I read in !emc-pstc that [email protected] wrote (in <39029.198.246.16. [email protected]>) about 'Q. on Res Bandwith performace traceabiity' on Sun, 31 Aug 2003:
>As the professors would >say, it is left to the student to prove that 3 dbm = 6 dbv through the >formula P = EE/R. Except that it ABSOLUTELY ISN'T!!! Either way I interpret your ambiguous statement. If you mean absolute values, 3 dBm = 2 mW. 6 dB(V) = 2 V. OK, they happen to be equal in a 2 kohm system, but who has one of those? If you mean relative values, a difference of 3 dB in power level (a 'difference of 3 dBm' is a difference of 2 mW, which is not what you mean, if you think about it) is equal to a ratio of 2 in watts, which is, in a constant-resistance system, equal to a ratio of 1.414... in volts, which is 3 dB in voltage level. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ 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] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
