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Signal source Internal/external
Select internal modulation/external modulation
Internal
modulation
Frequency
Set modulation wave frequency (2mHz~1MHz)
Modulation
amplitude
The modulating signal of internal modulation is a 50%
duty cycle square wave. Set modulation amplitude
range
External
modulation
Modulation
amplitude
When the external modulation is selected, the
modulation signal is input by the [Ext Trig] on the rear
panel. Only Modulation amplitude parameters need to
be set.
Note:
Modulation amplitude(High Z) can vary from 0V to 10V, the default value is 2V.
2.2.5 Frequency Shift Keying (FSK)
FSK modulation is to shift its output frequency between ET3325 preset values (Carrier
Frequency and the Hop Frequency). The frequency at which the output shifts between carrier
frequency and hop frequency is called FSK frequency. The frequency at which the output shifts
between these ET3325 frequencies is determined by the internal frequency generator or the
signal level on the rear-panel [Ext Trig] connector.
When the internal modulation is selected, the frequency at which the output shifts
between carrier frequency and hop frequency is determined by the specified FSK
frequency.
When the external modulation is selected, FSK frequency cannot be adjusted and is
determined by the signal level on the rear-panel [Ext Trig] connector. When a logic high
level is present, the carrier frequency is output. With a logic low level, the hop frequency
is output.
The carrier wave for FSK modulation can be set with the function keys
of
on the front panel.
Press
→ Type→ FSK and enter the interface as shown in Figure 2-25.