LAFMax Sound Level

[arathbun]

We are trying to get LAFMax (the maximum A-weighted noise level measured with a fast time weighting) from recorded sound pressure measurements.  We sampled two different ways. One set was taken in one second blocks at 25.6KS/s and the other method was to get a single 20 second block at the same sample rate. 

My thought was to run through a loop that picks off 3200 samples each time, gets Leq, and keeps track of the maximum value found until the entire block has been parsed.  For the one second sample blocks I would have to use the maximum from all of the 20 blocks.

My problem is that I am very new to LabVIEW programming and have very little time to devote to learning before I need these results.  So any pointers would be greatly appreciated.

Thanks

[SerJames · Accepted solution]

Hi arathbun,

Just to make sure I understand, you are or have already acquired all of your data. You now want to set up a simple program that will go through all of it and track the max value found from it all. This will ultimately yield the max value of all the data, including all twenty blocks correct?

Also, I believe this is actually going to all be developed in LabVIEW? SignalExpress does not provide a whole lot of data control, it is great for simple signal acquisition but more complex applications it is a bit beyond its capabilities.

Though you are new to LabVIEW it would be worth some time reading through some of the simple tutorials to get you familiar with the environment and tools.

https://learn.ni.com/learn/article/labview-tutorial

From a high level perspective, it sounds like you need a for loop to run through your sets of data, and use a shift register to store an integer value for the max. Your internal loop would take a new number value and compare it to the current max, and select whichever is bigger as the new max. You could also store your information in an array and use the min/max properties to get similar information and faster results.

Hopefully that will get you pointed in the right direction. If you are indeed using LabVIEW I would recommend that you post in the LabVIEW forums as you will get better support more applicable to your questions.

Regards,