78 UTG2000B Series
Figure 3 - 10 Select modulation source
Internal source
In case of internal modulation source, modulation wave can be sine wave, square wave, rising ramp
wave, falling ramp wave, arbitrary wave and noise, and is sine wave by default. After you use
DSBAM function, you can see that modulation wave is sine wave by default. You can change it with
multi-functional knob on interface for using amplitude modulation function or by pressing Param
→
ModWave
●
Square wave: duty ratio is 50%
●
Rising ramp wave: symmetry degree is 100%
●
Falling ramp wave: symmetry degree is 0%
●
Arbitrary wave: when selecting arbitrary wave as modulation waveform, function/arbitrary
waveform generator limits length of arbitrary wave to 4Mpts by automatic test count.
●
Noise: white Gaussian noise
External source
In case of external modulation source, modulation wave and frequency will be hidden in parameter
list, when an external waveform will be used to modulate carrier waveform.
DSBAM 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
When modulation source is internal, frequency of modulation wave can be modulated. After
enabling DSBAM function, default of modulation wave frequency is 100Hz. Press Param
→
ModFreq to change. Modulation frequency range: 2mHz~1MHz. When modulation source is
external, parameter list will hide the modulation wave option and modulation frequency option,
and carrier waveform will be modulated by an external
waveform. The range of modulation signal input from external is 0Hz~ 20Hz.
Comprehensive example
First make the instrument run in DSBAM mode, and then set an internal sine wave of 1kHz as
modulation signal and a square wave with frequency of 2kHz, amplitude of 2Vpp. The specific steps
are as follows:
1)
Use DSBAM function
Summary of Contents for UTG2122B
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