PeakTech 4105 Bedienungsanleitung Seite 99

5.3 Frequency Modulation (FM)
A modulated waveform consists of a carrier waveform and a modulating waveform. In FM, the
frequency of the carrier is varied by the instantaneous voltage of the modulating waveform. Press
【Modulate】key to select the mode, the default is FM.
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. Generally speaking,
modulating waveform frequency is always less than the carrier frequency.
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