Waterfall plots can be generated by Rotate from differing combinations of input data. Let's look at a couple plots using differing units of measurement available on each of the axes. Our first waterfalls that we generated were plots of frequency against time. Rotate also allows you to plot frequency against RPM as in this plot below. Also in this plot we have placed a cursor (yellow) on the order number 2.003. Note the signature of that order as it relates to RPM in the 2D plot. Note also its diagonal position across the plot.
In this next plot we have graphed Order (not frequency as above) against RPM and also placed the cursor on order number 2.003, the signatures in the 2D box are identical, but the waterfall plots are dramatically different. Order normalization is preferred by some engineers.
Rotate gives you a choice of measurement units for the Frequency Axis: frequency or order! Choices of time, RPM, or number of spectra are available on the RPM Axis. It is also possible to graph other measurements, such as acceleration, with Rotate. Other types of options are available to Rotate users. As we mentioned earlier, the X axis can be specified as Hertz/CPM or orders and the scale can be either linear or log. The Y axis choices are linear, log or dB scale and the Z axis can be RPM, seconds or number. Windowing types available are Hanning, Hamming, Flat top and Uniform with narrowband (peak) or wideband (rms) correction. Averaging numbers can be from 1 to 500 and of stable (linear), peak hold or exponential types. User selected overlap is from 0 to 50%. Spectral lines are available from 50 to 12800 and frame or block size from 128 to 32768 samples. Options are available for tracking, signal domain and A, B, or C weighting. All these options add up to a program that is flexible enough to meet many, many needs. Notice the top pane in these plots. Rotate has the ability to display the cursor cut as the cursor slices through the data. Rotate's cursoring capability is one of it's most outstanding features. The cursor will follow the surface of the waterfall data, so that you see where you are regardless of perspective. Also, using the arrow keys, you can step from ridge to ridge, automatically, based on local energy calculations. Our next screen demonstrates some of the flexibility of Rotate's cursors. |
