http://www.k-wave.org/forum/topic/how-to-increase-the-bandwidth-of-photoacoustic-signal Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:40:21 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/how-to-increase-the-bandwidth-of-photoacoustic-signal#post-8518 Mon, 25 Apr 2022 19:47:04 +0000 bencox 8518@http://www.k-wave.org/forum/ <p>Hi johnson870405, </p> <p>The maximum frequency that k-Wave can support will depend on the grid spacing, so first you need to ensure your grid spacing is fine enough. Second, the frequency content of a photoacoustic wave will depend on its shape. Try a source one grid point thick to get the broadest bandwidth.</p> <p>Best wishes<br /> Ben </p> http://www.k-wave.org/forum/topic/how-to-increase-the-bandwidth-of-photoacoustic-signal#post-8499 Fri, 15 Apr 2022 07:35:49 +0000 johnson870405 8499@http://www.k-wave.org/forum/ <p>Hello forum:</p> <p>I'm trying to simulate PA signal with high frequency probe setting(central frequency=20MHz). However, I found the spectrum of PA signal I received was located at low frequency(approximate 5MHz), which did not match to the frequency response of my probe setting.<br /> I've found that the bandwidth will increase when the grid is split into smaller size, but the improvement was limited.<br /> Is there any wrong setting in my code, or any parameter I should modify, or maybe I just need to set smaller grid to get wider bandwidth?</p> <p>%% My code %%%%%%%%%%%%%%%%%%<br /> % Grid setting<br /> Nx = 1024; % number of grid points in the x direction<br /> Ny = 1024; % number of grid points in the y direction<br /> dx = 0.05e-3; % grid point spacing in the x direction [m]<br /> dy = 0.05e-3; % grid point spacing in the y direction [m]<br /> kgrid = kWaveGrid(Nx, dx, Ny, dy);<br /> kgrid.makeTime(1480);</p> <p>% medium setting<br /> medium.sound_speed = 1480 * ones(Nx, Ny);<br /> medium.density = 1000 * ones(Nx, Ny);</p> <p>% source setting<br /> disc_magnitude = 5; % [Pa]<br /> cx = 810; % [grid points]<br /> cy = 512; % [grid points]<br /> Disc_radius = 0; % [grid points]<br /> Disc_1 = disc_magnitude * makeDisc(Nx, Ny, cx, cy, Disc_radius);<br /> source.p0 = Disc_1;</p> <p>% sensor setting<br /> sensor.mask = [];<br /> x_start = 10; x_end = 10;<br /> for Nelement = 1:128<br /> sensor.mask = [sensor.mask;<br /> x_start, (Ny/2) + (Nelement-64)*6-6, x_end, (Ny/2) + (Nelement-64)*6-1];<br /> end<br /> sensor.mask = sensor.mask.';</p> <p>% simulation<br /> sensor_Data = kspaceFirstOrder2DG(kgrid, medium, source, sensor);<br /> for Nelement = 1:128<br /> temp = squeeze(sensor_Data(Nelement).p);<br /> data(Nelement,:) = sum(temp, 1);<br /> end</p> <p>for i = 1:128<br /> RFData(i,:) = gaussianFilter(data(i,:), 1/kgrid.dt, 20e6, 80);<br /> end<br /> %%%%%%%%%%%%%%%%%%%%%%%%%%%<br /> Thanks. </p>