UTG2000B Series 35
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 wave Frequency Setting
When modulation source is internal, frequency of modulation wave can be modulated. After
enabling FM function, the default of modulation wave frequency is 100Hz. If need to change, press
Param
→
ModFreq in turn, and the modulation frequency range is 2mHz to 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 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
1μ
Hz to the maximum
of current carrier wave frequency, and the default value is 1kHz. If need to change, press Param
→
FreqDev in turn.
Frequency deviation
≤
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.
frequency devcarrier wave frequency must
≤
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:
3) Enable Frequency Modulation (FM) Function
Press Menu
→
Mod
→
Type
→
FM in turn to start the FM function.
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