Improved Subjective Weighting Function. ANSI C63.19 Working Group Submitted by Stephen Julstrom for October 2, 2007. The Goal of Subjective Weighting.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Improved Subjective Weighting Function
ANSI C63.19 Working Group
Submitted by Stephen Julstrom
for October 2, 2007
The Goal of Subjective Weighting
Telecoil Mode Test Results Using A-Weighting
(In viewing the graphs, the 80-90% range in the distribution is the most significant for comparison, since it includes the most subjects while excluding the outliers in the top few percent.)
Indicators for a New Weighting Function
A-Weighting Alternate Weighting
3 kHz, 2nd order
D.F. = 0.707
RMS Level Measurement
2.6 Hz, 2nd order
D.F. = 0.81
4 msec TC
Slow, averaging response such as VU meter dynamics for steady state reading
550 msec TC
(equivalent to 2 msec TC w/linear level measurement)
Similar to CISPR Quasi-Peak Detection
Plausible Justifications for the Specific Changes
Telecoil Mode Test Results Using Alternate Weighting
The previous ~10 dB spread in the 80-90% areas is reduced to ~4 dB, with much of that being random variation, rather than consistent bias related to noise type.
Applicability to RF Interference
Although derived from telecoil mode study results, the new modified weighting function should likely have equal applicability to RF interference, allowing a common weighting method to be used for both measurements.
Addendum: Specific Changes in Measured Levels