## How Do I Upsample and Downsample My Data?

This post covers how to upsample and downsample data and the possible pitfalls of this process. Before we cover the technical details let us first explain what we mean by upsample and downsample and why we may need to use it.…

## What Are Vibration, Torsional Vibration & Shaft Twist?

When analyzing rotating shafts some terms are often confused. This post will attempt to explain the differences. So, what are vibration, torsional vibration and twist? What is Vibration? We measure at least one sensor on one channel of our measurement device…

## Pick of Twitter #1 – Acoustics – October 2016

We’ve been carefully tracking acoustics related tweets on Twitter and present here a few of the highlights. We do this sort of thing so that you don’t have to. Don’t forget that you can follow us on Twitter as well…

## Real World Noise & Vibration Measurement – An Interview

Richard O’Sullivan is a respected engineer who has worked throughout the world on noise & vibration measurement solutions in automotive, aerospace and beyond. Hear about some of the problems he has faced and how Prosig’s systems have helped him solve…

## The Effect of the Nyquist Theory on Rotational Order Analysis

Nyquist theory is generally understood, but this understanding usually relates to time sampling and the conversion to the frequency domain. Rotational order analysis and the effect of the Nyquist frequency are, however, less well understood. Most engineers will understand the…

## Seismic Qualification Testing (Part 1)

Seismic Qualification Testing for US Nuclear Power Generating Stations Part 1 (Random Vibration Testing) The nuclear power industry in North America (USA, Canada & Mexico) requires seismic qualification testing for any equipment being installed in nuclear power generating stations. If…

## Exhaust Vibration Measurement – A Case Study

Exhaust Vibration Measurement – Customer Requirement One of Prosig’s customers needed to perform exhaust vibration measurement on some of their vehicles. They contracted Prosig to take the measurements and provide reports of the results. Prosig provided a P8020 data acquisition systems and DATS software. The…

## What Is Amplitude Quantization Error?

Amplitude Quantization Error – Summary This article explains what amplitude quantization error is and what can be done to avoid it. Typically quantization error is caused during acquisition of data. It is synonymous to rounding error. In order to explain…

## Speech Articulation Index – What Does It Mean?

There are many ways to calculate speech articulation index and each has its advantages in different applications. Prosig’s DATS includes four methods for evaluating the Articulation Index as seen in the table below. All four methods are essentially the same and they…

## Viewing Operational Deflection Shapes (ODS) from a Gas Turbine Generator

As its name suggests Operational Deflection Shape analysis shows the vibration pattern experienced during normal operational condition. This is different to other structural vibration tests such as impact hammer tests, bump tests or shaker tests which require a more controlled excitation force and are used to determine specific characteristics of the structure under test, such as natural or resonant frequencies.

## Is Orchestral Noise Damaging Hearing?

Having played the trumpet for over 10 years I have left many an orchestral rehearsal with my ears ringing courtesy of the onslaught of noise from the trombone section behind me. In searching for a topic for my final year research project as part of my studies at Southampton University, the risk of hearing loss to orchestral musicians seemed a natural choice.

## Processing pump data – a classic case of amplitude modulation

When dealing with some vibration data from a pump, we observed some strange phenomena in the data. It turned out to be a classic case of amplitude modulation. Here we explain what that means.

## “The History and Future of Fourier Analysis” Workshop at SAE 2015, Grand Rapids

Are you attending the SAE 2015 Noise and Vibration Conference and Exhibition in Grand Rapids, Michigan, USA from 22nd to 25th June 2015? Why not go and see Dr Colin Mercer, one of our principal authors, co-present the technical session –…

## How Do I Measure Whole Body Vibration?

Whole Body Vibration (WBV) analysis for continuous vibration uses assessment criteria defined in the ISO2631 standard and the EEC vibration directive 2002/44/EC. These assessments are based on the processing of vibration weighted acceleration data (the data must be acceleration data…

## Creating An End of Line Vibration Test System

Prosig was contracted by Imperial Electric in Akron, Ohio to integrate a system for end of line vibration test for electric motors they manufacture. The requirement was to qualify motors under final test to verify that vibration levels are within vibration…

## RMS From Time History And FFT Spectrum

The RMS of a time history is a measure of the signal’s overall energy and is often used when extracting features from a signal for prognosis and trending of vibration data. For a time history which has been digitised at…

## How Do I Calibrate An Impact Hammer?

The intention of this article is not to present any new scientific theories or ground breaking techniques, but to introduce new users to hammer impact testing and remind seasoned technicians of a method of how to calibrate an impact hammer and/or verify the…

## A Guide To Resonance

Our articles on how to measure resonance and natural frequency are always amongst our most popular posts. This isn’t surprising considering what an important concept this is to the measurement of noise and vibration. So, in this post we have…

## What is Operating Deflection Shape (ODS) Analysis?

Operating Deflection Shape (ODS) analysis is a method used for visualisation of the vibration patterns of a machine or structure caused by unknown operating forces. This is different from the study of the vibration patterns of a machine under known external forces, which is usually…

## Sampling and Filtering Data for ISO8041 Compliance and Human Body Vibration Data Weighting

Various human body vibration measurements and assessments are defined in the ISO2631, ISO5349, ISO6954 standards and also in the EEC vibration directive 2002/44/EC. These assessments are based on the analysis of acceleration data that has been weighted (filtered) with appropriate…

## Bearing & Gearbox Vibration Analysis using Demodulation Techniques? (Part 2)

In our previous post on this subject we briefly looked at how we can use the detailed design information of bearings and gearboxes to look for specific fault conditions by collecting vibration information and analysing their frequency spectra. Amplitude modulation of…

## Bearing & Gearbox Vibration Analysis Using Demodulation Techniques (Part 1)

Bearings and gearbox vibration are fundamental issues for rotating machines in many industrial applications. These are critical components and, as such, any failure can prove expensive in both repair cost and down-time. Because of this condition monitoring has become increasingly…

## Examples of Structural Animation

The video below shows some examples of structural animation using Prosig’s DATS software.

## How do we design or modify a system to avoid resonance?

After finding the natural frequency of a system, what could be done to stop or reduce the systems resonance being excited? Basically put, how do we avoid resonance This is simple in theory, but not always so simple in practice.…

## Three Methods For Analyzing Vibration In Rotating Components

In this post we will first look at how to process data from rotating machinery. Then we will focus on shaft or gear train twist. Let’s look at 3 different ways to measure and analyse rotating shafts. Each one has…

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