4.7 Modulation Setting and Manipulation
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IM FG410-01EN
The internal modulation frequency cannot be set if the internal modulation waveform is
noise.
If the modulation type is FSK or PSK, the internal modulation waveform is fixed to a 50%
duty square wave, and the internal modulation waveform cannot be selected.
When an arbitrary waveform is selected for the internal modulation waveform, waveform
data simply decimated to 4096 points from the start is used as the modulation waveform in
case of the array format. When [RAW] is shown in the [Type] field in the arbitrary waveform
selection screen, the arbitrary waveform is in the array format. If the value in the [Size]
field is 17 KB or more, the original waveform size is larger than 4096 points. On the other
hand, when [Point] is shown in the [Type] field, the arbitrary waveform is in the control
point format. The arbitrary waveform in this format, the waveform is developed using 4096
points to maintain the waveform characteristics as much as possible. For details on the
arbitrary waveforms,
)
“2. CREATING ARBITRARY WAVEFORMS” in the Application
Instruction Manual.
f) To perform modulation with an external signal source
Set [Source] (modulation source) on the 2nd page of the setting screen to [Ext] (external).
The external modulation signal input terminal differs as follows according to the
modulation type.
■
When the modulation type is FM, PM, AM, AM(SC), OSFM, or PWM
Input the modulation signal to the external modulation/addition input terminal. The
modulation width setting is the value when the signal level is ±1 V. If the input level is
lower than ±1 V, keep it mind that the modulation width may become below the specified
modulation width.
When the external modulation/addition input terminal is used for external addition input,
the external modulation function cannot be used.
■
When the modulation type is FSK or PSK
Input the modulation signal (TTL level) to the external trigger input terminal.
The polarity can be set on the screen.
g) To start modulation
→
Modulation starts automatically. Resume with the [Start]
soft key.
When the modulated oscillation mode is set, modulated oscillation starts automatically.
However, if the modulation setting is improper, modulated oscillation will not start.
([Conflict!] is displayed in the top right part of the screen in this case.) When the [?] soft key
appearing at the left end is pressed, a message about the inappropriate setting is displayed.
Once the setting has been changed to an appropriate setting, modulated oscillation starts.
When modulation has been paused, it can be resumed by pressing the [Start] soft key.
h) To stop modulation
→
[Stop] soft key
Modulation can be paused.
When the [Stop] soft key is pressed during modulation, modulation stops and the carrier
signal is output without being modulated. The oscillation mode remains the modulated
oscillation mode.
