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Figure 4- 100 Select modulation source
1) Internal source
When using an internal modulation source, modulation wave can be sine wave, square wave, ascending sawtooth wave,
descent sawtooth wave, arbitrary wave and noise, and is sine wave by default. After you use SUM function, the
modulation wave is sine wave by default. You can change it with the multi-functional control on the interface for using
amplitude modulation function or by pressing Wave.
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Square wave: duty ratio is 50%
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Sawtooth wave: degree of symmetry is 0.10%
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Arbitrary wave: when selecting arbitrary wave as modulation waveform, function/arbitrary waveform generator
limits length of arbitrary wave to 32Mpts by automatic test count.
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Noise: white Gaussian noise
2) External source
When using an external modulation source, modulation wave and frequency will not show in the parameter list, when an
external waveform will be used to modulate carrier waveform. SUM depth is controlled by ±5V signal level on external
analog modulation input terminal (Modulation In connector) of back panel. For example, if modulation depth in parameter
list is set to be 100%, SUM output amplitude is the maximum when external modulation signal is +5V and the minimum
when external modulation signal is -5V.
Set frequency of modulation wave
The frequency of modulation wave can be set in case of internal modulation source. After you use SUM function, the
default frequency of modulation wave is 10kHz. You can change it with the multi-functional control and direction keys on
the interface for using amplitude modulation function or by pressing Freq. The range of modulation frequency is
2mHz~100kHz. When using an external modulation source, modulation wave and frequency will not show in the
parameter list, when an external waveform will be used to modulate carrier waveform. The frequency range of modulation
signal of external input is 2mHz~20kHz.