LabVIEW
Audible clicks using NI 9260
Ok, Not sure where to post this as I'm unsure if it's hardware or software, but I'm going with software for now.
I am using an NI 9260 to generate various acoustic test signals. However at the beginning and end of each signal there is an audible pop. After a little hunting round I came across this post which describes and on the face of it solves my problem.
I have been using LabView off and on for almost a decade now and still rely on the DAQmx Express VI's (sorry Coq_Rouge).
The problem I am running into now, trying to move away from the express vi is when the sequence gets to the "DAQmx Wait Until Done.vi".
If I match the duration of the test signal to the number of samples in the 'Create Task' section I get the following error.
If I make the duration of the test signal shorter I get.
The VI's I have attached are intended to work in the following way.
Speaker driver.vi - This is what I started with and was producing the pops. After reading the above thread I decided to try and split the Express VI into three sections, the initialisation and shutdown of the NI 9260 module was moved into Test sequence.vi.
Test sequence.vi just passes a list of filter midband frequencies into the speaker driver(2).vi, but now I am also trying to get it to initialise the NI 9260 so that in theory I only get the pop at the beginning and end of the sequence rather than between each signal, if the pop is due to the NI 9260 switching on and off.
OK, some developments. I've been held up by an our of memory error which I have now resolved.
I now manage to get my test sequence to run through without any errors or crashing, however I still have the clicking.
I have looped the output of my 9260 straight back into my 9232 and can see the switching occurring between test tones.
I have attached my vi's saved in version 12.
My method to try and eliminate the action is to remove any DC component of the signal by subtracting the average from the signal. I have also tried ramping up from 0 and back down to zero at the beginning and end of each tone without success.
I could in theory generate all of my individual waveforms then put them together so that the 9260 isn't switching in between, however I need to be able to control the final program in between each tone, and the total test sequence is several minutes long.
