Spectral Map
- Updated2024-06-07
- 2 minute(s) read
Spectral Map
A spectral map is a three-dimensional display of sound or vibration spectra as a function of time or speed. The spectra can be frequency or order spectra.
A spectral map provides an overview of the frequency or order content of a signal related to time or speed. A spectral map can help you locate strong sound or vibration components, identify the components changing with the rotational speed, and identify the fixed components within a certain frequency range.
The following figure shows the spectral map, in colormap display, of the vibration signal acquired from a gearbox casing in a run-up and run-down test:
The strong order components on this spectral map change with time. The vibrations in the frequency range from 1.8 kHz to 3.0 KHz are stronger than vibrations in other frequency ranges. This range is the resonance range of the gearbox. In general, a spectral map helps you obtain overview information such as how signal components change and the location of significant frequencies or order components.
Because a spectral map provides overall signal information, you perform a spectral map calculation as the first step in order analysis applications. You can locate the signal components of interest from the view of time, speed, frequency, or order. After you locate the components of interest, you can perform further analysis with other functions such as the order power spectrum, order waveform, or order magnitude and phase.
Related Information
- Order Power Spectrum
An order power spectrum provides a quantitative description of the amplitude or power of the orders in a signal.
- Order Waveform Extraction
An order waveform is the time signal associated with a certain order, which is synchronous to the rotational speed. Unlike an order power spectrum, which provides information for all of the orders of a certain time block signal, an order waveform provides information only for one particular order relative to time.
- Order Tracking
You can perform order tracking by computing the order magnitude and phase from an even-angle signal. You also can compute the magnitude and phase of a specific order from the order waveform.