I've created a Sound Level Meter (sound pressure, Lp) for some basic use. I've checked against some test signals as IEC61672 demands it and looks ok (LAF continous tone and LAF&LAS 4kHz bursts).
I'ts a crude work, It will only work with 51,2ksps data. I only need to use 51,2ksps that's why. I need to implement bilinear transformation to calculate the filters for other data rates. It will work with data that is not at 51,2ksps but the time will be incorrect and the filters will give an incorrect result. I've used Christophe Couvreur's Octave Matlab code to generate the A and C filters coefficients.
The RMS is calculated in 25ms intervals (40Hz) as some standards for noise measurements demands for 30ms max.
I'm in the process of implementing 1/3rd octave visualization instead of the frequency spectrum, I have code working but I'm not shure if it's working ok. Do you know of some ready code to do this?
I should buy SVT in the future, but I'm not sure when, it can take a year or more, this is why I did it.
Labview 2015 Full development system
1. Open and run it with simulated signal, or point to a test signal (tdms file).
Does anybody found another example as mine? I've looked but I didn't find any in Labview (not using Matlab script).