User Manual

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. This is to say, when the modulation

depth is at 0, carrier amplitude is a half of amplitude setting.

5.4.3 Modulating Waveform Frequency

Press 〖AM Freq〗softkey to set the value of AM frequency. Generally speaking, the modulating

frequency is always lower than carrier frequency.

5.4.4 Modulating Waveform Shape

Press 〖Shape〗softkey then select ‘Shape’ to enter the desired wave. Press 【Waveform】 key, then

select one of most waveforms in above as modulating waveform. Finally, return to FM menu.

5.4.5 Modulating Source

The waveform generator will accept an internal or external modulation source for AM. 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 controlled by

the ±5 V signal level present on the rear-panel Modulation In connector.