Datasheet

5.3.4 Modulating Waveform Shape

Press 〖Shape〗softkey then select ‘Shape’ to set. Press 〖Waveform Menu〗to select

the desired waveforms in above table as modulating waveform. Finally, return to FM

menu.

5.3.5 Modulating Source

The waveform generator will accept an internal or external modulation source for FM.

Press 〖Source Int/Ext〗softkey. It’s available to set modulating frequency and modulating

waveform if ‘Internal’ source is selected. But if you select External source, the carrier

waveform is modulated with an external waveform. The frequency deviation is same as

actual value if amplitude 5Vpp, dc offset 0Vdc signal level present on the rear-panel

<Mod In> connector.

5.4 Amplitude Modulation (AM)

In AM, carrier amplitude varies with the instantaneous voltage of modulating waveform.

Press 【Modulate】key to enter into the Modulating output mode, the working mode

displays as Mod. Then press〖Type〗and select AM mode, displaying the AM sketch and

AM menu.

5.4.1 Set Carrier

Firstly, set the shape, frequency, amplitude and offset of Carrier Waveform. You can

select most waveforms from above table to be carrier, but some waveforms are not

available.

5.4.2 Modulation Depth

Press〖Depth〗softkey then set desired depth using knob or numeric keypad. The

modulation depth is expressed as a percentage and represents the extent of the

amplitude variation. If the maximum amplitude of modulating carrier is expressed as

Amax, the minimum amplitude Amin, setting value of amplitude as A and modulation

depth as M, the relationship among the four factors are expressed as following:

Amax＝(1+M)×A/2.2 Amin＝(1-M)×A/2.2

Therefore,

M＝（Amax－Amin）×1.1/A

If modulation depth at 120%, then Amax=A and Amin= -0.09A. If modulation depth at

100%, then Amax=0.909A and Amin=0. If modulation depth at 50%, then Amax=0.682A

and Amin=0.227A. If modulation depth at 0%, then Amax=0.455A and Amin=0.455A.