I am using the Q-MED volume velocity acoustic source and MIMO FRF Testing to generate acoustic FRF’s. However, the sensitivity provided for the Q-source has units of mV/m^3 and therefore my measurements have units of Pa/m^3. How can I get the more common unit for acoustic FRF’s of (Pa/m^3/s^2) ?
Hello, this is correct. The Q-MED is a volume displacement sensor.
Also, if the sensitivity is negative make sure that you reflect that. Either enter the sensitivity as negative or add the Polarity field to Channel Setup and set that to negative.
I guess your next question will be, what to do with the FRF? The FRF wil be Pa/m^3. I believe if you integrate that you will get Pa/(m^3/s) and if you double integrate you will get Pa/(m^3/s^2). I have not used that exciter myself, but that seems to make sense to me if you want Pressure over volume velocity or volume acceleration.. If not, I am sure someone will correct me.
Some additional information:
AntMoon I agree with Kevin….
The double integration of data with units of (Pa/m^3) will indeed lead to FRF data with units of (Pa/(m^3/s^2)).
Additionally, I wanted mention a couple of easy ways perform the double intergation. One method simply changes the units in the display and another actually creates a new curve with your desired units. I have listed both methods below so can choose whichever one meets your needs.