click
or tap the Source drop-down button to select "Internal" or "External".
• Internal Source
After "Internal" is selected, you can click or tap the Shape drop-down button to
select the modulating waveform shape. Available shapes include:
-
-
-
-
DG900 Pro User Guide
52
Figure 6.1
), click or tap the "Modulation Type" drop-down button to select
.
Sine
Square with 50% duty cycle
Triangle with 50% symmetry
UpRamp with 100% symmetry
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