85
5.28. How to set the parameters of FM
1. Press
Mod
function button, then press
F1
to select Mod.
2. Press
F1
to switch Mod Type to FM. If the Carrier Waveform is not Sine, the
system will switch it to Sine automatically.
3. Press
button to display the waveform and parameters of the Carrier
Waveform. You can change the parameters, please refer to
“To Output Sine
Signals” on page 67
.
Press
button again to return to the Modulation mode
interface.
4. Press
F5
to select the source. If the source is External, use the
Modulation In
connector in the rear panel to input the external signal, then skip ahead to step (6).
If you choose Internal, continue to the steps below.
5. Press
F2
to choose Mod Shape, you can choose Sine, Square or Ramp.
6. Press
F3
to set Mod Frequency. The range is 2 mHz
～
20 kHz (Internal source
only).
7. Press
F4
to set FM Deviation. The Deviation should be less than the Carrier
Waveform Frequency.
Note
:
The Sum of the Deviation and the Carrier Frequency should be equal to or less than
maximum frequency of the selected function plus 1kHz.
For an External Source, the Deviation is controlled by the voltage Level of the signal
connected to the
Modulation In
connector in the rear panel. +5V corresponds to the
selected Deviation and -5V to the negative selected Deviation.
5.29. PM (Phase Modulation)
The modulated waveform consists of two parts: the Carrier Waveform and the Modulating
Waveform. The Carrier Waveform can only be Sine. In PM, the phase of the Carrier
Waveform varies with the instantaneous voltage level of the modulating waveform. The
user interface of the PM is shown as below.
Current Parameter
Carrier
Frequency
Carrier
Amplitude
Carrier Waveform
Modulating Waveform
Load
Phase Deviation
PM Frequency
Mod Type
Mod Shape
Source
Figure 0-18: The User Interface of PM
