writer
240
edits
Line 7: | Line 7: | ||
===What is Order Tracking?=== | ===What is Order Tracking?=== | ||
When doing measurement on | When doing a measurement on rotating machinery, it is often useful to display a spectrum in the behavior of harmonics or sub harmonics related with the shaft speed. | ||
If the shaft speed varies, each harmonic of the shaft rate needs to appear at a fixed point into the spectrum, so called order. | If the shaft speed varies, each harmonic of the shaft rate needs to appear at a fixed point into the spectrum, so called order. | ||
Line 13: | Line 13: | ||
The basics to make such analysis are to control the sampling rate of the analyzed signals in order to get an equal number of samples independently of the shaft speed. | The basics to make such analysis are to control the sampling rate of the analyzed signals in order to get an equal number of samples independently of the shaft speed. | ||
The classical way uses a tracking ratio synthesizer based on phased locked loop oscillator which generates a constant number of sampling pulses during one shaft revolution. This synthesizer also controls variable cut off frequency of analog anti-aliasing filters. | The classical way uses a tracking ratio synthesizer based on phased locked loop oscillator which generates a constant number of sampling pulses during one shaft revolution. This synthesizer also controls variable cut off frequency of analog anti-aliasing filters. They are adapted to the variable sampling frequency that is itself depending on the frequency bandwidth. | ||
===How the OROS Analyzer Works?=== | ===How the OROS Analyzer Works?=== |