I read in !emc-pstc that Rob Keller <[email protected]> wrote (in <[email protected]>) about 'Acoustic Pressure Test' on Tue, 13 Apr 2004: >I had a client who was running the Acoustic Pressure Test described in UL/CSA >60950-01-03. The question he posed was concerning the A-wieghted sound that is >suppose to be measured. He wondered what is the difference between an A- >weighted sound and a non A-weighted sound. Does anyone have an answer?
A-weighting is a frequency-weighting normally applied to the *measuring device*, not the signal source. I can't comment further on this because the text in the UL/CSA standard doesn't seem to be in IEC/EN 60950-1. The weighting characteristic is defined in IEC 61672, and there is a corresponding ANSI standard. Originally, the weighting was designed to follow the frequency response of the human ear for a loudness of 40 phons, but it is now used for general noise measurements at any sound level, except certain special sounds, such as aircraft noise. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
