No. You aren't applying the rule correctly. As I stated earlier: log a*b = log a + log b log b^n = n log b Combining, it is clear that log (a*b^n) = log a + n log b.
---------- >From: [email protected] >To: [email protected], [email protected] >Subject: duty cycle closure >Date: Fri, Oct 19, 2001, 2:33 PM > > > Going back to fundamentals -- > > Given a = duty cycle = average power > and define "^2" = "squared" > > Then P[ave] = a P[ref] > > P = V^2/R > > V[ave]^2/R = aV[ref]^2/R, the Rs cancel leaving > > V[ave]^2 = aV[ref]^2 > > 10 log(V[ave]^2) = 10 log (aV[ref]^2), which is equivalent to > > 20 log (V[ave]) = 20 log (aV[ref]) > > = 20 log (a) + 20 log (V[ref]) > > In the last equation one sees the duty cycle isolated as "20 log (a)" when > referring to power in terms of voltage. > > Best regards, > > Don Umbdenstock > Sensormatic > > >> ---------- >> From: Doug McKean[SMTP:[email protected]] >> Reply To: Doug McKean >> Sent: Friday, October 19, 2001 2:41 PM >> To: [email protected] >> Subject: Re: Is This Right? >> >> >> > >> > More to the proof discussion launched by the duty cycle question, >> given >> > >> > > dB = 10 log (P1/P2) >> > > >> > > Let "a" be the duty cycle ratio, with 0<a<1, so that P1 = aP2. >> > > >> > > Then dB = 10 log (aP2/P2) = 10 log (a). Eq. >> > > (1) >> > > >> > If 10 log (P1/P2) = 10 log (V1^2/V2^2) = 10 log (V1/V2)^2 = 20 log >> (V1/V2), >> > >> > Then does it follow that, >> > >> > dB = 10 log (aV2^2/V2^2) = 10 log (aV2/V2)^2 = 20 log (a) ? Eq. (2) >> > >> > >> > If this is true, then >> > >> > duty cycle "a" = 10 log (a) from Eq. (1) and >> > >> > = 20 log (a) from Eq. (2) >> > >> > What am I missing? >> >> The original intention of the calculations. >> >> The first relation, dB = 10 log (aP2/P2) = 10 log (a) >> is a "power" relation. >> >> The second relation, dB = 10 log (aV2^2/V2^2) = 20 log (a) >> is a "voltage relation. " >> >> Equating the two is invalid since you're trying to equate >> two different concepts. Doesn't mean anything. >> >> - Doug McKean >> >> >> >> ------------------------------------------- >> 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: >> Michael Garretson: [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: >> No longer online until our new server is brought online and the old >> messages are imported into the new server. >> > > ------------------------------------------- > 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: > Michael Garretson: [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: > No longer online until our new server is brought online and the old > messages are imported into the new server. > ------------------------------------------- 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: Michael Garretson: [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: No longer online until our new server is brought online and the old messages are imported into the new server.
