Hello,
I am trying to play a tone (1K for Example) and record the tone using a microphone. I am using a PCI-4461 to generate and record the tone. I managed to make a somewhat functional program but there are some issues I would like to clear up:
1) I had to make a start and check time function to determine if the tone plays and is recorded for the appropriate amount of time. If I remove the while loop the tone does not play. I tried using the DAQmx wait until done function but it does not seem to make a difference. Is there anyway I can play and record the tone without monitoring the time?
2) The recorded waveform always has a delay which seems dependent upon the sample rate. Ex: 10000 Samples/Sec results in 83 sample delay, 20000 Samp/Sec results in 114 sample delay. I read in some other articles that samples are stored in the buffer and that reading 60ish samples before the actual measurement would clear up the problem. I tried reading samples before the tone is generated but the delay is still present. Currently I am using post processing to remove the delay, is there anyway to only record the tone that is played. Am I triggering the read properly?
Let me know if I should post the VI. Also incase anyone is familiar with acoustics how do I convert a waveform of Voltage vs time to dBV/Pa
Thanks,
E
