## Technical Articles

Supplier:
Prosig USA, Inc. has published these technical articles:

(Engineering and Scientific Software)
This article will attempt to explain the basic theory of the frequency response function. This basic theory will then be used to calculate the frequency response function between two points on a... (View Full Article)
(Engineering and Scientific Software)
Accelerometers are robust, simple to use and readily available transducers. Measuring velocity and displacement directly is not simple. In a laboratory test rig we could use one of the modern... (View Full Article)
(Engineering and Scientific Software)
These days most people collecting engineering and scientific data digitally have heard of and know of the implications of the sample rate and the highest observable frequency in order to avoid... (View Full Article)
(Engineering and Scientific Software)
In this article we will look at why we need to consider energy correction when producing frequency spectra and how we go about it. We will use a perfect, 'special case' signal to keep the explanation... (View Full Article)
(Engineering and Scientific Software)
It is quite straightforward to apply "classical" integration techniques to calculate either a velocity time history from an acceleration time history or the corresponding displacement time history... (View Full Article)
(Acoustic and Audio Equipment)
Sometimes we are asked about the differences between an acoustic camera and a sound intensity probe and which of the two is better for a particular application. There is no straightforward answer as... (View Full Article)
(Engineering and Scientific Software)
From time to time I meet engineers who are interested in the conversions between acceleration, velocity and displacement. Often, they have measured acceleration, but are interested in displacement or... (View Full Article)
(Data Acquisition Products)
Before we discuss the use of data windows, we should first remind ourselves of three basic properties of the FFT (Fast Fourier Transform) process. First, energy information in signal must be preserved... (View Full Article)
(Engineering and Scientific Software)
An investigation was made of a sample of automotive components where some were exhibiting a high frequency "tick" or rattle during each operating cycle. This feature could be heard above the normal... (View Full Article)
(Vibration and Acceleration Sensing)
Creating a stable, good quality tacho signal can be one of the hardest parts of analyzing rotating machinery. So what happens if our carefully designed and implemented tacho misses a few pulses? The... (View Full Article)
(Engineering and Scientific Software)
DATS smoothing PROTOR runup vibration microphone Fourier aliasing P8000 strain gauge de-spike ENBW despike muffler gearbox strain gage engineering acoustic phaseless spikes Butterworth fatigue... (View Full Article)
(Process Controllers)
Prosig were recently involved in the validation of a closed loop control system for an automotive pump supplier. The customer has a large number of test cells, each test cell has 8 pumps continually... (View Full Article)
(Engineering and Scientific Software)
In many cases only significant events, such as bumps or other transients in a signal are of relevance. The objective is to be able to isolate these events in a meaningful manner so that they may be... (View Full Article)
(Engineering and Scientific Software)
This application note describes the test and measurement process for the fatigue testing and development cycle of a component.... (View Full Article)
(Engineering and Scientific Software)
For various reasons data captured in the real world often contains spikes that will give erroneous results when analyzed. DATS for Windows provides various ways of editing and removing these... (View Full Article)
(Data Acquisition Products)
At least one manufacturer of data acquisition systems claims to achieve an incredibly high dynamic range (160dB) when capturing data. This is supposedly achieved by the use of dual-range data... (View Full Article)
(Engineering and Scientific Software)
Each of the different social networks has its own strengths and weaknesses in terms of how useful it will be in a work or educational environment. We will look at just a few of the different sites.... (View Full Article)
(Vibration and Acceleration Sensing)
We can distinguish between quantities which have magnitude only and those which have magnitude and are also associated with a direction in space. The former are called scalars, for example, mass and... (View Full Article)
(Engineering and Scientific Software)
In this article we will look at the basic steps behind a simple rotating machinery study. We won't look in great detail at some of the techniques involved - these are dealt with elsewhere on the Noise... (View Full Article)
(Engineering and Scientific Software)
Standards DIN 4150-2:1999-06 and DIN 45669-1:1995-06 provide a means of assessing the effect on human beings of vibration caused by vehicle traffic, trains both above and below ground, construction... (View Full Article)
(Vibration and Acceleration Sensing)
A vibration problem arose at an Open Cycle Gas Turbine. Following an outage on the four gas turbines and two SSS clutches, the machine returned to service with unacceptable vibration levels on some... (View Full Article)
(Data Acquisition Products)
This article documents an investigation into voltage levels provided by an automotive cigar lighter socket. These sockets are nowadays used to power a wide variety of devices. It is, in fact, rare for... (View Full Article)
(Engineering and Scientific Software)
These are two different techniques aimed at different objectives.... (View Full Article)
(Engineering and Scientific Software)
The Articulation Index or AI gives a measure of the intelligibility of hearing speech in a given noise environment. The metric was originally developed in 1949 in order to give a single value that... (View Full Article)
(Data Acquisition Products)
In this note the different types of transducers that can be used with the Prosig P8000 series data acquisition system are discussed. The article deals with the design and function of the different... (View Full Article)
(Engineering and Scientific Software)
