Lf Power Level Accuracy (Most 8648B/C/D) - Agilent Technologies 8648A Operation And Service Manual

Adjustments
Manual Adjustments

LF Power Level Accuracy (Most 8648B/C/D)

8648B/C Frequency Range
Early versions of the 8648B and 8648C have a frequency range that begins at 100 kHz
rather than 9 kHz. If the DUT has a frequency range that begins at 100 kHz, do not run
this adjustment.
Description
This adjustment covers the frequency range of 9 to 100 kHz and the dynamic range of 0 to
−100 dBm. Initially, the spectrum analyzer is checked to verify that its noise floor and any
residuals are at least 20 dB below the lowest signal measured. If a residual is detected, the
frequency is shifted plus or minus 25 Hz. If the noise floor is too high, the adjustment is
exited.
Signal levels between 0 and -40 dBm are measured directly with a digital voltmeter
(DVM). Lower signal levels are measured using the spectrum analyzer. All spectrum
analyzer measurements are relative to the −40 DVM measurement.
Required Test Equipment
• DVM
• Spectrum Analyzer
• 6 dB Attenuator
• 50Ω Feedthrough
Procedure
Figure 7-31. LF Power Level Accuracy Test Setup for Power Levels of ≥ −40 dBm
7-32