Do Missing Tachometer Pulses Mean The End Of The Road For Your Test?

Creating a good quality tachometer signal is one of the hardest parts of analyzing rotating machinery. So what happens if we have missing tachometer pulses? The data looked great until we tried to perform some in-depth torsional vibration analysis. And now we no longer have the component or vehicle to retest it.  Do we have to scrap the whole test? Was all that time wasted? Not necessarily…

(more…)

Continue ReadingDo Missing Tachometer Pulses Mean The End Of The Road For Your Test?

Interpolation Versus Resampling To Increase The Sample Rate

These are two different techniques aimed at different objectives. First consider a simple sinewave that has been sampled close to the Nyquist frequency (sample rate/2).

Figure1

Visually this looks very pointy. We will examine it using a filter based interpolation and a classical curve fitting procedure to obtain a better representation.

(more…)

Continue ReadingInterpolation Versus Resampling To Increase The Sample Rate