underwater acoustic wave Signal to Noise Ratio (SNR)
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I am trying to plot the curve of Signal to Noise Ratio for Acoustic waves in Underwater. I am finding two problems.
1- The SNR must be decreaseing for higher frequency values, however, i am seeing increase of SNR with the increase of Frequencies.
2- While ploting SNR there should be some peak SNR for certain frequencies, however, i am seeing a smooth curve.
The equations i am trying to plot is
10log Ns(f)=40–20 (S-0.5)+26log f–60log (f + 0.03)
10log Nth(f) = -15 + 20logf
10logNw(f )= 50 + 7.5√W + 20 log f– 40 log (f+0.4)
10log Nt(f) = 17 – 30 log f
Can someone please identify the problem.
回答 (2 件)
Paul 2022 年 9 月 17 日
At a minimum:
SSs is still using log, probably should be log10
The equation coded for ns doesn't match the equation in the question. The second term in the former has +20 but the latter has -20.
The computatoin of N doesn't need to be inside the loop, but that doesn't really matter.
Also, all of this code could be implemented without loops at all, for example:
f = 1:100;
nth = -15 + 20*log10(f);
Chris 2022 年 9 月 17 日
編集済み: Chris 2022 年 9 月 17 日
Your individual noise sources add up to a decreasing signal, and I'm not sure af is on the right scale.
Should S in the noise equations be equal to 1, or to the signal?
Is the signal supposed to be 1, -190, or 10*log10(50) (or 20?) ?
And is 1-100 Hz the correct frequency range?
f = 1:100;
TL = SSs + af.*10^(-3);
nt = 17-30.*log10(f);
ns = 40+20.*(1-0.5)+26.*log10(f)-60.*log10(f+0.03);
nw = 50+20.*log10(f)-40.*log10(f+0.4)+7.5.*6^(0.5);
nth = -15+20*log10(f);