Creating A Frequency-Modulated Output Signal - Fluke 9640A Series Instruction Manual

Creating a Frequency-Modulated Output Signal

Use the following procedure to create a frequency-modulated output signal and, if
required, to define the incremental step values by which the frequency, level, modulation
rate and deviation of the output signal can be increased and decreased. Refer to Table
3-17 for a list of the fields available on the Modulation screen and the limits associated
with each field.
1. Press .
2. Press the Modulation Select soft key to expand the selections at the bottom of the
screen.
3. Press the FM soft key to activate the FM Modulation screen.
4. Select the Frequency field, and enter the desired output frequency.
5. If a frequency step is required, press the Frequency soft key again until a Freq Step
field appears at the bottom of the screen.
a. Select the Freq Step (Step Size) field.
b. Enter the desired frequency step in the field.
6. Select the Level field and enter the desired output level.
7. If a level step is required, press the Level soft key again until a Level Step field
appears at the bottom of the screen.
a. Select the Level Step (Step Size) field.
b. Enter the desired level step in the Level Step field.
8. Select the Mod Rate field and enter the desired output rate.
Notice that the Mod Rate field includes a definition of the modulating waveform,
Sine, or External. To select a specific waveform proceed as follows:
a. Press the Mod Prefs soft key.
b. Select the FM Mod Waveform field.
c. Select the appropriate waveform (Sine or External).
d. Enable, if required, the Modulation Trigger Output, Rising or Falling Edge.
e. If an External Modulation waveform is in use, select either AC or DC coupling
Return to the FM Modulation screen by pressing the Exit soft key.
f.
9. If a rate step is required, press the Rate soft key again until a Rate Step field appears
at the bottom of the screen.
a. Select the Rate Step (Step Size) field.
b. Enter the desired rate step in the Rate Step field.
10. Select the Deviation field and enter the desired deviation frequency. If External
Modulation is in use, the entry is the required deviation sensitivity value in Hz, kHz
or MHz per Volt.
11. If a deviation step is required, press the Deviation soft key again until a Dev Step
field appears at the bottom of the screen.
a. Select the Dev Step (Step Size) field.
b. Enter the desired deviation step in the Dev Step field.
Local Operation
Operating the Instrument
3-47
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