UTG1000A Series Function Generator User Manual
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panel. In positive signal level, FM output frequency is more than carrier wave frequency, while in
negative signal level, FM output frequency is less than carrier wave frequency. Low external signal level
has small deviation. For example, if the frequency offset is set to 1kHz and the external modulation
signal is +5V, FM output frequency will be the current carrier frequency plus 1kHz. When the external
modulation signal is -5V, FM output frequency will be the current carrier frequency minus 1kHz.
Modulation Shape Frequency Setting
When modulation source is internal, frequency of modulation shape can be modulated. After enabling
FM function, the default of modulation shape frequency is 100Hz. If need to change, press Carrier
Wave Parameter→ Modulation Frequency in turn, and the modulation frequency range is 2mHz to
50kHz. When modulation source is external, parameter list will hide the modulation shape 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 to 20Hz.
Frequency Deviation Setting
Frequency deviation represents the difference between frequency of the FM modulated waveform and
the carrier frequency. Settable range of FM frequency deviation is from 1μHz to the maximum of
current carrier wave frequency, and the default value is 1kHz. If need to change, press
Parameter→Frequency Deviation in turn.
Frequency deviation is less than carrier wave frequency. If frequency deviation value is set higher
than carrier wave frequency, the device will automatically set the offset value to the carrier
frequency’s maximum allowable frequency.
Sum of frequency deviation and carrier wave frequency is less than the allowed maximal frequency
of current carrier wave. If the frequency deviation value is set to an invalid value, the device will
automatically set the offset value to the carrier frequency’s maximum allowable frequency.
Comprehensive Example:
Make the instrument work in frequency modulation (FM) mode, then set a sine wave with 2kHz from
the internal of the instrument as a modulation signal and a square wave with frequency of 10kHz and
amplitude of 100mVpp as a carrier wave signal. Finally, set frequency deviation to 5kHz. Specific steps
are seen as following:
1)
Enable Frequency Modulation (FM) Function
Press Menu→Modulation→Type→Frequency Modulation in turn to start the FM function.
