I need to code a program to do these things. I want to use the sound
card like an adquisition data system. I must move the microphone with an
steeper motor, at the same time i need generate a tone with the sound card
and play this tone in one loudspeaker and, at the same time i need to record
the input from the microphone. These things are for make an Impedance
Measurement Tube. The Impedance Measurement Tube is used in measuring the
acoustic absorption coefficient, acoustic reflection coefficient and
normalized impedance of small test samples in the frecuency range 90 Hz to
5.5 KHz. PC acts as system controller. The loudspeaker is conected to the
tube and this theory assumes plane-wave propagation. In the other end of the
tube is test sample. The method of measuring involves the decomposition of a
broad-band stationary random signal into its incident and reflected
components. So i need to know the position and value of the stationary wave.
Moving the microphone throug the tube and recording its value i'll be able
to know the position from the test sample and the value of the stationary
wave. Then i'll change the frecuency of the tone and i'll repeat the entire
process.
With these data i need calculate the acoustic absorption coefficient.
I hope this information aid you in what i need.
Thank you.
Antonio.
