Adjusting The Leveled Sine Wave Function; Equipment Setup; Adjusting The Leveled Sine Wave Harmonics - Fluke 5520A Service Manual

5520A
Service Manual

6-138. Adjusting the Leveled Sine Wave Function

There is one adjustment procedure that need to be made for the leveled sine wave
function. The procedure adjusts the harmonics.

6-139. Equipment Setup

This procedure uses the spectrum analyzer. Before you begin this procedure, verify that
the Calibrator Mainframe is in leveled sine wave mode (the Levsine menu is displayed),
and program it to output 5.5 V p-p @ 50 MHz. Press
Refer to Figure 6-24 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 centerline. The far right of the peak is fixed at the far right of the centerline,
as shown below.

6-140. Adjusting the Leveled Sine Wave Harmonics

This procedure should only be used for adjusting the leveled sine wave
harmonics. Do not use this procedure as a verification test. The
specifications in this procedure are not valid for verification.
Set the Spectrum Analyzer to the parameters listed below.
Spectrum Analyzer Setup
Start Frequency
Stop Frequency
Resolution Bandwidth
Video Bandwidth
Reference Level
Use your Spectrum Analyzer's Peak Search function to find the desired reference signal.
The Analyzer should show the fundamental, and second and third harmonics. The
harmonics need to be adjusted so that the second harmonic is at -34 dBc and third
harmonic should typically be greater than or equal to -39 dBc as shown in Figure 6-29.
To adjust the harmonics, adjust R8, as shown in Figure 6-29 until the peaks of the
second and third harmonic are at the correct dB level. You may find that you can place
the second harmonic at -34 dBc but the third harmonic is less than -39 dBc. If this is the
case, continue adjusting R8 until the third harmonic is at –39dBc and the second
harmonic is greater than or equal to –34dBc The second harmonic will fluctuate, but
there is a point at which both harmonics will be at the correct decibel level.
6-108
Oscilloscope Mainframe and Sampling Head (Tektronix 11801 with SD-22/26 or
Tektronix TDS 820 with 8 GHz bandwidth)
10 dB Attenuator (Weinschel 9-10 (SMA), or Weinschel 18W-10, or equivalent)
Cable provided with SC300
Spectrum Analyzer (Hewlett-Packard 8590A)
Note
50 MHz
500 MHz
3 MHz
3 kHz
20 dBm
to activate the output.