Order Waveform Extraction

Use a spectral map or order power spectrum to identify the most significant orders in a sound or vibration signal. After identifying the most significant orders, you can extract an order waveform to get detailed information for individual orders.

You can extract order waveforms to isolate specific orders from a sound or vibration signal. The following figure shows a waveform signal and an extracted order waveform.

You can see the contribution of the fourth order to the overall waveform signal. You also can calculate the running root-mean-square (RMS) value of a certain order from the order waveform. You then can use the running RMS value to indicate the amplitude of a certain order.

One feature of order waveform extraction is the ability to play back a time signal. Playing back a time signal enables you to listen to the sound of a certain order or a combination of orders. This feature is useful for applications where a microphone acquires the signal. You can use order waveforms to perform noise analysis and to locate a noise source by comparing the noises that different orders or order combinations generate. The most common applications of this feature are in sound quality engineering. You can analyze and synthesize the sound of several orders and evaluate the subjective perception of these sounds. In automotive noise, vibration, and harshness tests, one example of sound quality engineering is the evaluation of power train components, like the engine, to obtain a more comfortable noise level for passengers.