oct?

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honhungoc

Joined: 29 Dec 2006
Posts: 226
Helped: 47

01 Mar 2008 8:11 db/dec

Hi all

Anyone please tell me what is the relationship between dB/dec and dB/oct?

Thank you very much

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zolam

Joined: 03 Oct 2005
Posts: 102
Helped: 9

01 Mar 2008 10:00 db/oct db/dec

take this one for beginning:
http://links.jstor.org/sici?sici=0025-570X(199904)72%3A2%3C104%3APACF%3E2.0.CO%3B2-Z

we deal here with non linear scales: octave (doubling), decade (X10), db - a log function

if we suppose we are talking about linear increases only ( obviously not exactly, but lets assume it)

draw the two lines on the same graph:

for the X axis draw a logarithmic 1-10 scale, and a diagonal increase of 1 db
2nd, draw the same increase of 1 db just to the second sign on the X axis, representing the octave.
now we can aplicate simple trigonometrical formulae and find the difference