Prosig Noise & Vibration Measurement Blog » phaseless

Analyzing Shaft Twist And Repairing Damaged Tachos

Dr Colin Mercer — Wed, 19 Oct 2005 09:22:40 +0000

A shaft has been instrumented with two shaft encoders, one at each end. Each shaft encoder gives out a once/rev pulse and a 720 pulses/rev signal. Each signal was digitised at 500,000 samples/second. The objective is to measure the twist in the shaft and analyze into orders. The test stand was already equipped with a data [...]

High Pass Filtering And Tacho Signals

Dr Colin Mercer — Wed, 06 Jun 2001 17:13:29 +0000

It is sometimes necessary to pass a signal through a high pass filter to eliminate low frequency signals. These may arise for instance from whole body vibrations when perhaps our interest is in higher frequency components from a substructure such as an engine or gearbox mounting. The vibration levels are speed sensitive and the [...]

Removing Phase Delay Using Phaseless Filtering

Dr Colin Mercer — Wed, 06 Jun 2001 09:16:07 +0000

In many instances we need to filter a signal to remove unwanted frequencies. If we use classical filters such as Butterworth, Chebyshev or even Bessel then a phase delay is introduced. This phase delay is itself a function of frequency so that the signal content at one frequency is delayed a different amount to that at [...]