http://www.k-wave.org/forum/topic/the-relationship-between-frequency-and-attenuation Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 09:50:42 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/the-relationship-between-frequency-and-attenuation#post-7406 Fri, 17 Apr 2020 16:11:23 +0000 Bradley Treeby 7406@http://www.k-wave.org/forum/ <p>Hi wang_feng_2020,</p> <p>Unfortunately, it's impossible to say without seeing the rest of your code. One comment, attenuations on the order of -80 dB are very large, and about the same performance as the PML used in k-Wave. It's possible that you've reached the noise floor.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/the-relationship-between-frequency-and-attenuation#post-7369 Sun, 05 Apr 2020 06:25:34 +0000 wang_feng_2020 7369@http://www.k-wave.org/forum/ <p>Hi,Brad.<br /> Here is my code:</p> <p>% muscle<br /> medium.sound_speed = 1588 * ones(Nx,Ny); % [m/s]<br /> medium.density = 1090 * ones(Nx, Ny); % [kg/m^3]<br /> medium.alpha_coeff = 0.6*ones(Nx,Ny); % [dB/(MHz^y cm)]<br /> medium.BonA = 7.8*ones(Nx,Ny);<br /> medium.alpha_power =1.2;</p> <p>Theoretically, the higher the frequency of the source, the greater the attenuation factor.<br /> When the frequency of the source is 1MHz, the attenuation is -82dB. When the frequency of the source is 2MHz, the attenuation is -76dB.</p> <p>This is the opposite of the theoretical calculation,Why does this happen? </p>