20log(d)
time is linear, like voltage
not the square, like power, thus the 20log
- Robert -
Robert A. Macy, PE [email protected]
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San Jose, CA 95112
-----Original Message-----
From: Stuart Lopata <[email protected]>
To: emc <[email protected]>
List-Post: [email protected]
Date: Thursday, October 18, 2001 9:45 AM
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
>
>
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