5520A
Service Manual
6-58
Refer to Figure 6-9 for setup connections and connect the Calibrator Mainframe to the
Spectrum Analyzer. Adjust the Spectrum Analyzer so that it displays one peak across its
horizontal center line. The far right of the peak is fixed at the far right of the center line,
as shown below.
6-78. Adjusting the Leveled Sine Wave VCO Balance
Once you have completed the setup described above, perform the following procedure to
adjust the VCO balance for the leveled sine wave function.
1. Program the Calibrator Mainframe for an output of 5.5 V @ 600 MHz.
2. Set the Spectrum Analyzer to the parameters listed below.
Spectrum Analyzer Setup
Start Frequency 10 MHz
Stop Frequency 800 MHz
Resolution Bandwidth 30 kHz
Video Bandwidth 3 kHz
Reference Level 20 dBm
The Spectrum Analyzer will display a spur at 153 MHz. Refer to Figure 6-15 to
identify the spur.
3. You need to adjust the wave until the spur is at a minimum. To do this, slowly rotate
R1 (shown in the diagram) counterclockwise until the spur is at a minimum. As you
adjust it, the spur will move down the waveform, towards the right. As soon as the
spur is minimized, stop rotating R1. If you rotate it too far, the spur will reappear.
Once you have turned R1 to the point at which the spur is at a minimum, the signal is
balanced between the VCOs, and you have completed the adjustment.
R1
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Figure 6-15. Adjusting the Leveled Sine Wave Balance
6-79. Adjusting the Leveled Sine Wave Harmonics
The following procedure adjusts the harmonics for the leveled sine wave function.
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