http://www.k-wave.org/forum/topic/data-unit-conversion-from-sensor Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 00:20:44 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/data-unit-conversion-from-sensor#post-1059 Fri, 23 Nov 2012 01:33:36 +0000 Bradley Treeby 1059@http://www.k-wave.org/forum/ <p>Hi toxie87,</p> <p>Sorry, I should have mentioned, the value for <code>p_output</code> should be the RMS (root mean squared) value of your output signal (in steady state if you are using a continuous wave input). This will be a single positive number.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/data-unit-conversion-from-sensor#post-1056 Fri, 23 Nov 2012 00:09:41 +0000 toxie87 1056@http://www.k-wave.org/forum/ <p>Thanks for the reply Brad. I`m already using the formula u gave me, but due to the negative values, as a result i have complex numbers. Also the readings are pretty strange to me. 0.2246 is the maximum at the sensor and after the formula, the max is -Inf, the second largest is 186.72dB ?!?? It should be 81dB by my calculations. Am i wrong ? </p> http://www.k-wave.org/forum/topic/data-unit-conversion-from-sensor#post-1055 Thu, 22 Nov 2012 23:48:07 +0000 Bradley Treeby 1055@http://www.k-wave.org/forum/ <p>Hi toxie87,</p> <p>Assuming you are doing linear simulations, the magnitude of your output scales linearly with the magnitude of your input (so in your case, if your input amplitude was 2 instead of 1, your output values would range from -0.4 to 0.4). </p> <p>If you know the actual pressure of your source in Pascals, you can use this to calculate the magnitude of your output in Pascals. You can then convert Pascals to a sound pressure level in dB using the formula <code>20*log10(p_output/p_ref)</code>, where <code>p_ref = 20e-6;</code></p> <p>If you want a relative drop in dB, you can calculate this directly using by setting p_ref equal to your input magnitude (the scaling of the input and output doesn't matter, as long as they are the same).</p> <p>Hope that helps!</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/data-unit-conversion-from-sensor#post-1053 Thu, 22 Nov 2012 23:28:50 +0000 toxie87 1053@http://www.k-wave.org/forum/ <p>I`m doing some simulations using this toolbox and i must say i love it.<br /> Also i have a question. I`m generating some signals in simulink (Amplitude=1). Have 2 sources and 1 sensor. Currently only 'p' is recorded. The resulting value at the sensor_data.p is from -0.2 to 0.2 . How do i convert those into dB ? I need to get simulation results, and then compare it with microphone recordings, to see if they "match" . </p>