Equivalent acoustic source characterization of duct-borne fluid machinery noise is often undertaken by interpolating the results of two-microphone pressure measurements with different external acoustic loads over a linear one-port source model.
Recording of a PCG signal requires a transducer to convert the vibration or sound signal into an electronic signal: microphones, pressure transducers, or accelerometers may be placed on the body surface for this purpose.
The technical elements of the microphone are two pressure gradient condensers, a design that captures extra detail.
Moreover, just as the pressure microphone is the most practical type designed by man, among ears the pressure type is the most widespread and the most highly developed.
A 64 microphone grid allowed pressure contours to be calculated, on a plane parallel to the structure.
A laser vibrometer, a pressure microphone and a high-speed camera are employed to measure the plate vibration, pressure signal, and instantaneous images of the plate motion respectively.
Coughs were detected in three ways: via the microphone, via the pressure transducer and by observing the guinea-pig behaviour which was also captured with an external camera.
Conscious animals were placed in a 4 L plethysmograph which was equipped with an internal microphone and a pressure transducer, and were connected to a Amplifier Interface Unit series pre-amplifier (EMMS, Hants, UK).
The additional random error depends in a simple manner on four quantities; the signal-to-noise ratio of the microphone signals, the pressure-intensity index of the sound field, the frequency, and the microphone separation distance.
Using the above approach, the microphone signal provides a pressure signal for the synthesis of the binaural signal.
A laser-Doppler anemometer is used to sense fluctuating acoustic velocity and a microphone to sense the pressure.
