Giga-tronics Series 12000A, Operation Manual

Page: 99 / 238

Front Panel Operation
Publication 31231, Rev. J, October 2003 2-37
2.3.14 Internal Amplitude Modulation (Series 12500A/12700A Only)
Press
[AM]
to select the modulation parameter. Refer to the modulation parameters and specifications
in Chapter 1 for detailed information.
When Option 24 is installed in the instrument, the Amplitude Modulation Screen appears as shown in
Figure 2-22. The AM modes of Linear or Scan (Option 29) operate in the same manner as with an
external input (Refer to Section 2.3.13). Two new parameters appear: Waveform and Frequency. The
Scaling parameter is replaced with a depth parameter.
Figure 2-22: Amplitude Modulation Selection (Internal)
Waveform
The Waveform parameter has the following selections:
• Sinewave
• Squarewave
• Triangle wave
• Positive ramp
• Negative ramp
• Gaussian noise
• Modulation off
Each waveform (except the Gaussian noise) is calibrated to have the same peak-to-peak value. The noise
output has been bandwidth limited to about 150 kHz and has an peak-to-peak amplitude which is
approximately that of the other waveforms. Selecting the Off choice removes the signal from the amplitude
modulator but leaves the AM function itself turned on.
The AM Monitor connector on the rear panel provides an approximate 2 V
P-P
signal which matches the
selected waveform.
NOTE:
The Default waveform is “off” so a waveform needs to be selected to turn AM
on.
Frequency
This parameter field allows setting the modulating signal frequency. The allowable entry range is 0.01 Hz to
1 MHz. Note that the maximum frequency response of the AM functions is 150 kHz. The additional range of
the source is for compatibility with the internal FM source.
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