15
SETTING MODULATION SHAPE FREQUENCY
•
Modulating frequency is available to set up when you select internal modulation
source.
•
With AM enabled, the modulation frequency defaults at 100Hz. To change
the frequency, use the multipurpose knob and direction buttons or press
Params→ModFreq
softkeys to select from 50kHz to 2MHz.
•
If the source is chosen externally, modulation shape and frequency options won’t
show on the parameter list.
•
In this case, the carrier is modulated by an external waveform at a frequency of
0Hz to 20kHz.
Setting Modulation Depth
•
Modulating depth is expressed with a percentage and represents amplitude
variation.
•
AM amplitude depth can be selectable from 0%~120%, the default value is 100%.
•
When modulating depth is at 0%, the output amplitude is a constant value (half of
the set value of carrier amplitude).
•
At 100%, the output amplitude varies according to the modulation shape. At
greater than 100%, the Generator will not output one exceeding ±5V Peak-Peak
voltage (into 50Ω terminal).
•
To modify modulation depth, use the multipurpose knob and direction buttons or
press
Params→Depth
.
•
When you select external source for the modulation, the output amplitude is also
controlled by ±5V signal level presented on the External Analogue Modulation
Input (Modulation In) Connector.
•
For instance, if modulating depth in the parameter list has been set to 100% then
when the modulation signal is +5V, AM output is at the maximum amplitude; at -5V,
AM output will go down to the minimum amplitude.
Applications
•
Firstly, enable AM mode of the Generator.
•
To set a 200Hz sine wave from internal source as modulation signal with a square
wave (200mVpp, 45% duty cycle, 10kHz) as the carrier and modulating depth at
80%, follow the steps below:
1) Enabling AM function
•
Press
Menu→Mod→Type→AM
to enable the
AM function.
•
For example, modulation depth in the parameter list has been set to 100%,
when +5V external modulation signal is applied, AM output amplitude goes up to
maximum value; AM output amplitude goes down to the mimimum with external
signal applied at -5V.
