Hi there, 

I have a problem with a data aquisition process. Via the soundcard and speakers I 
generate a signal and record it with a microphone. The code is as follows:

ao = analogoutput('winsound');
addchannel(ao,1);
set(ao,'SampleRate',fs);
ai=analoginput('winsound');
addchannel(ai,1);
set(ai,'SampleRate',fs)
set(ai,'SamplesPerTrigger',n_spt)
putdata(ao,sout');
start(ao);
start(ai);
data        = getdata(ai);
wait(ao,tmax+0.1);

I calculate the phase shift between output and input signal. It should be constant, but it is not. How can I solve this problem?

Cheers