Fluke Biomedical RF303 - Manual (Page 67)

B-1
Appendix B
Interpretation of Fluctuating
Readings
Interpretation of Fluctuating Readings
The RF303 Analyzer incorporates an accurate digital measurement system that
operates in three modes. The first measurement mode (default mode) utilizes a
relatively short sampling time and does not filter or average ESU output. The
two selectable measurement modes utilize longer sampling times that average
ESU output. When using the default measurement mode, you may observe
some ESU output readings that fluctuate plus or minus 10% or more,
depending on the unit under test. This is normal operation and is not indicative
of a problem with the Analyzer.
When fluctuating readings are observed, take note and determine if this is
normal behavior for the ESU under test, or if this behavior is a sign of a
problem.
• Older ESUs may have unstable output due to old technology or
design. This is typical and is acceptable, based on the manufacturer’s
limits.
• Many newer-generation ESUs utilize instantaneous feedback loops,
which constantly adjust the output and can cause an oscillating effect.
This result is also satisfactory and is considered normal for these
devices.
• In some cases, fluctuating ESU power output is evidence of a
problem. Fluctuating output on some ESUs may indicate the
weakening of output from power transistors or other ESU ailments
and is not acceptable.
If an ESU normally has fluctuating output, then operating the Analyzer in one
of the Signal Averaging Modes (SAM) may be desirable. SAM significantly
reduces fluctuating readings on the display of the Analyzer making it easy to
read an average value.