This example shows how to measure the rotational speed of an engine from an automobile's muffler noise using a measurement microphone. Since the component of pulsation relating to the engine rotation is included in the muffler noise, the engine's rotational speed can be obtained by this pulsation frequency component. By setting the number of ignition firings per one crankshaft rotation, the rotational speed can be measured to perform frequency analysis through FFT calculation. Please note, however, that depending on muffler performance, there may be cases when measurement cannot be performed.

Analog signal output and sensor signal monitor output are provided as standard function. Analog signal output can be used for recording the fluctuation of rotational speed by pen-recorder and so on, and sensor signal monitor output can be used in order to check the shape of signal waveform.