HD ENV has a lot of similarities with SPM HD and uses very similar algorithms, so you may use it in place of SPM HD in many cases.
Figure 1: HD ENV
We can compare the signals generated using the two technologies by measuring a bearing on an oil-injected compressor.
Figure 2: Oil-injected compressor
In Figure 3, you can see a clear symptom of an inner race fault. SPM HD and HD ENV with Filter 3 both provide clear results.
Figure 3: SPM HD, HD ENV Filter 3, and Filter 4
HD ENV with Filter 4 is even clearer.