Torsional vibration is of key importance in the area of vehicle development and refinement. The main contributory source is the engine where periodically occurring combustion cycles cause variation in... (View Full Article)
(Engineering and Scientific Software)
The following application note shows the steps taken to perform a structural analysis on an automotive exhaust pipe (muffler) structure with the aim of improving the structural damping properties of... (View Full Article)
(Engineering and Scientific Software)
Using Prosig's P8000 series data acquisition system with DATS signal analysis software, torsional analysis (crank jitter) was performed on an automotive engine attached to an engine dynamometer. The... (View Full Article)
(Engineering and Scientific Software)
From time to time I meet engineers who are interested in the conversions between acceleration, velocity and displacement. Often, they have measured acceleration, but are interested in displacement or... (View Full Article)
(Engineering and Scientific Software)
Normally when we are analysing a signal it is a purely real signal, that is it has no imaginary part. A classic example is of course a sine wave. When we analyse a signal with a Fourier transform,... (View Full Article)
(Engineering and Scientific Software)
Order cuts are taken from a set of FFTs, each one at a different rpm. The rms level is then found as the Square root of the Sum of the squares of each of the FFT values.... (View Full Article)
(Engineering and Scientific Software)
By combining a speed signal with a data signal and using the Short Time FFT algorithm (Hopping FFT), it is possible to extract order data directly as a function of time (Orders from Hopping FFT)... (View Full Article)
(Engineering and Scientific Software)
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... (View Full Article)
(Engineering and Scientific Software)
Shaft displacement is an important vibration measurement for rotating machines. Shaft displacement is usually monitored by non-contact shaft displacement probes such as eddy-current probes. These... (View Full Article)
(Engineering and Scientific Software)
The requirement was to develop a 'standard' test for assessing the sound quality of power steering pumps in vehicles. Measurements needed to be objective so that the method would be suitable for... (View Full Article)
(Data Acquisition Products)
A strain gauge is an electrical sensor which is used to accurately measure strain in a test piece. Strain gauges are usually based on a metallic foil pattern. The gauge is attached to the test piece... (View Full Article)
(Data Acquisition Products)
This note is based on a real requirement presented to Prosig by a prospective user. It's the sort of challenge that we relish. This case is a great example of a real-world signal processing... (View Full Article)
(Engineering and Scientific Software)
A common requirement in noise and vibration analysis is to find the overall level of a signal as a function of time. Now the overall level is a measure of the total dynamic energy in the signal. That... (View Full Article)
(Vibration and Acceleration Sensing)
When monitoring vibration on large gas or steam turbines and generators with fluid-film bearings, the relative movement of the shaft within the bearing is typically measured by a pair of shaft... (View Full Article)
(Engineering and Scientific Software)
(Engineering and Scientific Software)
The use of a vibration condition monitoring system for monitoring vibration from large rotating machines fitted with fluid-filled journal bearings such as steam or gas turbines is well understood.... (View Full Article)
(Engineering and Scientific Software)
When using vibration data, especially in conjunction with modelling systems, the measured data is often needed as an acceleration, as a velocity and as a displacement. Sometimes different analysis... (View Full Article)
(Vibration and Acceleration Sensing)
Have you ever wondered if there is a vibration condition monitoring system that can be installed anywhere and then monitored from anywhere else? Even on your smartphone? Well, there is. The following... (View Full Article)
(Engineering and Scientific Software)
Ever been lying on the beach and begun to wonder about the state of your LP turbines. Or out on business and anxious to know if that troublesome exciter bearing has settled down? Well with a Prosig... (View Full Article)
(Engineering and Scientific Software)
Any vibration signal may be analyzed into amplitude and phase as a function of frequency. The phase represents fifty percent of the information so it is most important to measure phase for vibration... (View Full Article)
(Engineering and Scientific Software)
When measuring noise and vibration in rotating machines, especially complex devices like automobile engines, it is very important to fully understand what is being measured and what analyses need to... (View Full Article)
(Engineering and Scientific Software)
(Data Acquisition Products)
Most engineers are probably familiar with or have come across the decibel or dB as a unit of measurement. Its most common use is in the field of acoustics where it is used to quantify sound levels.... (View Full Article)
(Engineering and Scientific Software)
In technical terms, resonance is the tendency of a structure or material to oscillate at maximum amplitude at a certain frequency. This frequency is known as the structure's resonant frequency.... (View Full Article)
(Engineering and Scientific Software)
The term synchronous data is usually applied to vibration or acoustic data that is captured from an item of rotating equipment at regularly spaced angle intervals as distinct from regularly spaced... (View Full Article)
(Acoustic and Audio Equipment)
We're often asked what is the difference between free field microphones, diffuse field microphones and pressure microphones. For a run-of-the-mill 1/2" inch microphone the short answer is nothing.... (View Full Article)
(Data Acquisition Products)
Prosig P8000 systems use differential inputs, but what are they and why are they so special? This subject is not always fully understood and, therefore, the focus of this article is to try to make the... (View Full Article)
(Engineering and Scientific Software)