Datasheet

23
5.2.14 Data Out of Range
As mentioned above, the parameters of frequency and amplitude have the specified
allowed range. Once out of range, the waveform generator will modify the setting
automatically, or modify the relative other parameters. Meantime, send an error message
with sound alarm. Data out of range won’t cause damage to instrument. But display
value maybe not the expected one, the generator will alarm again to remind you set it
again.
5.3 Frequency Modulation (FM)
In FM, carrier frequency 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 FM mode, displaying the FM sketch and
FM menu.
5.3.1 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.
5.3.2 Frequency Deviation
Press 〖Freq Dev〗softkey to set value of Freq Dev. The frequency deviation setting
represents the peak variation in frequency of the modulated waveform from the carrier
frequency. When the amplitude of the modulated waveform is at positive peak value, the
output frequency is equal to the frequency of the carrier plus the frequency deviation,
and when it is at the negative peak value, the output frequency is equal to the carrier
frequency minus the frequency deviation. Therefore, the frequency deviation setting
must conform to the following two conditions:
Carrier frequency – Frequency deviation > 0
Carrier frequency + Frequency deviation < upper limit frequency of waveform
generator
5.3.3 Modulating Waveform Frequency
After selecting FM, press 〖FM Freq〗softkey then enter the desired value. Usually the
modulating waveform frequency should be set far less than the carrier frequency.