How can I get 2 signal differences in log scale?
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Can anybody help me, please!! I have a problem, hope you can help me! I have 2 signals in logarithmic scale, their power levels are different. The plot is here: https://www.dropbox.com/s/17dkngq0a4dqzgc/plot.bmp
I need to subtract this 2 signals and get their power level differences in dB, for example, for 1K level difference is appx. 30 dB. All results I need to plot in log scale as well. I used 10^(db/20) to get them into power scale, but do not know how to get them back to dB scale. So, which command to choose to subtract them in log-scale??
Thank you in advance!!
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Answers (2)
Iain
on 4 Jul 2013
You can get the ratio between the power levels simply by taking dB1 - dB2. This is probably more sensible unless the numbers are very similar.
p1 = 10^(10*dB); % etc
dp = p1 - p2
ddB = 10*log10(dp); %
Thats to do it through power. For voltage or current:
i1 = 10^(20*dB1);
di = i1 - i2
ddB = 10*log10(di);
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