Stuart, Duty cycle in 15.231 is related to a voltage ratio, therefore 20 log(duty cycle) will provide the correct factor.
Demonstrate it to yourself. Start with a given value (say 100V), multiply this by some duty cycle (say 15% or .15). Convert the result to dB. This is your reference result. Now take 20 log of a duty cycle (.15). Convert your given value (100V) to dB. Add the numbers together, duty cycle dBs to the given value dBs, and behold -- the same answer as the reference result. Best regards, Don > ---------- > From: Stuart Lopata[SMTP:[email protected]] > Reply To: Stuart Lopata > Sent: Thursday, October 18, 2001 12:00 PM > To: emc > Subject: duty cycle correction factors > > > Part 15.231 devices use a duty cycle correction factor to adjust peak > readings. The duty cycle represents the fractional on-time over a given > period of time (that must be under some limit). Anyways, given this > fractional time, d, how do you make the conversion to dB? > > 10log(d) or 20log(d)? > > There have been some misinterpretations, since the readings are made at a > span of zero hertz (voltage readings). Normally, a reduction in voltage > would use the 20log scale. However, since the duty cycle does not > represent > a scale down (it represents the off-time versus on-time), the 10log scale > seems more appropriate. > > I have seen conflicting documents, so would like your professional > opinions! > > Thanks, > > Stuart Lopata > > > ------------------------------------------- > 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.
